Split out text parsing logic

1 files changed, 185 insertions, 0 deletions

diff --git a/src/parse/text.c b/src/parse/text.c
new file mode 100644
index 00000000..b9827644
--- /dev/null
+++ b/src/parse/text.c
@@ -0,0 +1,185 @@
+// Logic for parsing text literals
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "../unistr-fixed.h"
+#include <unictype.h>
+#include <uniname.h>
+
+#include "../ast.h"
+#include "../stdlib/text.h"
+#include "../stdlib/util.h"
+#include "context.h"
+#include "errors.h"
+#include "parse.h"
+#include "types.h"
+#include "utils.h"
+
+static const char closing[128] = {['('] = ')', ['['] = ']', ['<'] = '>', ['{'] = '}'};
+
+static ast_list_t *_parse_text_helper(parse_ctx_t *ctx, const char **out_pos, char open_quote, char close_quote,
+                                      char open_interp, bool allow_escapes) {
+    const char *pos = *out_pos;
+    int64_t starting_indent = get_indent(ctx, pos);
+    int64_t string_indent = starting_indent + SPACES_PER_INDENT;
+    ast_list_t *chunks = NULL;
+    Text_t chunk = EMPTY_TEXT;
+    const char *chunk_start = pos;
+    int depth = 1;
+    bool leading_newline = false;
+    int64_t plain_span_len = 0;
+#define FLUSH_PLAIN_SPAN()                                                                                             \
+    do {                                                                                                               \
+        if (plain_span_len > 0) {                                                                                      \
+            chunk = Texts(chunk, Text$from_strn(pos - plain_span_len, (size_t)plain_span_len));                        \
+            plain_span_len = 0;                                                                                        \
+        }                                                                                                              \
+    } while (0)
+    for (const char *end = ctx->file->text + ctx->file->len; pos < end && depth > 0;) {
+        const char *after_indentation = pos;
+        if (*pos == open_interp) { // Interpolation
+            FLUSH_PLAIN_SPAN();
+            const char *interp_start = pos;
+            if (chunk.length > 0) {
+                ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .text = chunk);
+                chunks = new (ast_list_t, .ast = literal, .next = chunks);
+                chunk = EMPTY_TEXT;
+            }
+            ++pos;
+            ast_t *interp;
+            if (*pos == ' ' || *pos == '\t')
+                parser_err(ctx, pos, pos + 1, "Whitespace is not allowed before an interpolation here");
+            interp = expect(ctx, interp_start, &pos, parse_term_no_suffix, "I expected an interpolation term here");
+            chunks = new (ast_list_t, .ast = interp, .next = chunks);
+            chunk_start = pos;
+        } else if (allow_escapes && *pos == '\\') {
+            FLUSH_PLAIN_SPAN();
+            const char *c = unescape(ctx, &pos);
+            chunk = Texts(chunk, Text$from_str(c));
+        } else if (!leading_newline && *pos == open_quote && closing[(int)open_quote]) { // Nested pair begin
+            if (get_indent(ctx, pos) == starting_indent) {
+                ++depth;
+            }
+            plain_span_len += 1;
+            ++pos;
+        } else if (!leading_newline && *pos == close_quote) { // Nested pair end
+            if (get_indent(ctx, pos) == starting_indent) {
+                --depth;
+                if (depth == 0) break;
+            }
+            plain_span_len += 1;
+            ++pos;
+        } else if (newline_with_indentation(&after_indentation, string_indent)) { // Newline
+            FLUSH_PLAIN_SPAN();
+            pos = after_indentation;
+            if (!leading_newline && !(chunk.length > 0 || chunks)) {
+                leading_newline = true;
+            } else {
+                chunk = Texts(chunk, Text("\n"));
+            }
+        } else if (newline_with_indentation(&after_indentation, starting_indent)) { // Line continuation (..)
+            FLUSH_PLAIN_SPAN();
+            pos = after_indentation;
+            if (*pos == close_quote) {
+                break;
+            } else if (some_of(&pos, ".") >= 2) {
+                // Multi-line split
+                continue;
+            } else {
+                parser_err(ctx, pos, eol(pos),
+                           "This multi-line string should be either indented or have '..' at the front");
+            }
+        } else { // Plain character
+            ucs4_t codepoint;
+            const char *next = (const char *)u8_next(&codepoint, (const uint8_t *)pos);
+            plain_span_len += (int64_t)(next - pos);
+            if (next == NULL) break;
+            pos = next;
+        }
+    }
+
+    FLUSH_PLAIN_SPAN();
+#undef FLUSH_PLAIN_SPAN
+
+    if (chunk.length > 0) {
+        ast_t *literal = NewAST(ctx->file, chunk_start, pos, TextLiteral, .text = chunk);
+        chunks = new (ast_list_t, .ast = literal, .next = chunks);
+        chunk = EMPTY_TEXT;
+    }
+
+    REVERSE_LIST(chunks);
+    char close_str[2] = {close_quote, 0};
+    expect_closing(ctx, &pos, close_str, "I was expecting a ", close_quote, " to finish this string");
+    *out_pos = pos;
+    return chunks;
+}
+
+public
+ast_t *parse_text(parse_ctx_t *ctx, const char *pos) {
+    // ('"' ... '"' / "'" ... "'" / "`" ... "`")
+    // "$" [name] [interp-char] quote-char ... close-quote
+    const char *start = pos;
+    const char *lang = NULL;
+
+    char open_quote, close_quote, open_interp = '$';
+    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 = '$';
+    } else if (match(&pos, "$")) { // 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;
+        }
+        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;
+    } else {
+        return NULL;
+    }
+
+    bool allow_escapes = (open_quote != '`');
+    ast_list_t *chunks = _parse_text_helper(ctx, &pos, open_quote, close_quote, open_interp, allow_escapes);
+    bool colorize = match(&pos, "~") && match_word(&pos, "colorized");
+    return NewAST(ctx->file, start, pos, TextJoin, .lang = lang, .children = chunks, .colorize = colorize);
+}
+
+public
+ast_t *parse_inline_c(parse_ctx_t *ctx, const char *pos) {
+    const char *start = pos;
+    if (!match_word(&pos, "C_code")) return NULL;
+
+    spaces(&pos);
+    type_ast_t *type = NULL;
+    ast_list_t *chunks;
+    if (match(&pos, ":")) {
+        type = expect(ctx, start, &pos, parse_type, "I couldn't parse the type for this C_code code");
+        spaces(&pos);
+        if (!match(&pos, "(")) parser_err(ctx, start, pos, "I expected a '(' here");
+        chunks = new (ast_list_t, .ast = NewAST(ctx->file, pos, pos, TextLiteral, Text("({")),
+                      .next = _parse_text_helper(ctx, &pos, '(', ')', '@', false));
+        if (type) {
+            REVERSE_LIST(chunks);
+            chunks = new (ast_list_t, .ast = NewAST(ctx->file, pos, pos, TextLiteral, Text("; })")), .next = chunks);
+            REVERSE_LIST(chunks);
+        }
+    } else {
+        if (!match(&pos, "{")) parser_err(ctx, start, pos, "I expected a '{' here");
+        chunks = _parse_text_helper(ctx, &pos, '{', '}', '@', false);
+    }
+
+    return NewAST(ctx->file, start, pos, InlineCCode, .chunks = chunks, .type_ast = type);
+}