Move files into src/ and build into build/

1 files changed, 2622 insertions, 0 deletions

diff --git a/src/parse.c b/src/parse.c
new file mode 100644
index 00000000..325131e5
--- /dev/null
+++ b/src/parse.c
@@ -0,0 +1,2622 @@
+// Recursive descent parser for parsing code
+#include <ctype.h>
+#include <gc.h>
+#include <math.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistr.h>
+#include <unictype.h>
+#include <uniname.h>
+#include <signal.h>
+
+#include "ast.h"
+#include "cordhelpers.h"
+#include "stdlib/integers.h"
+#include "stdlib/patterns.h"
+#include "stdlib/tables.h"
+#include "stdlib/text.h"
+#include "stdlib/util.h"
+
+// The cache of {filename -> parsed AST} will hold at most this many entries:
+#ifndef PARSE_CACHE_SIZE
+#define PARSE_CACHE_SIZE 100
+#endif
+
+static const double RADIANS_PER_DEGREE = 0.0174532925199432957692369076848861271344287188854172545609719144;
+static const char closing[128] = {['(']=')', ['[']=']', ['<']='>', ['{']='}'};
+
+typedef struct {
+    file_t *file;
+    jmp_buf *on_err;
+    int64_t next_lambda_id;
+} parse_ctx_t;
+
+#define SPACES_PER_INDENT 4
+
+#define PARSER(name) ast_t *name(parse_ctx_t *ctx, const char *pos)
+
+int op_tightness[] = {
+    [BINOP_POWER]=9,
+    [BINOP_MULT]=8, [BINOP_DIVIDE]=8, [BINOP_MOD]=8, [BINOP_MOD1]=8,
+    [BINOP_PLUS]=7, [BINOP_MINUS]=7,
+    [BINOP_CONCAT]=6,
+    [BINOP_LSHIFT]=5, [BINOP_RSHIFT]=5,
+    [BINOP_MIN]=4, [BINOP_MAX]=4,
+    [BINOP_EQ]=3, [BINOP_NE]=3,
+    [BINOP_LT]=2, [BINOP_LE]=2, [BINOP_GT]=2, [BINOP_GE]=2,
+    [BINOP_CMP]=2,
+    [BINOP_AND]=1, [BINOP_OR]=1, [BINOP_XOR]=1,
+};
+
+static const char *keywords[] = {
+    "yes", "xor", "while", "when", "use", "unless", "struct", "stop", "skip", "return",
+    "or", "not", "none", "no", "mutexed", "mod1", "mod", "pass", "lang", "inline", "in", "if", "holding",
+    "func", "for", "extern", "enum", "do_end", "else", "do", "deserialize", "defer", "do_begin", "and",
+    "_min_", "_max_", NULL,
+};
+
+enum {NORMAL_FUNCTION=0, EXTERN_FUNCTION=1};
+
+static INLINE size_t some_of(const char **pos, const char *allow);
+static INLINE size_t some_not(const char **pos, const char *forbid);
+static INLINE size_t spaces(const char **pos);
+static INLINE void whitespace(const char **pos);
+static INLINE size_t match(const char **pos, const char *target);
+static void expect_str(parse_ctx_t *ctx, const char *start, const char **pos, const char *target, const char *fmt, ...);
+static void expect_closing(parse_ctx_t *ctx, const char **pos, const char *target, const char *fmt, ...);
+static INLINE size_t match_word(const char **pos, const char *word);
+static INLINE const char* get_word(const char **pos);
+static INLINE const char* get_id(const char **pos);
+static INLINE bool comment(const char **pos);
+static INLINE bool indent(parse_ctx_t *ctx, const char **pos);
+static INLINE binop_e match_binary_operator(const char **pos);
+static ast_t *parse_comprehension_suffix(parse_ctx_t *ctx, ast_t *expr);
+static ast_t *parse_field_suffix(parse_ctx_t *ctx, ast_t *lhs);
+static ast_t *parse_fncall_suffix(parse_ctx_t *ctx, ast_t *fn);
+static ast_t *parse_index_suffix(parse_ctx_t *ctx, ast_t *lhs);
+static ast_t *parse_method_call_suffix(parse_ctx_t *ctx, ast_t *self);
+static ast_t *parse_non_optional_suffix(parse_ctx_t *ctx, ast_t *lhs);
+static ast_t *parse_optional_conditional_suffix(parse_ctx_t *ctx, ast_t *stmt);
+static ast_t *parse_optional_suffix(parse_ctx_t *ctx, ast_t *lhs);
+static arg_ast_t *parse_args(parse_ctx_t *ctx, const char **pos);
+static type_ast_t *parse_array_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_func_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_non_optional_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_pointer_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_mutexed_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_set_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_table_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_type(parse_ctx_t *ctx, const char *pos);
+static type_ast_t *parse_type_name(parse_ctx_t *ctx, const char *pos);
+static PARSER(parse_array);
+static PARSER(parse_assignment);
+static PARSER(parse_block);
+static PARSER(parse_bool);
+static PARSER(parse_convert_def);
+static PARSER(parse_declaration);
+static PARSER(parse_defer);
+static PARSER(parse_do);
+static PARSER(parse_doctest);
+static PARSER(parse_enum_def);
+static PARSER(parse_expr);
+static PARSER(parse_extended_expr);
+static PARSER(parse_extern);
+static PARSER(parse_file_body);
+static PARSER(parse_for);
+static PARSER(parse_func_def);
+static PARSER(parse_heap_alloc);
+static PARSER(parse_holding);
+static PARSER(parse_if);
+static PARSER(parse_inline_c);
+static PARSER(parse_int);
+static PARSER(parse_moment);
+static PARSER(parse_lambda);
+static PARSER(parse_lang_def);
+static PARSER(parse_mutexed);
+static PARSER(parse_namespace);
+static PARSER(parse_negative);
+static PARSER(parse_not);
+static PARSER(parse_none);
+static PARSER(parse_num);
+static PARSER(parse_parens);
+static PARSER(parse_pass);
+static PARSER(parse_path);
+static PARSER(parse_reduction);
+static PARSER(parse_repeat);
+static PARSER(parse_return);
+static PARSER(parse_say);
+static PARSER(parse_set);
+static PARSER(parse_skip);
+static PARSER(parse_stack_reference);
+static PARSER(parse_statement);
+static PARSER(parse_stop);
+static PARSER(parse_struct_def);
+static PARSER(parse_table);
+static PARSER(parse_term);
+static PARSER(parse_term_no_suffix);
+static PARSER(parse_text);
+static PARSER(parse_update);
+static PARSER(parse_use);
+static PARSER(parse_var);
+static PARSER(parse_when);
+static PARSER(parse_while);
+static PARSER(parse_deserialize);
+
+//
+// Print a parse error and exit (or use the on_err longjmp)
+//
+__attribute__((noreturn, format(printf, 4, 0)))
+static _Noreturn void vparser_err(parse_ctx_t *ctx, const char *start, const char *end, const char *fmt, va_list args) {
+    if (isatty(STDERR_FILENO) && !getenv("NO_COLOR"))
+        fputs("\x1b[31;1;7m", stderr);
+    fprintf(stderr, "%s:%ld.%ld: ", ctx->file->relative_filename, get_line_number(ctx->file, start),
+            get_line_column(ctx->file, start));
+    vfprintf(stderr, fmt, args);
+    if (isatty(STDERR_FILENO) && !getenv("NO_COLOR"))
+        fputs(" \x1b[m", stderr);
+    fputs("\n\n", stderr);
+
+    highlight_error(ctx->file, start, end, "\x1b[31;1;7m", 2, isatty(STDERR_FILENO) && !getenv("NO_COLOR"));
+    fputs("\n", stderr);
+
+    if (getenv("TOMO_STACKTRACE"))
+        print_stack_trace(stderr, 1, 3);
+
+    if (ctx->on_err)
+        longjmp(*ctx->on_err, 1);
+
+    raise(SIGABRT);
+    exit(1);
+}
+
+//
+// Wrapper for vparser_err
+//
+__attribute__((noreturn, format(printf, 4, 5)))
+static _Noreturn void parser_err(parse_ctx_t *ctx, const char *start, const char *end, const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    vparser_err(ctx, start, end, fmt, args);
+    va_end(args);
+}
+
+//
+// Convert an escape sequence like \n to a string
+//
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstack-protector"
+static const char *unescape(parse_ctx_t *ctx, const char **out) {
+    const char **endpos = out;
+    const char *escape = *out;
+    static const char *unescapes[256] = {['a']="\a",['b']="\b",['e']="\x1b",['f']="\f",['n']="\n",['r']="\r",['t']="\t",['v']="\v",['_']=" "};
+    assert(*escape == '\\');
+    if (unescapes[(int)escape[1]]) {
+        *endpos = escape + 2;
+        return GC_strdup(unescapes[(int)escape[1]]);
+    } else if (escape[1] == '[') {
+        // ANSI Control Sequence Indicator: \033 [ ... m
+        size_t len = strcspn(&escape[2], "\r\n]");
+        if (escape[2+len] != ']')
+            parser_err(ctx, escape, escape + 2 + len, "Missing closing ']'");
+        *endpos = escape + 3 + len;
+        return heap_strf("\033[%.*sm", len, &escape[2]);
+    } else if (escape[1] == '{') {
+        // Unicode codepoints by name
+        size_t len = strcspn(&escape[2], "\r\n}");
+        if (escape[2+len] != '}')
+            parser_err(ctx, escape, escape + 2 + len, "Missing closing '}'");
+        char name[len+1];
+        memcpy(name, &escape[2], len);
+        name[len] = '\0';
+        uint32_t codepoint = unicode_name_character(name);
+        if (codepoint == UNINAME_INVALID)
+            parser_err(ctx, escape, escape + 3 + len,
+                       "Invalid unicode codepoint name: \"%s\"", name);
+        *endpos = escape + 3 + len;
+        char *str = GC_MALLOC_ATOMIC(16);
+        size_t u8_len = 16;
+        (void)u32_to_u8(&codepoint, 1, (uint8_t*)str, &u8_len);
+        str[u8_len] = '\0';
+        return str;
+    } else if (escape[1] == 'U' && escape[2]) {
+        // Unicode codepoints by hex
+        char *endptr = NULL;
+        long codepoint = strtol(escape+2, &endptr, 16);
+        uint32_t ustr[2] = {codepoint, 0};
+        size_t bufsize = 8;
+        uint8_t buf[bufsize];
+        (void)u32_to_u8(ustr, bufsize, buf, &bufsize);
+        *endpos = endptr;
+        return GC_strndup((char*)buf, bufsize);
+    } else if (escape[1] == 'x' && escape[2] && escape[3]) {
+        // ASCII 2-digit hex 
+        char *endptr = NULL;
+        char c = (char)strtol(escape+2, &endptr, 16);
+        *endpos = escape + 4;
+        return GC_strndup(&c, 1);
+    } else if ('0' <= escape[1] && escape[1] <= '7' && '0' <= escape[2] && escape[2] <= '7' && '0' <= escape[3] && escape[3] <= '7') {
+        char *endptr = NULL;
+        char c = (char)strtol(escape+1, &endptr, 8);
+        *endpos = escape + 4;
+        return GC_strndup(&c, 1);
+    } else {
+        *endpos = escape + 2;
+        return GC_strndup(escape+1, 1);
+    }
+}
+#pragma GCC diagnostic pop
+
+// Indent is in number of spaces (assuming that \t is 4 spaces)
+PUREFUNC static INLINE int64_t get_indent(parse_ctx_t *ctx, const char *pos)
+{
+    int64_t line_num = get_line_number(ctx->file, pos);
+    const char *line = get_line(ctx->file, line_num);
+    if (*line == ' ') {
+        int64_t spaces = (int64_t)strspn(line, " ");
+        if (line[spaces] == '\t')
+            parser_err(ctx, line + spaces, line + spaces + 1, "This is a tab following spaces, and you can't mix tabs and spaces");
+        return spaces;
+    } else if (*line == '\t') {
+        int64_t indent = (int64_t)strspn(line, "\t");
+        if (line[indent] == ' ')
+            parser_err(ctx, line + indent, line + indent + 1, "This is a space following tabs, and you can't mix tabs and spaces");
+        return indent * SPACES_PER_INDENT;
+    } else {
+        return 0;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////////////     Text-based parsing primitives     ///////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////////////////////////
+size_t some_of(const char **pos, const char *allow) {
+    size_t len = strspn(*pos, allow);
+    *pos += len;
+    return len;
+}
+
+size_t some_not(const char **pos, const char *forbid) {
+    size_t len = strcspn(*pos, forbid);
+    *pos += len;
+    return len;
+}
+
+size_t spaces(const char **pos) {
+    return some_of(pos, " \t");
+}
+
+void whitespace(const char **pos) {
+    while (some_of(pos, " \t\r\n") || comment(pos))
+        continue;
+}
+
+size_t match(const char **pos, const char *target) {
+    size_t len = strlen(target);
+    if (strncmp(*pos, target, len) != 0)
+        return 0;
+    *pos += len;
+    return len;
+}
+
+static INLINE bool is_xid_continue_next(const char *pos) {
+    ucs4_t point = 0;
+    u8_next(&point, (const uint8_t*)pos);
+    return uc_is_property_xid_continue(point);
+}
+
+//
+// Expect a string (potentially after whitespace) and emit a parser error if it's not there
+//
+__attribute__((format(printf, 5, 6)))
+static void expect_str(
+    parse_ctx_t *ctx, const char *start, const char **pos, const char *target, const char *fmt, ...) {
+    spaces(pos);
+    if (match(pos, target)) {
+        char lastchar = target[strlen(target)-1];
+        if (!(isalpha(lastchar) || isdigit(lastchar) || lastchar == '_'))
+            return;
+        if (!is_xid_continue_next(*pos))
+            return;
+    }
+
+    if (isatty(STDERR_FILENO) && !getenv("NO_COLOR"))
+        fputs("\x1b[31;1;7m", stderr);
+    va_list args;
+    va_start(args, fmt);
+    vparser_err(ctx, start, *pos, fmt, args);
+    va_end(args);
+}
+
+//
+// Helper for matching closing parens with good error messages
+//
+__attribute__((format(printf, 4, 5)))
+static void expect_closing(
+    parse_ctx_t *ctx, const char **pos, const char *close_str, const char *fmt, ...) {
+    const char *start = *pos;
+    spaces(pos);
+    if (match(pos, close_str))
+        return;
+
+    const char *eol = strchr(*pos, '\n');
+    const char *next = strstr(*pos, close_str);
+
+    const char *end = eol < next ? eol : next;
+
+    if (isatty(STDERR_FILENO) && !getenv("NO_COLOR"))
+        fputs("\x1b[31;1;7m", stderr);
+    va_list args;
+    va_start(args, fmt);
+    vparser_err(ctx, start, end, fmt, args);
+    va_end(args);
+}
+
+#define expect(ctx, start, pos, parser, ...) ({ \
+    const char **_pos = pos; \
+    spaces(_pos); \
+    auto _result = parser(ctx, *_pos); \
+    if (!_result) { \
+        if (isatty(STDERR_FILENO) && !getenv("NO_COLOR")) \
+            fputs("\x1b[31;1;7m", stderr); \
+        parser_err(ctx, start, *_pos, __VA_ARGS__); \
+    } \
+    *_pos = _result->end; \
+    _result; })
+
+#define optional(ctx, pos, parser) ({ \
+    const char **_pos = pos; \
+    spaces(_pos); \
+    auto _result = parser(ctx, *_pos); \
+    if (_result) *_pos = _result->end; \
+    _result; })
+
+size_t match_word(const char **out, const char *word) {
+    const char *pos = *out;
+    spaces(&pos);
+    if (!match(&pos, word) || is_xid_continue_next(pos))
+        return 0;
+
+    *out = pos;
+    return strlen(word);
+}
+
+const char *get_word(const char **inout) {
+    const char *word = *inout;
+    spaces(&word);
+    const uint8_t *pos = (const uint8_t*)word;
+    ucs4_t point;
+    pos = u8_next(&point, pos);
+    if (!uc_is_property_xid_start(point) && point != '_')
+        return NULL;
+
+    for (const uint8_t *next; (next = u8_next(&point, pos)); pos = next) {
+        if (!uc_is_property_xid_continue(point))
+            break;
+    }
+    *inout = (const char*)pos;
+    return GC_strndup(word, (size_t)((const char*)pos - word));
+}
+
+const char *get_id(const char **inout) {
+    const char *pos = *inout;
+    const char *word = get_word(&pos);
+    if (!word) return word;
+    for (int i = 0; keywords[i]; i++)
+        if (strcmp(word, keywords[i]) == 0)
+            return NULL;
+    *inout = pos;
+    return word;
+}
+
+bool comment(const char **pos) {
+    if ((*pos)[0] == '#') {
+        *pos += strcspn(*pos, "\r\n");
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool indent(parse_ctx_t *ctx, const char **out) {
+    const char *pos = *out;
+    int64_t starting_indent = get_indent(ctx, pos);
+    whitespace(&pos);
+    const char *next_line = get_line(ctx->file, get_line_number(ctx->file, pos));
+    if (next_line <= *out)
+        return false;
+
+    if (get_indent(ctx, next_line) != starting_indent + SPACES_PER_INDENT)
+        return false;
+
+    *out = next_line + strspn(next_line, " \t");
+    return true;
+}
+
+bool newline_with_indentation(const char **out, int64_t target) {
+    const char *pos = *out;
+    if (*pos == '\r') ++pos;
+    if (*pos != '\n') return false;
+    ++pos;
+    if (*pos == '\r' || *pos == '\n' || *pos == '\0') {
+        // Empty line
+        *out = pos;
+        return true;
+    }
+
+    if (*pos == ' ') {
+        if ((int64_t)strspn(pos, " ") >= target) {
+            *out = pos + target;
+            return true;
+        }
+    } else if ((int64_t)strspn(pos, "\t") * SPACES_PER_INDENT >= target) {
+        *out = pos + target / SPACES_PER_INDENT;
+        return true;
+    }
+    return false;
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////     AST-based parsers    /////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+PARSER(parse_parens) {
+    const char *start = pos;
+    spaces(&pos);
+    if (!match(&pos, "(")) return NULL;
+    whitespace(&pos);
+    ast_t *expr = optional(ctx, &pos, parse_extended_expr);
+    if (!expr) return NULL;
+    whitespace(&pos);
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this expression");
+
+    // Update the span to include the parens:
+    return new(ast_t, .file=(ctx)->file, .start=start, .end=pos,
+               .tag=expr->tag, .__data=expr->__data);
+}
+
+PARSER(parse_int) {
+    const char *start = pos;
+    (void)match(&pos, "-");
+    if (!isdigit(*pos)) return NULL;
+    if (match(&pos, "0x")) { // Hex
+        pos += strspn(pos, "0123456789abcdefABCDEF_");
+    } else if (match(&pos, "0b")) { // Binary
+        pos += strspn(pos, "01_");
+    } else if (match(&pos, "0o")) { // Octal
+        pos += strspn(pos, "01234567_");
+    } else { // Decimal
+        pos += strspn(pos, "0123456789_");
+    }
+    char *str = GC_MALLOC_ATOMIC((size_t)(pos - start) + 1);
+    memset(str, 0, (size_t)(pos - start) + 1);
+    for (char *src = (char*)start, *dest = str; src < pos; ++src) {
+        if (*src != '_') *(dest++) = *src;
+    }
+
+    if (match(&pos, "e") || match(&pos, "f")) // floating point literal
+        return NULL;
+
+    if (match(&pos, "%")) {
+        double n = strtod(str, NULL) / 100.;
+        return NewAST(ctx->file, start, pos, Num, .n=n);
+    } else if (match(&pos, "deg")) {
+        double n = strtod(str, NULL) * RADIANS_PER_DEGREE;
+        return NewAST(ctx->file, start, pos, Num, .n=n);
+    }
+
+    return NewAST(ctx->file, start, pos, Int, .str=str);
+}
+
+PARSER(parse_moment) {
+    const char *start = pos;
+    bool negative = match(&pos, "-");
+    if (!isdigit(*pos)) return NULL;
+
+    struct tm info = {.tm_isdst=-1};
+    char *after = strptime(pos, "%Y-%m-%d", &info);
+    if (!after) return NULL;
+    if (negative) info.tm_year = -(info.tm_year + 1900) - 1900;
+    pos = after;
+    if (match(&pos, "T") || spaces(&pos) >= 1) {
+        after = strptime(pos, "%H:%M", &info);
+        if (after) {
+            pos = after;
+            after = strptime(pos, ":%S", &info);
+            if (after) pos = after;
+            // TODO parse nanoseconds
+        }
+    }
+
+    const char *before_spaces = pos;
+    spaces(&pos);
+    Moment_t moment;
+    if (match(&pos, "[")) {
+        size_t tz_len = strcspn(pos, "\r\n]");
+        const char *tz = heap_strf("%.*s", tz_len, pos);
+        // TODO: check that tz is a valid timezone
+        pos += tz_len;
+        expect_closing(ctx, &pos, "]", "I wasn't able to parse the rest of this moment timezone");
+        const char *old_tz = getenv("TZ");
+        setenv("TZ", tz, 1);
+        tzset();
+        moment = (Moment_t){.tv_sec=mktime(&info)};
+        if (old_tz) setenv("TZ", old_tz, 1);
+        else unsetenv("TZ");
+    } else if (*pos == 'Z' || *pos == '-' || *pos == '+') {
+        after = strptime(pos, "%z", &info);
+        if (after) {
+            pos = after;
+            long offset = info.tm_gmtoff; // Need to cache this because mktime() mutates it to local timezone >:(
+            time_t t = mktime(&info);
+            moment = (Moment_t){.tv_sec=t + offset - info.tm_gmtoff};
+        } else {
+            moment = (Moment_t){.tv_sec=mktime(&info)};
+        }
+    } else {
+        pos = before_spaces;
+        moment = (Moment_t){.tv_sec=mktime(&info)};
+    }
+
+    return NewAST(ctx->file, start, pos, Moment, .moment=moment);
+}
+
+type_ast_t *parse_table_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match(&pos, "{")) return NULL;
+    whitespace(&pos);
+    type_ast_t *key_type = parse_type(ctx, pos);
+    if (!key_type) return NULL;
+    pos = key_type->end;
+    whitespace(&pos);
+    type_ast_t *value_type = NULL;
+    ast_t *default_value = NULL;
+    if (match(&pos, ",")) {
+        value_type = expect(ctx, start, &pos, parse_type, "I couldn't parse the rest of this table type");
+    } else if (match(&pos, "=")) {
+        default_value = expect(ctx, start, &pos, parse_extended_expr, "I couldn't parse the rest of this table type");
+    } else {
+        return NULL;
+    }
+    whitespace(&pos);
+    expect_closing(ctx, &pos, "}", "I wasn't able to parse the rest of this table type");
+    return NewTypeAST(ctx->file, start, pos, TableTypeAST, .key=key_type, .value=value_type, .default_value=default_value);
+}
+
+type_ast_t *parse_set_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match(&pos, "{")) return NULL;
+    whitespace(&pos);
+    type_ast_t *item_type = parse_type(ctx, pos);
+    if (!item_type) return NULL;
+    pos = item_type->end;
+    whitespace(&pos);
+    if (match(&pos, ",")) return NULL;
+    expect_closing(ctx, &pos, "}", "I wasn't able to parse the rest of this set type");
+    return NewTypeAST(ctx->file, start, pos, SetTypeAST, .item=item_type);
+}
+
+type_ast_t *parse_func_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match_word(&pos, "func")) return NULL;
+    spaces(&pos);
+    if (!match(&pos, "(")) return NULL;
+    arg_ast_t *args = parse_args(ctx, &pos);
+    spaces(&pos);
+    type_ast_t *ret = match(&pos, "->") ? optional(ctx, &pos, parse_type) : NULL;
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this function type");
+    return NewTypeAST(ctx->file, start, pos, FunctionTypeAST, .args=args, .ret=ret);
+}
+
+type_ast_t *parse_array_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match(&pos, "[")) return NULL;
+    type_ast_t *type = expect(ctx, start, &pos, parse_type,
+                             "I couldn't parse an array item type after this point");
+    expect_closing(ctx, &pos, "]", "I wasn't able to parse the rest of this array type");
+    return NewTypeAST(ctx->file, start, pos, ArrayTypeAST, .item=type);
+}
+
+type_ast_t *parse_pointer_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    bool is_stack;
+    if (match(&pos, "@"))
+        is_stack = false;
+    else if (match(&pos, "&"))
+        is_stack = true;
+    else
+        return NULL;
+
+    spaces(&pos);
+    type_ast_t *type = expect(ctx, start, &pos, parse_non_optional_type,
+                              "I couldn't parse a pointer type after this point");
+    type_ast_t *ptr_type = NewTypeAST(ctx->file, start, pos, PointerTypeAST, .pointed=type, .is_stack=is_stack);
+    spaces(&pos);
+    while (match(&pos, "?"))
+        ptr_type = NewTypeAST(ctx->file, start, pos, OptionalTypeAST, .type=ptr_type);
+    return ptr_type;
+}
+
+type_ast_t *parse_mutexed_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match_word(&pos, "mutexed")) return NULL;
+    spaces(&pos);
+    if (!match(&pos, "(")) return NULL;
+    spaces(&pos);
+    type_ast_t *mutexed = expect(ctx, start, &pos, parse_type,
+                                 "I couldn't parse a mutexed type after this point");
+    spaces(&pos);
+    if (!match(&pos, ")")) return NULL;
+    return NewTypeAST(ctx->file, start, pos, MutexedTypeAST, .type=mutexed);
+}
+
+type_ast_t *parse_type_name(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    const char *id = get_id(&pos);
+    if (!id) return NULL;
+    for (;;) {
+        const char *next = pos;
+        spaces(&next);
+        if (!match(&next, ".")) break;
+        const char *next_id = get_id(&next);
+        if (!next_id) break;
+        id = heap_strf("%s.%s", id, next_id);
+        pos = next;
+    }
+    return NewTypeAST(ctx->file, start, pos, VarTypeAST, .name=id);
+}
+
+type_ast_t *parse_non_optional_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    type_ast_t *type = NULL;
+    bool success = (false
+        || (type=parse_pointer_type(ctx, pos))
+        || (type=parse_array_type(ctx, pos))
+        || (type=parse_table_type(ctx, pos))
+        || (type=parse_set_type(ctx, pos))
+        || (type=parse_type_name(ctx, pos))
+        || (type=parse_func_type(ctx, pos))
+        || (type=parse_mutexed_type(ctx, pos))
+    );
+    if (!success && match(&pos, "(")) {
+        whitespace(&pos);
+        type = optional(ctx, &pos, parse_type);
+        if (!type) return NULL;
+        whitespace(&pos);
+        expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this type");
+        type->start = start;
+        type->end = pos;
+    }
+
+    return type;
+}
+
+type_ast_t *parse_type(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    type_ast_t *type = parse_non_optional_type(ctx, pos);
+    if (!type) return NULL;
+    pos = type->end;
+    spaces(&pos);
+    while (match(&pos, "?"))
+        type = NewTypeAST(ctx->file, start, pos, OptionalTypeAST, .type=type);
+    return type;
+}
+
+PARSER(parse_num) {
+    const char *start = pos;
+    bool negative = match(&pos, "-");
+    if (!isdigit(*pos) && *pos != '.') return NULL;
+    else if (*pos == '.' && !isdigit(pos[1])) return NULL;
+
+    size_t len = strspn(pos, "0123456789_");
+    if (strncmp(pos+len, "..", 2) == 0)
+        return NULL;
+    else if (pos[len] == '.')
+        len += 1 + strspn(pos + len + 1, "0123456789");
+    else if (pos[len] != 'e' && pos[len] != 'f' && pos[len] != '%')
+        return NULL;
+    if (pos[len] == 'e') {
+        len += 1;
+        if (pos[len] == '-')
+            len += 1;
+        len += strspn(pos + len, "0123456789_");
+    }
+    char *buf = GC_MALLOC_ATOMIC(len+1);
+    memset(buf, 0, len+1);
+    for (char *src = (char*)pos, *dest = buf; src < pos+len; ++src) {
+        if (*src != '_') *(dest++) = *src;
+    }
+    double d = strtod(buf, NULL);
+    pos += len;
+
+    if (negative) d *= -1;
+
+    if (match(&pos, "%"))
+        d /= 100.;
+    else if (match(&pos, "deg"))
+        d *= RADIANS_PER_DEGREE;
+
+    return NewAST(ctx->file, start, pos, Num, .n=d);
+}
+
+static INLINE bool match_separator(const char **pos) { // Either comma or newline
+    const char *p = *pos;
+    int separators = 0;
+    for (;;) {
+        if (some_of(&p, "\r\n,"))
+            ++separators;
+        else if (!comment(&p) && !some_of(&p, " \t"))
+            break;
+    }
+    if (separators > 0) {
+        *pos = p;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+PARSER(parse_array) {
+    const char *start = pos;
+    if (!match(&pos, "[")) return NULL;
+
+    whitespace(&pos);
+
+    ast_list_t *items = NULL;
+    type_ast_t *item_type = NULL;
+    if (match(&pos, ":")) {
+        whitespace(&pos);
+        item_type = expect(ctx, pos-1, &pos, parse_type, "I couldn't parse a type for this array");
+        whitespace(&pos);
+        match(&pos, ",");
+        whitespace(&pos);
+    }
+
+    for (;;) {
+        ast_t *item = optional(ctx, &pos, parse_extended_expr);
+        if (!item) break;
+        ast_t *suffixed = parse_comprehension_suffix(ctx, item);
+        while (suffixed) {
+            item = suffixed;
+            pos = suffixed->end;
+            suffixed = parse_comprehension_suffix(ctx, item);
+        }
+        items = new(ast_list_t, .ast=item, .next=items);
+        if (!match_separator(&pos))
+            break;
+    }
+    whitespace(&pos);
+    expect_closing(ctx, &pos, "]", "I wasn't able to parse the rest of this array");
+
+    if (!item_type && !items)
+        parser_err(ctx, start, pos, "Empty arrays must specify what type they would contain (e.g. [:Int])");
+
+    REVERSE_LIST(items);
+    return NewAST(ctx->file, start, pos, Array, .item_type=item_type, .items=items);
+}
+
+PARSER(parse_table) {
+    const char *start = pos;
+    if (!match(&pos, "{")) return NULL;
+
+    whitespace(&pos);
+
+    ast_list_t *entries = NULL;
+    type_ast_t *key_type = NULL, *value_type = NULL;
+    ast_t *default_value = NULL;
+    if (match(&pos, ":")) {
+        whitespace(&pos);
+        key_type = expect(ctx, pos-1, &pos, parse_type, "I couldn't parse a key type for this table");
+        whitespace(&pos);
+        if (match(&pos, ",")) {
+            value_type = expect(ctx, pos-1, &pos, parse_type, "I couldn't parse the value type for this table");
+        } else if (match(&pos, "=")) {
+            default_value = expect(ctx, pos-1, &pos, parse_extended_expr, "I couldn't parse the default value for this table");
+        } else {
+            return NULL;
+        }
+        whitespace(&pos);
+        match(&pos, ",");
+    }
+
+    for (;;) {
+        const char *entry_start = pos;
+        ast_t *key = optional(ctx, &pos, parse_extended_expr);
+        if (!key) break;
+        whitespace(&pos);
+        if (!match(&pos, "=")) return NULL;
+        ast_t *value = expect(ctx, pos-1, &pos, parse_expr, "I couldn't parse the value for this table entry");
+        ast_t *entry = NewAST(ctx->file, entry_start, pos, TableEntry, .key=key, .value=value);
+        ast_t *suffixed = parse_comprehension_suffix(ctx, entry);
+        while (suffixed) {
+            entry = suffixed;
+            pos = suffixed->end;
+            suffixed = parse_comprehension_suffix(ctx, entry);
+        }
+        entries = new(ast_list_t, .ast=entry, .next=entries);
+        if (!match_separator(&pos))
+            break;
+    }
+
+    REVERSE_LIST(entries);
+
+    if (!key_type && !value_type && !entries)
+        return NULL;
+
+    whitespace(&pos);
+
+    ast_t *fallback = NULL;
+    if (match(&pos, ";")) {
+        for (;;) {
+            whitespace(&pos);
+            const char *attr_start = pos;
+            if (match_word(&pos, "fallback")) {
+                whitespace(&pos);
+                if (!match(&pos, "=")) parser_err(ctx, attr_start, pos, "I expected an '=' after 'fallback'");
+                if (fallback)
+                    parser_err(ctx, attr_start, pos, "This table already has a fallback");
+                fallback = expect(ctx, attr_start, &pos, parse_expr, "I expected a fallback table");
+            } else {
+                break;
+            }
+            whitespace(&pos);
+            if (!match(&pos, ";")) break;
+        }
+    }
+
+    whitespace(&pos);
+    expect_closing(ctx, &pos, "}", "I wasn't able to parse the rest of this table");
+
+    return NewAST(ctx->file, start, pos, Table, .key_type=key_type, .value_type=value_type,
+                  .default_value=default_value, .entries=entries, .fallback=fallback);
+}
+
+PARSER(parse_set) {
+    const char *start = pos;
+    if (!match(&pos, "{")) return NULL;
+
+    whitespace(&pos);
+
+    ast_list_t *items = NULL;
+    type_ast_t *item_type = NULL;
+    if (match(&pos, ":")) {
+        whitespace(&pos);
+        item_type = expect(ctx, pos-1, &pos, parse_type, "I couldn't parse a key type for this set");
+        whitespace(&pos);
+        if (match(&pos, ","))
+            return NULL;
+        whitespace(&pos);
+        match(&pos, ",");
+        whitespace(&pos);
+    }
+
+    for (;;) {
+        ast_t *item = optional(ctx, &pos, parse_extended_expr);
+        if (!item) break;
+        whitespace(&pos);
+        if (match(&pos, "=")) return NULL;
+        ast_t *suffixed = parse_comprehension_suffix(ctx, item);
+        while (suffixed) {
+            item = suffixed;
+            pos = suffixed->end;
+            suffixed = parse_comprehension_suffix(ctx, item);
+        }
+        items = new(ast_list_t, .ast=item, .next=items);
+        if (!match_separator(&pos))
+            break;
+    }
+
+    REVERSE_LIST(items);
+
+    if (!item_type && !items)
+        return NULL;
+
+    whitespace(&pos);
+    expect_closing(ctx, &pos, "}", "I wasn't able to parse the rest of this set");
+
+    return NewAST(ctx->file, start, pos, Set, .item_type=item_type, .items=items);
+}
+
+ast_t *parse_field_suffix(parse_ctx_t *ctx, ast_t *lhs) {
+    if (!lhs) return NULL;
+    const char *pos = lhs->end;
+    whitespace(&pos);
+    if (!match(&pos, ".")) return NULL;
+    if (*pos == '.') return NULL;
+    whitespace(&pos);
+    bool dollar = match(&pos, "$");
+    const char* field = get_id(&pos);
+    if (!field) return NULL;
+    if (dollar) field = heap_strf("$%s", field);
+    return NewAST(ctx->file, lhs->start, pos, FieldAccess, .fielded=lhs, .field=field);
+}
+
+ast_t *parse_optional_suffix(parse_ctx_t *ctx, ast_t *lhs) {
+    if (!lhs) return NULL;
+    const char *pos = lhs->end;
+    if (match(&pos, "?"))
+        return NewAST(ctx->file, lhs->start, pos, Optional, .value=lhs);
+    else
+        return NULL;
+}
+
+ast_t *parse_non_optional_suffix(parse_ctx_t *ctx, ast_t *lhs) {
+    if (!lhs) return NULL;
+    const char *pos = lhs->end;
+    if (match(&pos, "!"))
+        return NewAST(ctx->file, lhs->start, pos, NonOptional, .value=lhs);
+    else
+        return NULL;
+}
+
+PARSER(parse_reduction) {
+    const char *start = pos;
+    if (!match(&pos, "(")) return NULL;
+    
+    whitespace(&pos);
+    binop_e op = match_binary_operator(&pos);
+    if (op == BINOP_UNKNOWN) return NULL;
+
+    ast_t *key = NULL;
+    if (op == BINOP_MIN || op == BINOP_MAX) {
+        key = NewAST(ctx->file, pos, pos, Var, .name="$");
+        for (bool progress = true; progress; ) {
+            ast_t *new_term;
+            progress = (false
+                || (new_term=parse_index_suffix(ctx, key))
+                || (new_term=parse_field_suffix(ctx, key))
+                || (new_term=parse_method_call_suffix(ctx, key))
+                || (new_term=parse_fncall_suffix(ctx, key))
+                || (new_term=parse_optional_suffix(ctx, key))
+                || (new_term=parse_non_optional_suffix(ctx, key))
+                );
+            if (progress) key = new_term;
+        }
+        if (key->tag == Var) key = NULL;
+        else pos = key->end;
+    }
+
+    whitespace(&pos);
+    if (!match(&pos, ":")) return NULL;
+
+    ast_t *iter = optional(ctx, &pos, parse_extended_expr);
+    if (!iter) return NULL;
+    ast_t *suffixed = parse_comprehension_suffix(ctx, iter);
+    while (suffixed) {
+        iter = suffixed;
+        pos = suffixed->end;
+        suffixed = parse_comprehension_suffix(ctx, iter);
+    }
+
+    whitespace(&pos);
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this reduction");
+
+    return NewAST(ctx->file, start, pos, Reduction, .iter=iter, .op=op, .key=key);
+}
+
+ast_t *parse_index_suffix(parse_ctx_t *ctx, ast_t *lhs) {
+    if (!lhs) return NULL;
+    const char *start = lhs->start;
+    const char *pos = lhs->end;
+    spaces(&pos);
+    if (!match(&pos, "[")) return NULL;
+    whitespace(&pos);
+    ast_t *index = optional(ctx, &pos, parse_extended_expr);
+    whitespace(&pos);
+    bool unchecked = match(&pos, ";") && (spaces(&pos), match_word(&pos, "unchecked") != 0);
+    expect_closing(ctx, &pos, "]", "I wasn't able to parse the rest of this index");
+    return NewAST(ctx->file, start, pos, Index, .indexed=lhs, .index=index, .unchecked=unchecked);
+}
+
+ast_t *parse_comprehension_suffix(parse_ctx_t *ctx, ast_t *expr) {
+    // <expr> "for" [<index>,]<var> "in" <iter> ["if" <condition> | "unless" <condition>]
+    if (!expr) return NULL;
+    const char *start = expr->start;
+    const char *pos = expr->end;
+    whitespace(&pos);
+    if (!match_word(&pos, "for")) return NULL;
+
+    ast_list_t *vars = NULL;
+    for (;;) {
+        ast_t *var = optional(ctx, &pos, parse_var);
+        if (var)
+            vars = new(ast_list_t, .ast=var, .next=vars);
+
+        spaces(&pos);
+        if (!match(&pos, ","))
+            break;
+    }
+    REVERSE_LIST(vars);
+
+    expect_str(ctx, start, &pos, "in", "I expected an 'in' for this 'for'");
+    ast_t *iter = expect(ctx, start, &pos, parse_expr, "I expected an iterable value for this 'for'");
+    const char *next_pos = pos;
+    whitespace(&next_pos);
+    ast_t *filter = NULL;
+    if (match_word(&next_pos, "if")) {
+        pos = next_pos;
+        filter = expect(ctx, pos-2, &pos, parse_expr, "I expected a condition for this 'if'");
+    } else if (match_word(&next_pos, "unless")) {
+        pos = next_pos;
+        filter = expect(ctx, pos-2, &pos, parse_expr, "I expected a condition for this 'unless'");
+        filter = WrapAST(filter, Not, filter);
+    }
+    return NewAST(ctx->file, start, pos, Comprehension, .expr=expr, .vars=vars, .iter=iter, .filter=filter);
+}
+
+ast_t *parse_optional_conditional_suffix(parse_ctx_t *ctx, ast_t *stmt) {
+    // <statement> "if" <condition> | <statement> "unless" <condition>
+    if (!stmt) return stmt;
+    const char *start = stmt->start;
+    const char *pos = stmt->end;
+    if (match_word(&pos, "if")) {
+        ast_t *condition = expect(ctx, pos-2, &pos, parse_expr, "I expected a condition for this 'if'");
+        return NewAST(ctx->file, start, pos, If, .condition=condition, .body=stmt);
+    } else if (match_word(&pos, "unless")) {
+        ast_t *condition = expect(ctx, pos-2, &pos, parse_expr, "I expected a condition for this 'unless'");
+        condition = WrapAST(condition, Not, condition);
+        return NewAST(ctx->file, start, pos, If, .condition=condition, .body=stmt);
+    } else {
+        return stmt;
+    }
+}
+
+PARSER(parse_if) {
+    // "if" <condition> <body> ["else" <body>] | "unless" <condition> <body> ["else" <body>]
+    const char *start = pos;
+    int64_t starting_indent = get_indent(ctx, pos);
+
+    bool unless;
+    if (match_word(&pos, "if"))
+        unless = false;
+    else if (match_word(&pos, "unless"))
+        unless = true;
+    else
+        return NULL;
+
+    ast_t *condition = unless ? NULL : optional(ctx, &pos, parse_declaration);
+    if (!condition)
+        condition = expect(ctx, start, &pos, parse_expr, "I expected to find a condition for this 'if'");
+
+    if (unless)
+        condition = WrapAST(condition, Not, condition);
+
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'if' statement"); 
+
+    const char *tmp = pos;
+    whitespace(&tmp);
+    ast_t *else_body = NULL;
+    const char *else_start = pos;
+    if (get_indent(ctx, tmp) == starting_indent && match_word(&tmp, "else")) {
+        pos = tmp;
+        spaces(&pos);
+        else_body = optional(ctx, &pos, parse_if);
+        if (!else_body)
+            else_body = expect(ctx, else_start, &pos, parse_block, "I expected a body for this 'else'"); 
+    }
+    return NewAST(ctx->file, start, pos, If, .condition=condition, .body=body, .else_body=else_body);
+}
+
+PARSER(parse_when) {
+    // when <expr> (is var : Tag <body>)* [else <body>]
+    const char *start = pos;
+    int64_t starting_indent = get_indent(ctx, pos);
+
+    if (!match_word(&pos, "when"))
+        return NULL;
+
+    ast_t *subject = optional(ctx, &pos, parse_declaration);
+    if (!subject) subject = expect(ctx, start, &pos, parse_expr,
+                                   "I expected to find an expression for this 'when'");
+
+    when_clause_t *clauses = NULL;
+    const char *tmp = pos;
+    whitespace(&tmp);
+    while (get_indent(ctx, tmp) == starting_indent && match_word(&tmp, "is")) {
+        pos = tmp;
+        spaces(&pos);
+        ast_t *pattern = expect(ctx, start, &pos, parse_expr, "I expected a pattern to match here");
+        spaces(&pos);
+        tmp = pos;
+        if (!match(&tmp, ":"))
+            parser_err(ctx, tmp, tmp, "I expected a colon ':' after this clause");
+        ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'when' clause"); 
+        clauses = new(when_clause_t, .pattern=pattern, .body=body, .next=clauses);
+        tmp = pos;
+        whitespace(&tmp);
+    }
+    REVERSE_LIST(clauses);
+
+    ast_t *else_body = NULL;
+    const char *else_start = pos;
+    if (get_indent(ctx, tmp) == starting_indent && match_word(&tmp, "else")) {
+        pos = tmp;
+        else_body = expect(ctx, else_start, &pos, parse_block, "I expected a body for this 'else'"); 
+    }
+    return NewAST(ctx->file, start, pos, When, .subject=subject, .clauses=clauses, .else_body=else_body);
+}
+
+PARSER(parse_for) {
+    // for [k,] v in iter [<indent>] body
+    const char *start = pos;
+    if (!match_word(&pos, "for")) return NULL;
+    int64_t starting_indent = get_indent(ctx, pos);
+    spaces(&pos);
+    ast_list_t *vars = NULL;
+    for (;;) {
+        ast_t *var = optional(ctx, &pos, parse_var);
+        if (var)
+            vars = new(ast_list_t, .ast=var, .next=vars);
+
+        spaces(&pos);
+        if (!match(&pos, ","))
+            break;
+    }
+
+    spaces(&pos);
+    expect_str(ctx, start, &pos, "in", "I expected an 'in' for this 'for'");
+
+    ast_t *iter = expect(ctx, start, &pos, parse_expr, "I expected an iterable value for this 'for'");
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'for'"); 
+
+    const char *else_start = pos;
+    whitespace(&else_start);
+    ast_t *empty = NULL;
+    if (match_word(&else_start, "else") && get_indent(ctx, else_start) == starting_indent) {
+        pos = else_start;
+        empty = expect(ctx, pos, &pos, parse_block, "I expected a body for this 'else'");
+    }
+    REVERSE_LIST(vars);
+    return NewAST(ctx->file, start, pos, For, .vars=vars, .iter=iter, .body=body, .empty=empty);
+}
+
+PARSER(parse_do) {
+    // [do_begin: [<indent>] block] [do_end: [<indent>] block] do: [<indent>] body
+    const char *start = pos;
+    int64_t starting_indent = get_indent(ctx, pos);
+    ast_t *begin = NULL, *end = NULL;
+    if (match_word(&pos, "do_begin"))
+        begin = optional(ctx, &pos, parse_block);
+
+    const char *tmp = pos;
+    whitespace(&tmp);
+    if (get_indent(ctx, tmp) == starting_indent && match_word(&tmp, "do_end")) {
+        pos = tmp;
+        end = optional(ctx, &pos, parse_block);
+    }
+
+    tmp = pos;
+    whitespace(&tmp);
+    if (get_indent(ctx, tmp) == starting_indent && match_word(&tmp, "do")) {
+        pos = tmp;
+        ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'do'"); 
+        if (begin && end) {
+            return NewAST(ctx->file, start, pos, Block,
+                          .statements=new(ast_list_t, .ast=begin,
+                                          .next=new(ast_list_t, .ast=WrapAST(end, Defer, .body=end),
+                                                    .next=new(ast_list_t, .ast=body))));
+        } else if (begin) {
+            return NewAST(ctx->file, start, pos, Block,
+                          .statements=new(ast_list_t, .ast=begin,
+                                          .next=new(ast_list_t, .ast=body)));
+        } else if (end) {
+            return NewAST(ctx->file, start, pos, Block,
+                          .statements=new(ast_list_t, .ast=WrapAST(end, Defer, .body=end),
+                                          .next=new(ast_list_t, .ast=body)));
+        } else {
+            return NewAST(ctx->file, start, pos, Block, .statements=Match(body, Block)->statements);
+        }
+    } else {
+        return NULL;
+    }
+}
+
+PARSER(parse_while) {
+    // while condition: [<indent>] body
+    const char *start = pos;
+    if (!match_word(&pos, "while")) return NULL;
+
+    const char *tmp = pos;
+    // Shorthand form: `while when ...`
+    if (match_word(&tmp, "when")) {
+        ast_t *when = expect(ctx, start, &pos, parse_when, "I expected a 'when' block after this");
+        if (!when->__data.When.else_body) when->__data.When.else_body = NewAST(ctx->file, pos, pos, Stop);
+        return NewAST(ctx->file, start, pos, While, .body=when);
+    }
+    ast_t *condition = expect(ctx, start, &pos, parse_expr, "I don't see a viable condition for this 'while'");
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'while'"); 
+    return NewAST(ctx->file, start, pos, While, .condition=condition, .body=body);
+}
+
+PARSER(parse_repeat) {
+    // repeat: [<indent>] body
+    const char *start = pos;
+    if (!match_word(&pos, "repeat")) return NULL;
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'repeat'"); 
+    return NewAST(ctx->file, start, pos, Repeat, .body=body);
+}
+
+PARSER(parse_heap_alloc) {
+    const char *start = pos;
+    if (!match(&pos, "@")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term_no_suffix, "I expected an expression for this '@'");
+
+    for (;;) {
+        ast_t *new_term;
+        if ((new_term=parse_index_suffix(ctx, val))
+            || (new_term=parse_fncall_suffix(ctx, val))
+            || (new_term=parse_field_suffix(ctx, val))) {
+            val = new_term;
+        } else break;
+    }
+    pos = val->end;
+
+    ast_t *ast = NewAST(ctx->file, start, pos, HeapAllocate, .value=val);
+    for (;;) {
+        ast_t *next = parse_optional_suffix(ctx, ast);
+        if (!next) next = parse_non_optional_suffix(ctx, ast);
+        if (!next) break;
+        ast = next;
+    }
+    return ast;
+}
+
+PARSER(parse_stack_reference) {
+    const char *start = pos;
+    if (!match(&pos, "&")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term_no_suffix, "I expected an expression for this '&'");
+
+    for (;;) {
+        ast_t *new_term;
+        if ((new_term=parse_index_suffix(ctx, val))
+            || (new_term=parse_fncall_suffix(ctx, val))
+            || (new_term=parse_field_suffix(ctx, val))) {
+            val = new_term;
+        } else break;
+    }
+    pos = val->end;
+
+    ast_t *ast = NewAST(ctx->file, start, pos, StackReference, .value=val);
+    for (;;) {
+        ast_t *next = parse_optional_suffix(ctx, ast);
+        if (!next) next = parse_non_optional_suffix(ctx, ast);
+        if (!next) break;
+        ast = next;
+    }
+    return ast;
+}
+
+PARSER(parse_mutexed) {
+    const char *start = pos;
+    if (!match_word(&pos, "mutexed")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term, "I expected an expression for this 'mutexed'");
+    return NewAST(ctx->file, start, pos, Mutexed, .value=val);
+}
+
+PARSER(parse_holding) {
+    const char *start = pos;
+    if (!match_word(&pos, "holding")) return NULL;
+    spaces(&pos);
+    ast_t *mutexed = expect(ctx, start, &pos, parse_expr, "I expected an expression for this 'holding'");
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a block to be here");
+    return NewAST(ctx->file, start, pos, Holding, .mutexed=mutexed, .body=body);
+}
+
+PARSER(parse_not) {
+    const char *start = pos;
+    if (!match_word(&pos, "not")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term, "I expected an expression for this 'not'");
+    return NewAST(ctx->file, start, pos, Not, .value=val);
+}
+
+PARSER(parse_negative) {
+    const char *start = pos;
+    if (!match(&pos, "-")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term, "I expected an expression for this '-'");
+    return NewAST(ctx->file, start, pos, Negative, .value=val);
+}
+
+PARSER(parse_bool) {
+    const char *start = pos;
+    if (match_word(&pos, "yes"))
+        return NewAST(ctx->file, start, pos, Bool, .b=true);
+    else if (match_word(&pos, "no"))
+        return NewAST(ctx->file, start, pos, Bool, .b=false);
+    else
+        return NULL;
+}
+
+PARSER(parse_text) {
+    // ('"' ... '"' / "'" ... "'" / "`" ... "`")
+    // "$" [name] [interp-char] quote-char ... close-quote
+    const char *start = pos;
+    const char *lang = NULL;
+
+    // Escape sequence, e.g. \r\n
+    if (*pos == '\\') {
+        CORD cord = CORD_EMPTY;
+        do {
+            const char *c = unescape(ctx, &pos);
+            cord = CORD_cat(cord, c);
+            // cord = CORD_cat_char(cord, c);
+        } while (*pos == '\\');
+        return NewAST(ctx->file, start, pos, TextLiteral, .cord=cord);
+    }
+
+    char open_quote, close_quote, open_interp = '$';
+    if (match(&pos, "\"")) { // Double quote
+        open_quote = '"', close_quote = '"', open_interp = '$';
+    } else if (match(&pos, "`")) { // Backtick
+        open_quote = '`', close_quote = '`', open_interp = '$';
+    } else if (match(&pos, "'")) { // Single quote
+        open_quote = '\'', close_quote = '\'', open_interp = '\x03';
+    } else if (match(&pos, "$")) { // Customized strings
+        lang = get_id(&pos);
+        // $"..." or $@"...."
+        static const char *interp_chars = "~!@#$%^&*+=\\?";
+        if (match(&pos, "$")) { // Disable interpolation with $
+            open_interp = '\x03';
+        } else if (strchr(interp_chars, *pos)) {
+            open_interp = *pos;
+            ++pos;
+        } else if (*pos == '(') {
+            open_interp = '@'; // For shell commands
+        }
+        static const char *quote_chars = "\"'`|/;([{<";
+        if (!strchr(quote_chars, *pos))
+            parser_err(ctx, pos, pos+1, "This is not a valid string quotation character. Valid characters are: \"'`|/;([{<");
+        open_quote = *pos;
+        ++pos;
+        close_quote = closing[(int)open_quote] ? closing[(int)open_quote] : open_quote;
+
+        if (!lang && (open_quote == '/' || open_quote == '|'))
+            lang = "Pattern";
+    } else {
+        return NULL;
+    }
+
+    int64_t starting_indent = get_indent(ctx, pos);
+    int64_t string_indent = starting_indent + SPACES_PER_INDENT;
+
+    ast_list_t *chunks = NULL;
+    CORD chunk = CORD_EMPTY;
+    const char *chunk_start = pos;
+    int depth = 1;
+    bool leading_newline = false;
+    for (; pos < ctx->file->text + ctx->file->len && depth > 0; ) {
+        if (*pos == open_interp) { // Interpolation
+            const char *interp_start = pos;
+            if (chunk) {
+                ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .cord=chunk);
+                chunks = new(ast_list_t, .ast=literal, .next=chunks);
+                chunk = NULL;
+            }
+            ++pos;
+            ast_t *interp;
+            if (*pos == ' ' || *pos == '\t')
+                parser_err(ctx, pos, pos+1, "Whitespace is not allowed before an interpolation here");
+            interp = expect(ctx, interp_start, &pos, parse_term_no_suffix, "I expected an interpolation term here");
+            chunks = new(ast_list_t, .ast=interp, .next=chunks);
+            chunk_start = pos;
+        } else if (!leading_newline && *pos == open_quote && closing[(int)open_quote]) { // Nested pair begin
+            if (get_indent(ctx, pos) == starting_indent) {
+                ++depth;
+            }
+            chunk = CORD_cat_char(chunk, *pos);
+            ++pos;
+        } else if (!leading_newline && *pos == close_quote) { // Nested pair end
+            if (get_indent(ctx, pos) == starting_indent) {
+                --depth;
+                if (depth == 0)
+                    break;
+            }
+            chunk = CORD_cat_char(chunk, *pos);
+            ++pos;
+        } else if (newline_with_indentation(&pos, string_indent)) { // Newline
+            if (!leading_newline && !(chunk || chunks)) {
+                leading_newline = true;
+            } else {
+                chunk = CORD_cat_char(chunk, '\n');
+            }
+        } else if (newline_with_indentation(&pos, starting_indent)) { // Line continuation (..)
+            if (*pos == close_quote) {
+                break;
+            } else if (some_of(&pos, ".") >= 2) {
+                // Multi-line split
+                continue;
+            } else {
+                parser_err(ctx, pos, strchrnul(pos, '\n'), "This multi-line string should be either indented or have '..' at the front");
+            }
+        } else { // Plain character
+            chunk = CORD_cat_char(chunk, *pos);
+            ++pos;
+        }
+    }
+
+    if (chunk) {
+        ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .cord=chunk);
+        chunks = new(ast_list_t, .ast=literal, .next=chunks);
+        chunk = NULL;
+    }
+
+    REVERSE_LIST(chunks);
+    expect_closing(ctx, &pos, (char[]){close_quote, 0}, "I was expecting a '%c' to finish this string", close_quote);
+    return NewAST(ctx->file, start, pos, TextJoin, .lang=lang, .children=chunks);
+}
+
+PARSER(parse_path) {
+    // "(" ("~/" / "./" / "../" / "/") ... ")"
+    const char *start = pos;
+
+    if (!match(&pos, "("))
+        return NULL;
+
+    if (!(*pos == '~' || *pos == '.' || *pos == '/'))
+        return NULL;
+
+    const char *path_start = pos;
+    size_t len = 1;
+    int paren_depth = 1;
+    while (pos + len < ctx->file->text + ctx->file->len - 1) {
+        if (pos[len] == '\\') {
+            len += 2;
+            continue;
+        } else if (pos[len] == '(') {
+            paren_depth += 1;
+        } else if (pos[len] == ')') {
+            paren_depth -= 1;
+            if (paren_depth <= 0) break;
+        } else if (pos[len] == '\r' || pos[len] == '\n') {
+            parser_err(ctx, path_start, &pos[len-1], "This path was not closed");
+        }
+        len += 1;
+    }
+    pos += len + 1;
+    char *path = heap_strf("%.*s", (int)len, path_start);
+    for (char *src = path, *dest = path; ; ) {
+        if (src[0] == '\\') {
+            *(dest++) = src[1];
+            src += 2;
+        } else if (*src) {
+            *(dest++) = *(src++);
+        } else {
+            *(dest++) = '\0';
+            break;
+        }
+    }
+    return NewAST(ctx->file, start, pos, Path, .path=path);
+}
+
+PARSER(parse_pass) {
+    const char *start = pos;
+    return match_word(&pos, "pass") ? NewAST(ctx->file, start, pos, Pass) : NULL;
+}
+
+PARSER(parse_defer) {
+    const char *start = pos;
+    if (!match_word(&pos, "defer")) return NULL;
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a block to be deferred here");
+    return NewAST(ctx->file, start, pos, Defer, .body=body);
+}
+
+PARSER(parse_skip) {
+    const char *start = pos;
+    if (!match_word(&pos, "skip")) return NULL;
+    const char *target;
+    if (match_word(&pos, "for")) target = "for";
+    else if (match_word(&pos, "while")) target = "while";
+    else target = get_id(&pos);
+    ast_t *skip = NewAST(ctx->file, start, pos, Skip, .target=target);
+    skip = parse_optional_conditional_suffix(ctx, skip);
+    return skip;
+}
+
+PARSER(parse_stop) {
+    const char *start = pos;
+    if (!match_word(&pos, "stop")) return NULL;
+    const char *target;
+    if (match_word(&pos, "for")) target = "for";
+    else if (match_word(&pos, "while")) target = "while";
+    else target = get_id(&pos);
+    ast_t *stop = NewAST(ctx->file, start, pos, Stop, .target=target);
+    stop = parse_optional_conditional_suffix(ctx, stop);
+    return stop;
+}
+
+PARSER(parse_return) {
+    const char *start = pos;
+    if (!match_word(&pos, "return")) return NULL;
+    ast_t *value = optional(ctx, &pos, parse_expr);
+    ast_t *ret = NewAST(ctx->file, start, pos, Return, .value=value);
+    ret = parse_optional_conditional_suffix(ctx, ret);
+    return ret;
+}
+
+PARSER(parse_lambda) {
+    const char *start = pos;
+    if (!match_word(&pos, "func"))
+        return NULL;
+    spaces(&pos);
+    if (!match(&pos, "("))
+        return NULL;
+    arg_ast_t *args = parse_args(ctx, &pos);
+    spaces(&pos);
+    type_ast_t *ret = match(&pos, "->") ? optional(ctx, &pos, parse_type) : NULL;
+    spaces(&pos);
+    expect_closing(ctx, &pos, ")", "I was expecting a ')' to finish this anonymous function's arguments");
+    ast_t *body = optional(ctx, &pos, parse_block);
+    if (!body) body = NewAST(ctx->file, pos, pos, Block, .statements=NULL);
+    return NewAST(ctx->file, start, pos, Lambda, .id=ctx->next_lambda_id++, .args=args, .ret_type=ret, .body=body);
+}
+
+PARSER(parse_none) {
+    const char *start = pos;
+    if (!match_word(&pos, "none"))
+        return NULL;
+
+    const char *none_end = pos;
+    spaces(&pos);
+    if (!match(&pos, ":"))
+        return NewAST(ctx->file, start, none_end, None, .type=NULL);
+
+    spaces(&pos);
+    type_ast_t *type = parse_type(ctx, pos);
+    if (!type) return NULL;
+    return NewAST(ctx->file, start, type->end, None, .type=type);
+}
+
+PARSER(parse_deserialize) {
+    const char *start = pos;
+    if (!match_word(&pos, "deserialize"))
+        return NULL;
+
+    spaces(&pos);
+    expect_str(ctx, start, &pos, "(", "I expected arguments for this `deserialize` call");
+    whitespace(&pos);
+    ast_t *value = expect(ctx, start, &pos, parse_extended_expr, "I expected an expression here");
+    whitespace(&pos);
+    expect_str(ctx, start, &pos, "->", "I expected a `-> Type` for this `deserialize` call so I know what it deserializes to");
+    whitespace(&pos);
+    type_ast_t *type = expect(ctx, start, &pos, parse_type, "I couldn't parse the type for this deserialization");
+    whitespace(&pos);
+    expect_closing(ctx, &pos, ")", "I expected a closing ')' for this `deserialize` call");
+    return NewAST(ctx->file, start, pos, Deserialize, .value=value, .type=type);
+}
+
+PARSER(parse_var) {
+    const char *start = pos;
+    const char* name = get_id(&pos);
+    if (!name) return NULL;
+    return NewAST(ctx->file, start, pos, Var, .name=name);
+}
+
+PARSER(parse_term_no_suffix) {
+    spaces(&pos);
+    ast_t *term = NULL;
+    (void)(
+        false
+        || (term=parse_moment(ctx, pos)) // Must come before num/int
+        || (term=parse_none(ctx, pos))
+        || (term=parse_num(ctx, pos)) // Must come before int
+        || (term=parse_int(ctx, pos))
+        || (term=parse_negative(ctx, pos)) // Must come after num/int
+        || (term=parse_heap_alloc(ctx, pos))
+        || (term=parse_stack_reference(ctx, pos))
+        || (term=parse_bool(ctx, pos))
+        || (term=parse_text(ctx, pos))
+        || (term=parse_path(ctx, pos))
+        || (term=parse_lambda(ctx, pos))
+        || (term=parse_parens(ctx, pos))
+        || (term=parse_table(ctx, pos))
+        || (term=parse_set(ctx, pos))
+        || (term=parse_deserialize(ctx, pos))
+        || (term=parse_var(ctx, pos))
+        || (term=parse_array(ctx, pos))
+        || (term=parse_reduction(ctx, pos))
+        || (term=parse_pass(ctx, pos))
+        || (term=parse_defer(ctx, pos))
+        || (term=parse_skip(ctx, pos))
+        || (term=parse_stop(ctx, pos))
+        || (term=parse_return(ctx, pos))
+        || (term=parse_not(ctx, pos))
+        || (term=parse_mutexed(ctx, pos))
+        || (term=parse_extern(ctx, pos))
+        || (term=parse_inline_c(ctx, pos))
+        );
+    return term;
+}
+
+PARSER(parse_term) {
+    ast_t *term = parse_term_no_suffix(ctx, pos);
+    if (!term) return NULL;
+
+    for (bool progress = true; progress; ) {
+        ast_t *new_term;
+        progress = (false
+            || (new_term=parse_index_suffix(ctx, term))
+            || (new_term=parse_field_suffix(ctx, term))
+            || (new_term=parse_method_call_suffix(ctx, term))
+            || (new_term=parse_fncall_suffix(ctx, term))
+            || (new_term=parse_optional_suffix(ctx, term))
+            || (new_term=parse_non_optional_suffix(ctx, term))
+            );
+        if (progress) term = new_term;
+    }
+    return term;
+}
+
+ast_t *parse_method_call_suffix(parse_ctx_t *ctx, ast_t *self) {
+    if (!self) return NULL;
+
+    const char *start = self->start;
+    const char *pos = self->end;
+
+    if (!match(&pos, ":")) return NULL;
+    if (*pos == ' ') return NULL;
+    const char *fn = get_id(&pos);
+    if (!fn) return NULL;
+    spaces(&pos);
+    if (!match(&pos, "(")) return NULL;
+    whitespace(&pos);
+
+    arg_ast_t *args = NULL;
+    for (;;) {
+        const char *arg_start = pos;
+        const char *name = get_id(&pos);
+        whitespace(&pos);
+        if (!name || !match(&pos, "=")) {
+            name = NULL;
+            pos = arg_start;
+        }
+
+        ast_t *arg = optional(ctx, &pos, parse_expr);
+        if (!arg) {
+            if (name) parser_err(ctx, arg_start, pos, "I expected an argument here");
+            break;
+        }
+        args = new(arg_ast_t, .name=name, .value=arg, .next=args);
+        if (!match_separator(&pos))
+            break;
+    }
+    REVERSE_LIST(args);
+
+    whitespace(&pos);
+
+    if (!match(&pos, ")"))
+        parser_err(ctx, start, pos, "This parenthesis is unclosed");
+
+    return NewAST(ctx->file, start, pos, MethodCall, .self=self, .name=fn, .args=args);
+}
+
+ast_t *parse_fncall_suffix(parse_ctx_t *ctx, ast_t *fn) {
+    if (!fn) return NULL;
+
+    const char *start = fn->start;
+    const char *pos = fn->end;
+
+    if (!match(&pos, "(")) return NULL;
+
+    whitespace(&pos);
+
+    arg_ast_t *args = NULL;
+    for (;;) {
+        const char *arg_start = pos;
+        const char *name = get_id(&pos);
+        whitespace(&pos);
+        if (!name || !match(&pos, "=")) {
+            name = NULL;
+            pos = arg_start;
+        }
+
+        ast_t *arg = optional(ctx, &pos, parse_expr);
+        if (!arg) {
+            if (name)
+                parser_err(ctx, arg_start, pos, "I expected an argument here");
+            break;
+        }
+        args = new(arg_ast_t, .name=name, .value=arg, .next=args);
+        if (!match_separator(&pos))
+            break;
+    }
+
+    whitespace(&pos);
+
+    if (!match(&pos, ")"))
+        parser_err(ctx, start, pos, "This parenthesis is unclosed");
+
+    REVERSE_LIST(args);
+    return NewAST(ctx->file, start, pos, FunctionCall, .fn=fn, .args=args);
+}
+
+binop_e match_binary_operator(const char **pos)
+{
+    switch (**pos) {
+    case '+': {
+        *pos += 1;
+        return match(pos, "+") ? BINOP_CONCAT : BINOP_PLUS;
+    }
+    case '-': {
+        *pos += 1;
+        if ((*pos)[0] != ' ' && (*pos)[-2] == ' ') // looks like `fn -5`
+            return BINOP_UNKNOWN;
+        return BINOP_MINUS;
+    }
+    case '*': *pos += 1; return BINOP_MULT;
+    case '/': *pos += 1; return BINOP_DIVIDE;
+    case '^': *pos += 1; return BINOP_POWER;
+    case '<': {
+        *pos += 1;
+        if (match(pos, "=")) return BINOP_LE; // "<="
+        else if (match(pos, ">")) return BINOP_CMP; // "<>"
+        else if (match(pos, "<")) {
+            if (match(pos, "<"))
+                return BINOP_ULSHIFT; // "<<<"
+            return BINOP_LSHIFT; // "<<"
+        } else return BINOP_LT;
+    }
+    case '>': {
+        *pos += 1;
+        if (match(pos, "=")) return BINOP_GE; // ">="
+        if (match(pos, ">")) {
+            if (match(pos, ">"))
+                return BINOP_URSHIFT; // ">>>"
+            return BINOP_RSHIFT; // ">>"
+        }
+        return BINOP_GT;
+    }
+    default: {
+        if (match(pos, "!=")) return BINOP_NE;
+        else if (match(pos, "==") && **pos != '=') return BINOP_EQ;
+        else if (match_word(pos, "and")) return BINOP_AND;
+        else if (match_word(pos, "or")) return BINOP_OR;
+        else if (match_word(pos, "xor")) return BINOP_XOR;
+        else if (match_word(pos, "mod1")) return BINOP_MOD1;
+        else if (match_word(pos, "mod")) return BINOP_MOD;
+        else if (match_word(pos, "_min_")) return BINOP_MIN;
+        else if (match_word(pos, "_max_")) return BINOP_MAX;
+        else return BINOP_UNKNOWN;
+    }
+    }
+}
+
+static ast_t *parse_infix_expr(parse_ctx_t *ctx, const char *pos, int min_tightness) {
+    ast_t *lhs = optional(ctx, &pos, parse_term);
+    if (!lhs) return NULL;
+
+    int64_t starting_line = get_line_number(ctx->file, pos);
+    int64_t starting_indent = get_indent(ctx, pos);
+    spaces(&pos);
+    for (binop_e op; (op=match_binary_operator(&pos)) != BINOP_UNKNOWN && op_tightness[op] >= min_tightness; spaces(&pos)) {
+        ast_t *key = NULL;
+        if (op == BINOP_MIN || op == BINOP_MAX) {
+            key = NewAST(ctx->file, pos, pos, Var, .name="$");
+            for (bool progress = true; progress; ) {
+                ast_t *new_term;
+                progress = (false
+                    || (new_term=parse_index_suffix(ctx, key))
+                    || (new_term=parse_field_suffix(ctx, key))
+                    || (new_term=parse_method_call_suffix(ctx, key))
+                    || (new_term=parse_fncall_suffix(ctx, key))
+                    || (new_term=parse_optional_suffix(ctx, key))
+                    || (new_term=parse_non_optional_suffix(ctx, key))
+                    );
+                if (progress) key = new_term;
+            }
+            if (key->tag == Var) key = NULL;
+            else pos = key->end;
+        }
+
+        whitespace(&pos);
+        if (get_line_number(ctx->file, pos) != starting_line && get_indent(ctx, pos) < starting_indent)
+            parser_err(ctx, pos, strchrnul(pos, '\n'), "I expected this line to be at least as indented than the line above it");
+
+        ast_t *rhs = parse_infix_expr(ctx, pos, op_tightness[op] + 1);
+        if (!rhs) break;
+        pos = rhs->end;
+        
+        if (op == BINOP_MIN) {
+            return NewAST(ctx->file, lhs->start, rhs->end, Min, .lhs=lhs, .rhs=rhs, .key=key);
+        } else if (op == BINOP_MAX) {
+            return NewAST(ctx->file, lhs->start, rhs->end, Max, .lhs=lhs, .rhs=rhs, .key=key);
+        } else {
+            lhs = NewAST(ctx->file, lhs->start, rhs->end, BinaryOp, .lhs=lhs, .op=op, .rhs=rhs);
+        }
+    }
+    return lhs;
+}
+
+PARSER(parse_expr) {
+    return parse_infix_expr(ctx, pos, 0);
+}
+
+PARSER(parse_declaration) {
+    const char *start = pos;
+    ast_t *var = parse_var(ctx, pos);
+    if (!var) return NULL;
+    pos = var->end;
+    spaces(&pos);
+    if (!match(&pos, ":=")) return NULL;
+    spaces(&pos);
+    ast_t *val = optional(ctx, &pos, parse_extended_expr);
+    if (!val) {
+        if (optional(ctx, &pos, parse_use))
+            parser_err(ctx, start, pos, "'use' statements are only allowed at the top level of a file");
+        else
+            parser_err(ctx, pos, strchrnul(pos, '\n'), "This is not a valid expression");
+    }
+    return NewAST(ctx->file, start, pos, Declare, .var=var, .value=val);
+}
+
+PARSER(parse_update) {
+    const char *start = pos;
+    ast_t *lhs = optional(ctx, &pos, parse_expr);
+    if (!lhs) return NULL;
+    spaces(&pos);
+    binop_e op;
+    if (match(&pos, "+=")) op = BINOP_PLUS;
+    else if (match(&pos, "++=")) op = BINOP_CONCAT;
+    else if (match(&pos, "-=")) op = BINOP_MINUS;
+    else if (match(&pos, "*=")) op = BINOP_MULT;
+    else if (match(&pos, "/=")) op = BINOP_DIVIDE;
+    else if (match(&pos, "^=")) op = BINOP_POWER;
+    else if (match(&pos, "<<=")) op = BINOP_LSHIFT;
+    else if (match(&pos, "<<<=")) op = BINOP_ULSHIFT;
+    else if (match(&pos, ">>=")) op = BINOP_RSHIFT;
+    else if (match(&pos, ">>>=")) op = BINOP_URSHIFT;
+    else if (match(&pos, "and=")) op = BINOP_AND;
+    else if (match(&pos, "or=")) op = BINOP_OR;
+    else if (match(&pos, "xor=")) op = BINOP_XOR;
+    else return NULL;
+    ast_t *rhs = expect(ctx, start, &pos, parse_extended_expr, "I expected an expression here");
+    return NewAST(ctx->file, start, pos, UpdateAssign, .lhs=lhs, .rhs=rhs, .op=op);
+}
+
+PARSER(parse_assignment) {
+    const char *start = pos;
+    ast_list_t *targets = NULL;
+    for (;;) {
+        ast_t *lhs = optional(ctx, &pos, parse_term);
+        if (!lhs) break;
+        targets = new(ast_list_t, .ast=lhs, .next=targets);
+        spaces(&pos);
+        if (!match(&pos, ",")) break;
+        whitespace(&pos);
+    }
+
+    if (!targets) return NULL;
+
+    spaces(&pos);
+    if (!match(&pos, "=")) return NULL;
+    if (match(&pos, "=")) return NULL; // == comparison
+
+    ast_list_t *values = NULL;
+    for (;;) {
+        ast_t *rhs = optional(ctx, &pos, parse_extended_expr);
+        if (!rhs) break;
+        values = new(ast_list_t, .ast=rhs, .next=values);
+        spaces(&pos);
+        if (!match(&pos, ",")) break;
+        whitespace(&pos);
+    }
+
+    REVERSE_LIST(targets);
+    REVERSE_LIST(values);
+
+    return NewAST(ctx->file, start, pos, Assign, .targets=targets, .values=values);
+}
+
+PARSER(parse_statement) {
+    ast_t *stmt = NULL;
+    if ((stmt=parse_declaration(ctx, pos))
+        || (stmt=parse_doctest(ctx, pos))
+        || (stmt=parse_say(ctx, pos)))
+        return stmt;
+
+    if (!(false 
+        || (stmt=parse_update(ctx, pos))
+        || (stmt=parse_assignment(ctx, pos))
+    ))
+        stmt = parse_extended_expr(ctx, pos);
+    
+    for (bool progress = (stmt != NULL); progress; ) {
+        ast_t *new_stmt;
+        progress = false;
+        if (stmt->tag == Var) {
+            progress = (false
+                || (new_stmt=parse_method_call_suffix(ctx, stmt))
+                || (new_stmt=parse_fncall_suffix(ctx, stmt))
+            );
+        } else if (stmt->tag == FunctionCall) {
+            new_stmt = parse_optional_conditional_suffix(ctx, stmt);
+            progress = (new_stmt != stmt);
+        }
+
+        if (progress) stmt = new_stmt;
+    }
+    return stmt;
+
+}
+
+PARSER(parse_extended_expr) {
+    ast_t *expr = NULL;
+
+    if (false
+        || (expr=optional(ctx, &pos, parse_for))
+        || (expr=optional(ctx, &pos, parse_while))
+        || (expr=optional(ctx, &pos, parse_if))
+        || (expr=optional(ctx, &pos, parse_when))
+        || (expr=optional(ctx, &pos, parse_repeat))
+        || (expr=optional(ctx, &pos, parse_do))
+        || (expr=optional(ctx, &pos, parse_holding))
+        )
+        return expr;
+
+    return parse_expr(ctx, pos);
+}
+
+PARSER(parse_block) {
+    const char *start = pos;
+    spaces(&pos);
+    if (!match(&pos, ":")) return NULL;
+
+    ast_list_t *statements = NULL;
+    if (!indent(ctx, &pos)) {
+        // Inline block
+        spaces(&pos);
+        while (*pos) {
+            spaces(&pos);
+            ast_t *stmt = optional(ctx, &pos, parse_statement);
+            if (!stmt) break;
+            statements = new(ast_list_t, .ast=stmt, .next=statements);
+            spaces(&pos);
+            if (!match(&pos, ";")) break;
+        }
+    } else {
+        goto indented;
+    }
+
+    if (indent(ctx, &pos)) {
+      indented:;
+        int64_t block_indent = get_indent(ctx, pos);
+        whitespace(&pos);
+        while (*pos) {
+            ast_t *stmt = optional(ctx, &pos, parse_statement);
+            if (!stmt) {
+                const char *line_start = pos;
+                if (match_word(&pos, "struct"))
+                    parser_err(ctx, line_start, strchrnul(pos, '\n'), "Struct definitions are only allowed at the top level");
+                else if (match_word(&pos, "enum"))
+                    parser_err(ctx, line_start, strchrnul(pos, '\n'), "Enum definitions are only allowed at the top level");
+                else if (match_word(&pos, "func"))
+                    parser_err(ctx, line_start, strchrnul(pos, '\n'), "Function definitions are only allowed at the top level");
+                else if (match_word(&pos, "use"))
+                    parser_err(ctx, line_start, strchrnul(pos, '\n'), "'use' statements are only allowed at the top level");
+
+                spaces(&pos);
+                if (*pos && *pos != '\r' && *pos != '\n')
+                    parser_err(ctx, pos, strchrnul(pos, '\n'), "I couldn't parse this line");
+                break;
+            }
+            statements = new(ast_list_t, .ast=stmt, .next=statements);
+            whitespace(&pos);
+
+            // Guard against having two valid statements on the same line, separated by spaces (but no newlines):
+            if (!memchr(stmt->end, '\n', (size_t)(pos - stmt->end))) {
+                if (*pos)
+                    parser_err(ctx, pos, strchrnul(pos, '\n'), "I don't know how to parse the rest of this line");
+                pos = stmt->end;
+                break;
+            }
+
+            if (get_indent(ctx, pos) != block_indent) {
+                pos = stmt->end; // backtrack
+                break;
+            }
+        }
+    }
+    REVERSE_LIST(statements);
+    return NewAST(ctx->file, start, pos, Block, .statements=statements);
+}
+
+PARSER(parse_namespace) {
+    const char *start = pos;
+    whitespace(&pos);
+    int64_t indent = get_indent(ctx, pos);
+    ast_list_t *statements = NULL;
+    for (;;) {
+        const char *next = pos;
+        whitespace(&next);
+        if (get_indent(ctx, next) != indent) break;
+        ast_t *stmt;
+        if ((stmt=optional(ctx, &pos, parse_struct_def))
+            ||(stmt=optional(ctx, &pos, parse_enum_def))
+            ||(stmt=optional(ctx, &pos, parse_lang_def))
+            ||(stmt=optional(ctx, &pos, parse_func_def))
+            ||(stmt=optional(ctx, &pos, parse_convert_def))
+            ||(stmt=optional(ctx, &pos, parse_use))
+            ||(stmt=optional(ctx, &pos, parse_extern))
+            ||(stmt=optional(ctx, &pos, parse_inline_c))
+            ||(stmt=optional(ctx, &pos, parse_declaration)))
+        {
+            statements = new(ast_list_t, .ast=stmt, .next=statements);
+            pos = stmt->end;
+            whitespace(&pos); // TODO: check for newline
+            // if (!(space_types & WHITESPACE_NEWLINES)) {
+            //     pos = stmt->end;
+            //     break;
+            // }
+        } else {
+            if (get_indent(ctx, next) > indent && next < strchrnul(next, '\n'))
+                parser_err(ctx, next, strchrnul(next, '\n'), "I couldn't parse this namespace declaration");
+            break;
+        }
+    }
+    REVERSE_LIST(statements);
+    return NewAST(ctx->file, start, pos, Block, .statements=statements);
+}
+
+PARSER(parse_file_body) {
+    const char *start = pos;
+    whitespace(&pos);
+    ast_list_t *statements = NULL;
+    for (;;) {
+        const char *next = pos;
+        whitespace(&next);
+        if (get_indent(ctx, next) != 0) break;
+        ast_t *stmt;
+        if ((stmt=optional(ctx, &pos, parse_struct_def))
+            ||(stmt=optional(ctx, &pos, parse_enum_def))
+            ||(stmt=optional(ctx, &pos, parse_lang_def))
+            ||(stmt=optional(ctx, &pos, parse_func_def))
+            ||(stmt=optional(ctx, &pos, parse_convert_def))
+            ||(stmt=optional(ctx, &pos, parse_use))
+            ||(stmt=optional(ctx, &pos, parse_extern))
+            ||(stmt=optional(ctx, &pos, parse_inline_c))
+            ||(stmt=optional(ctx, &pos, parse_declaration)))
+        {
+            statements = new(ast_list_t, .ast=stmt, .next=statements);
+            pos = stmt->end;
+            whitespace(&pos); // TODO: check for newline
+        } else {
+            break;
+        }
+    }
+    whitespace(&pos);
+    if (pos < ctx->file->text + ctx->file->len && *pos != '\0') {
+        parser_err(ctx, pos, strchrnul(pos, '\n'), "I expect all top-level statements to be declarations of some kind");
+    }
+    REVERSE_LIST(statements);
+    return NewAST(ctx->file, start, pos, Block, .statements=statements);
+}
+
+PARSER(parse_struct_def) {
+    // struct Foo(...) [: \n body]
+    const char *start = pos;
+    if (!match_word(&pos, "struct")) return NULL;
+
+    int64_t starting_indent = get_indent(ctx, pos);
+
+    spaces(&pos);
+    const char *name = get_id(&pos);
+    if (!name) parser_err(ctx, start, pos, "I expected a name for this struct");
+    spaces(&pos);
+
+    if (!match(&pos, "("))
+        parser_err(ctx, pos, pos, "I expected a '(' and a list of fields here");
+
+    arg_ast_t *fields = parse_args(ctx, &pos);
+
+    whitespace(&pos);
+    bool secret = false, external = false, opaque = false;
+    if (match(&pos, ";")) { // Extra flags
+        whitespace(&pos);
+        for (;;) {
+            if (match_word(&pos, "secret")) {
+                secret = true;
+            } else if (match_word(&pos, "extern")) {
+                external = true;
+            } else if (match_word(&pos, "opaque")) {
+                if (fields)
+                    parser_err(ctx, pos-strlen("opaque"), pos, "A struct can't be opaque if it has fields defined");
+                opaque = true;
+            } else {
+                break;
+            }
+
+            if (!match_separator(&pos))
+                break;
+        }
+    }
+
+
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this struct");
+
+    ast_t *namespace = NULL;
+    if (match(&pos, ":")) {
+        const char *ns_pos = pos;
+        whitespace(&ns_pos);
+        int64_t ns_indent = get_indent(ctx, ns_pos);
+        if (ns_indent > starting_indent) {
+            pos = ns_pos;
+            namespace = optional(ctx, &pos, parse_namespace);
+        }
+    }
+    if (!namespace)
+        namespace = NewAST(ctx->file, pos, pos, Block, .statements=NULL);
+    return NewAST(ctx->file, start, pos, StructDef, .name=name, .fields=fields, .namespace=namespace,
+                  .secret=secret, .external=external, .opaque=opaque);
+}
+
+PARSER(parse_enum_def) {
+    // tagged union: enum Foo(a, b(x:Int,y:Int)=5, ...) [: \n namespace]
+    const char *start = pos;
+    if (!match_word(&pos, "enum")) return NULL;
+    int64_t starting_indent = get_indent(ctx, pos);
+    spaces(&pos);
+    const char *name = get_id(&pos);
+    if (!name)
+        parser_err(ctx, start, pos, "I expected a name for this enum");
+    spaces(&pos);
+    if (!match(&pos, "(")) return NULL;
+
+    tag_ast_t *tags = NULL;
+    whitespace(&pos);
+    for (;;) {
+        spaces(&pos);
+        const char *tag_name = get_id(&pos);
+        if (!tag_name) break;
+
+        spaces(&pos);
+        arg_ast_t *fields;
+        bool secret = false;
+        if (match(&pos, "(")) {
+            whitespace(&pos);
+            fields = parse_args(ctx, &pos);
+            whitespace(&pos);
+            if (match(&pos, ";")) { // Extra flags
+                whitespace(&pos);
+                secret = match_word(&pos, "secret");
+                whitespace(&pos);
+            }
+            expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this tagged union member");
+        } else {
+            fields = NULL;
+        }
+
+        tags = new(tag_ast_t, .name=tag_name, .fields=fields, .secret=secret, .next=tags);
+
+        if (!match_separator(&pos))
+            break;
+    }
+
+    whitespace(&pos);
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this enum definition");
+
+    REVERSE_LIST(tags);
+
+    ast_t *namespace = NULL;
+    if (match(&pos, ":")) {
+        const char *ns_pos = pos;
+        whitespace(&ns_pos);
+        int64_t ns_indent = get_indent(ctx, ns_pos);
+        if (ns_indent > starting_indent) {
+            pos = ns_pos;
+            namespace = optional(ctx, &pos, parse_namespace);
+        }
+    }
+    if (!namespace)
+        namespace = NewAST(ctx->file, pos, pos, Block, .statements=NULL);
+
+    return NewAST(ctx->file, start, pos, EnumDef, .name=name, .tags=tags, .namespace=namespace);
+}
+
+PARSER(parse_lang_def) {
+    const char *start = pos;
+    // lang Name: [namespace...]
+    if (!match_word(&pos, "lang")) return NULL;
+    int64_t starting_indent = get_indent(ctx, pos);
+    spaces(&pos);
+    const char *name = get_id(&pos);
+    if (!name)
+        parser_err(ctx, start, pos, "I expected a name for this lang");
+    spaces(&pos);
+
+    ast_t *namespace = NULL;
+    if (match(&pos, ":")) {
+        const char *ns_pos = pos;
+        whitespace(&ns_pos);
+        int64_t ns_indent = get_indent(ctx, ns_pos);
+        if (ns_indent > starting_indent) {
+            pos = ns_pos;
+            namespace = optional(ctx, &pos, parse_namespace);
+        }
+    }
+    if (!namespace)
+        namespace = NewAST(ctx->file, pos, pos, Block, .statements=NULL);
+
+    return NewAST(ctx->file, start, pos, LangDef, .name=name, .namespace=namespace);
+}
+
+arg_ast_t *parse_args(parse_ctx_t *ctx, const char **pos)
+{
+    arg_ast_t *args = NULL;
+    for (;;) {
+        const char *batch_start = *pos;
+        ast_t *default_val = NULL;
+        type_ast_t *type = NULL;
+
+        typedef struct name_list_s {
+            const char *name;
+            struct name_list_s *next;
+        } name_list_t;
+
+        name_list_t *names = NULL;
+        for (;;) {
+            whitespace(pos);
+            const char *name = get_id(pos);
+            if (!name) break;
+            whitespace(pos);
+            if (strncmp(*pos, "==", 2) != 0 && match(pos, "=")) {
+                default_val = expect(ctx, *pos-1, pos, parse_term, "I expected a value after this '='");
+                names = new(name_list_t, .name=name, .next=names);
+                break;
+            } else if (match(pos, ":")) {
+                type = expect(ctx, *pos-1, pos, parse_type, "I expected a type here");
+                names = new(name_list_t, .name=name, .next=names);
+                break;
+            } else if (name) {
+                names = new(name_list_t, .name=name, .next=names);
+                spaces(pos);
+                if (!match(pos, ",")) break;
+            } else {
+                break;
+            }
+        }
+        if (!names) break;
+        if (!default_val && !type)
+            parser_err(ctx, batch_start, *pos, "I expected a ':' and type, or '=' and a default value after this parameter (%s)",
+                       names->name);
+
+        REVERSE_LIST(names);
+        for (; names; names = names->next)
+            args = new(arg_ast_t, .name=names->name, .type=type, .value=default_val, .next=args);
+
+        if (!match_separator(pos))
+            break;
+    }
+
+    REVERSE_LIST(args);
+    return args;
+}
+
+PARSER(parse_func_def) {
+    const char *start = pos;
+    if (!match_word(&pos, "func")) return NULL;
+
+    ast_t *name = optional(ctx, &pos, parse_var);
+    if (!name) return NULL;
+
+    spaces(&pos);
+
+    if (!match(&pos, "(")) return NULL;
+
+    arg_ast_t *args = parse_args(ctx, &pos);
+    spaces(&pos);
+    type_ast_t *ret_type = match(&pos, "->") ? optional(ctx, &pos, parse_type) : NULL;
+    whitespace(&pos);
+    bool is_inline = false;
+    ast_t *cache_ast = NULL;
+    for (bool specials = match(&pos, ";"); specials; specials = match_separator(&pos)) {
+        const char *flag_start = pos;
+        if (match_word(&pos, "inline")) {
+            is_inline = true;
+        } else if (match_word(&pos, "cached")) {
+            if (!cache_ast) cache_ast = NewAST(ctx->file, pos, pos, Int, .str="-1");
+        } else if (match_word(&pos, "cache_size")) {
+            whitespace(&pos);
+            if (!match(&pos, "="))
+                parser_err(ctx, flag_start, pos, "I expected a value for 'cache_size'");
+            whitespace(&pos);
+            cache_ast = expect(ctx, start, &pos, parse_expr, "I expected a maximum size for the cache");
+        }
+    }
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this function definition");
+
+    ast_t *body = expect(ctx, start, &pos, parse_block,
+                             "This function needs a body block");
+    return NewAST(ctx->file, start, pos, FunctionDef,
+                  .name=name, .args=args, .ret_type=ret_type, .body=body, .cache=cache_ast,
+                  .is_inline=is_inline);
+}
+
+PARSER(parse_convert_def) {
+    const char *start = pos;
+    if (!match_word(&pos, "convert")) return NULL;
+
+    spaces(&pos);
+
+    if (!match(&pos, "(")) return NULL;
+
+    arg_ast_t *args = parse_args(ctx, &pos);
+    spaces(&pos);
+    type_ast_t *ret_type = match(&pos, "->") ? optional(ctx, &pos, parse_type) : NULL;
+    whitespace(&pos);
+    bool is_inline = false;
+    ast_t *cache_ast = NULL;
+    for (bool specials = match(&pos, ";"); specials; specials = match_separator(&pos)) {
+        const char *flag_start = pos;
+        if (match_word(&pos, "inline")) {
+            is_inline = true;
+        } else if (match_word(&pos, "cached")) {
+            if (!cache_ast) cache_ast = NewAST(ctx->file, pos, pos, Int, .str="-1");
+        } else if (match_word(&pos, "cache_size")) {
+            whitespace(&pos);
+            if (!match(&pos, "="))
+                parser_err(ctx, flag_start, pos, "I expected a value for 'cache_size'");
+            whitespace(&pos);
+            cache_ast = expect(ctx, start, &pos, parse_expr, "I expected a maximum size for the cache");
+        }
+    }
+    expect_closing(ctx, &pos, ")", "I wasn't able to parse the rest of this function definition");
+
+    ast_t *body = expect(ctx, start, &pos, parse_block,
+                             "This function needs a body block");
+    return NewAST(ctx->file, start, pos, ConvertDef,
+                  .args=args, .ret_type=ret_type, .body=body, .cache=cache_ast, .is_inline=is_inline);
+}
+
+PARSER(parse_extern) {
+    const char *start = pos;
+    if (!match_word(&pos, "extern")) return NULL;
+    spaces(&pos);
+    const char* name = get_id(&pos);
+    spaces(&pos);
+    if (!match(&pos, ":"))
+        parser_err(ctx, start, pos, "I couldn't get a type for this extern");
+    type_ast_t *type = expect(ctx, start, &pos, parse_type, "I couldn't parse the type for this extern");
+    return NewAST(ctx->file, start, pos, Extern, .name=name, .type=type);
+}
+
+PARSER(parse_inline_c) {
+    const char *start = pos;
+    if (!match_word(&pos, "inline")) return NULL;
+
+    spaces(&pos);
+    if (!match_word(&pos, "C")) return NULL;
+
+    spaces(&pos);
+    type_ast_t *type = NULL;
+    if (match(&pos, ":"))
+        type = expect(ctx, start, &pos, parse_type, "I couldn't parse the type for this inline C code");
+
+    spaces(&pos);
+    if (!match(&pos, "{"))
+        parser_err(ctx, start, pos, "I expected a '{' here");
+
+    int depth = 1;
+    const char *c_code_start = pos;
+    for (; *pos && depth > 0; ++pos) {
+        if (*pos == '}') --depth;
+        else if (*pos == '{') ++depth;
+    }
+
+    if (depth != 0)
+        parser_err(ctx, start, start+1, "I couldn't find the closing '}' for this inline C code");
+
+    CORD c_code = GC_strndup(c_code_start, (size_t)((pos-1) - c_code_start));
+    return NewAST(ctx->file, start, pos, InlineCCode, .code=c_code, .type_ast=type);
+}
+
+PARSER(parse_doctest) {
+    const char *start = pos;
+    if (!match(&pos, ">>")) return NULL;
+    spaces(&pos);
+    ast_t *expr = expect(ctx, start, &pos, parse_statement, "I couldn't parse the expression for this doctest");
+    whitespace(&pos);
+    const char* output = NULL;
+    if (match(&pos, "=")) {
+        spaces(&pos);
+        const char *output_start = pos,
+                   *output_end = pos + strcspn(pos, "\r\n");
+        if (output_end <= output_start)
+            parser_err(ctx, output_start, output_end, "You're missing expected output here");
+        int64_t trailing_spaces = 0;
+        while (output_end - trailing_spaces - 1 > output_start && (output_end[-trailing_spaces-1] == ' ' || output_end[-trailing_spaces-1] == '\t'))
+            ++trailing_spaces;
+        output = GC_strndup(output_start, (size_t)((output_end - output_start) - trailing_spaces));
+        pos = output_end;
+    } else {
+        pos = expr->end;
+    }
+    return NewAST(ctx->file, start, pos, DocTest, .expr=expr, .output=output);
+}
+
+PARSER(parse_say) {
+    const char *start = pos;
+    if (!match(&pos, "!!")) return NULL;
+    spaces(&pos);
+
+    ast_list_t *chunks = NULL;
+    CORD chunk = CORD_EMPTY;
+    const char *chunk_start = pos;
+    const char open_interp = '$';
+    while (pos < ctx->file->text + ctx->file->len) {
+        if (*pos == open_interp) { // Interpolation
+            const char *interp_start = pos;
+            if (chunk) {
+                ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .cord=chunk);
+                chunks = new(ast_list_t, .ast=literal, .next=chunks);
+                chunk = NULL;
+            }
+            ++pos;
+            ast_t *interp;
+            if (*pos == ' ' || *pos == '\t')
+                parser_err(ctx, pos, pos+1, "Whitespace is not allowed before an interpolation here");
+            interp = expect(ctx, interp_start, &pos, parse_term, "I expected an interpolation term here");
+            chunks = new(ast_list_t, .ast=interp, .next=chunks);
+            chunk_start = pos;
+        } else if (*pos == '\r' || *pos == '\n') { // Newline
+            break;
+        } else { // Plain character
+            chunk = CORD_cat_char(chunk, *pos);
+            ++pos;
+        }
+    }
+
+    if (chunk) {
+        ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .cord=chunk);
+        chunks = new(ast_list_t, .ast=literal, .next=chunks);
+        chunk = NULL;
+    }
+
+    REVERSE_LIST(chunks);
+    return NewAST(ctx->file, start, pos, PrintStatement, .to_print=chunks);
+}
+
+PARSER(parse_use) {
+    const char *start = pos;
+
+    ast_t *var = parse_var(ctx, pos);
+    if (var) {
+        pos = var->end;
+        spaces(&pos);
+        if (!match(&pos, ":=")) return NULL;
+        spaces(&pos);
+    }
+
+    if (!match_word(&pos, "use")) return NULL;
+    spaces(&pos);
+    size_t name_len = strcspn(pos, " \t\r\n;");
+    if (name_len < 1)
+        parser_err(ctx, start, pos, "There is no module name here to use");
+    char *name = GC_strndup(pos, name_len);
+    pos += name_len;
+    while (match(&pos, ";")) continue;
+    int what; 
+    if (name[0] == '<' || ends_with(name, ".h")) {
+        what = USE_HEADER;
+    } else if (ends_with(name, ".c")) {
+        what = USE_C_CODE;
+    } else if (ends_with(name, ".S") || ends_with(name, ".s")) {
+        what = USE_ASM;
+    } else if (starts_with(name, "./") || starts_with(name, "/") || starts_with(name, "../") || starts_with(name, "~/")) {
+        what = USE_LOCAL;
+    } else if (ends_with(name, ".so")) {
+        what = USE_SHARED_OBJECT;
+    } else {
+        what = USE_MODULE;
+
+        // When `use`ing a URL, convert it to a hash:
+        Text_t text = Text$from_str(name);
+        Array_t m = Text$matches(text, Pattern("{url}"));
+        if (m.length >= 0) {
+            text = Text$trim(text, Pattern("http{0-1 s}://"), true, false);
+            FILE *shasum = popen(heap_strf("echo -n '%s' | sha256sum", Text$as_c_string(text)), "r");
+            const size_t HASH_LEN = 32;
+            char *hash = GC_MALLOC_ATOMIC(HASH_LEN + 1);
+            size_t just_read = fread(hash, sizeof(char), HASH_LEN, shasum);
+            if (just_read < HASH_LEN)
+                errx(1, "Failed to get SHA sum for 'use': %s", name);
+            name = hash;
+        }
+    }
+    return NewAST(ctx->file, start, pos, Use, .var=var, .path=name, .what=what);
+}
+
+ast_t *parse_file(const char *path, jmp_buf *on_err) {
+    if (path[0] != '<') {
+        const char *resolved = resolve_path(path, ".", ".");
+        if (!resolved)
+            errx(1, "Could not resolve path: %s", path);
+        path = resolved;
+    }
+    // NOTE: this cache leaks a bounded amount of memory. The cache will never
+    // hold more than PARSE_CACHE_SIZE entries (see below), but each entry's
+    // AST holds onto a reference to the file it came from, so they could
+    // potentially be somewhat large.
+    static Table_t cached = {};
+    ast_t *ast = Table$str_get(cached, path);
+    if (ast) return ast;
+
+    file_t *file;
+    if (path[0] == '<') {
+        const char *endbracket = strchr(path, '>');
+        if (!endbracket) return NULL;
+        file = spoof_file(GC_strndup(path, (size_t)(endbracket + 1 - path)), endbracket + 1);
+    } else {
+        file = load_file(path);
+        if (!file) return NULL;
+    }
+
+    parse_ctx_t ctx = {
+        .file=file,
+        .on_err=on_err,
+    };
+
+    const char *pos = file->text;
+    if (match(&pos, "#!")) // shebang
+        some_not(&pos, "\r\n");
+
+    whitespace(&pos);
+    ast = parse_file_body(&ctx, pos);
+    pos = ast->end;
+    whitespace(&pos);
+    if (pos < file->text + file->len && *pos != '\0') {
+        parser_err(&ctx, pos, pos + strlen(pos), "I couldn't parse this part of the file");
+    }
+
+    // If cache is getting too big, evict a random entry:
+    if (cached.entries.length > PARSE_CACHE_SIZE) {
+        uint32_t i = arc4random_uniform(cached.entries.length);
+        struct {const char *path; ast_t *ast; } *to_remove = Table$entry(cached, i+1);
+        Table$str_remove(&cached, to_remove->path);
+    }
+
+    // Save the AST in the cache:
+    Table$str_set(&cached, path, ast);
+    return ast;
+}
+
+type_ast_t *parse_type_str(const char *str) {
+    file_t *file = spoof_file("<type>", str);
+    parse_ctx_t ctx = {
+        .file=file,
+        .on_err=NULL,
+    };
+
+    const char *pos = file->text;
+    whitespace(&pos);
+    type_ast_t *ast = parse_type(&ctx, pos);
+    if (!ast) return ast;
+    pos = ast->end;
+    whitespace(&pos);
+    if (strlen(pos) > 0) {
+        parser_err(&ctx, pos, pos + strlen(pos), "I couldn't parse this part of the type");
+    }
+    return ast;
+}
+
+ast_t *parse(const char *str) {
+    file_t *file = spoof_file("<string>", str);
+    parse_ctx_t ctx = {
+        .file=file,
+        .on_err=NULL,
+    };
+
+    const char *pos = file->text;
+    whitespace(&pos);
+    ast_t *ast = parse_file_body(&ctx, pos);
+    pos = ast->end;
+    whitespace(&pos);
+    if (pos < file->text + file->len && *pos != '\0')
+        parser_err(&ctx, pos, pos + strlen(pos), "I couldn't parse this part of the file");
+    return ast;
+}
+
+// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0