1 files changed, 137 insertions, 0 deletions
diff --git a/src/parse/binops.c b/src/parse/binops.c
new file mode 100644
index 00000000..f8d0854d
--- /dev/null
+++ b/src/parse/binops.c
@@ -0,0 +1,137 @@
+#include <stdbool.h>
+#include <string.h>
+
+#include "../ast.h"
+#include "../stdlib/print.h"
+#include "../stdlib/util.h"
+#include "containers.h"
+#include "context.h"
+#include "errors.h"
+#include "files.h"
+#include "functions.h"
+#include "numbers.h"
+#include "parse.h"
+#include "text.h"
+#include "types.h"
+#include "utils.h"
+
+int op_tightness[] = {
+    [Power] = 9,
+    [Multiply] = 8,
+    [Divide] = 8,
+    [Mod] = 8,
+    [Mod1] = 8,
+    [Plus] = 7,
+    [Minus] = 7,
+    [Concat] = 6,
+    [LeftShift] = 5,
+    [RightShift] = 5,
+    [UnsignedLeftShift] = 5,
+    [UnsignedRightShift] = 5,
+    [Min] = 4,
+    [Max] = 4,
+    [Equals] = 3,
+    [NotEquals] = 3,
+    [LessThan] = 2,
+    [LessThanOrEquals] = 2,
+    [GreaterThan] = 2,
+    [GreaterThanOrEquals] = 2,
+    [Compare] = 2,
+    [And] = 1,
+    [Or] = 1,
+    [Xor] = 1,
+};
+
+public
+ast_e match_binary_operator(const char **pos) {
+    switch (**pos) {
+    case '+': {
+        *pos += 1;
+        return match(pos, "+") ? Concat : Plus;
+    }
+    case '-': {
+        *pos += 1;
+        if ((*pos)[0] != ' ' && (*pos)[-2] == ' ') // looks like `fn -5`
+            return Unknown;
+        return Minus;
+    }
+    case '*': *pos += 1; return Multiply;
+    case '/': *pos += 1; return Divide;
+    case '^': *pos += 1; return Power;
+    case '<': {
+        *pos += 1;
+        if (match(pos, "=")) return LessThanOrEquals; // "<="
+        else if (match(pos, ">")) return Compare; // "<>"
+        else if (match(pos, "<")) {
+            if (match(pos, "<")) return UnsignedLeftShift; // "<<<"
+            return LeftShift; // "<<"
+        } else return LessThan;
+    }
+    case '>': {
+        *pos += 1;
+        if (match(pos, "=")) return GreaterThanOrEquals; // ">="
+        if (match(pos, ">")) {
+            if (match(pos, ">")) return UnsignedRightShift; // ">>>"
+            return RightShift; // ">>"
+        }
+        return GreaterThan;
+    }
+    default: {
+        if (match(pos, "!=")) return NotEquals;
+        else if (match(pos, "==") && **pos != '=') return Equals;
+        else if (match_word(pos, "and")) return And;
+        else if (match_word(pos, "or")) return Or;
+        else if (match_word(pos, "xor")) return Xor;
+        else if (match_word(pos, "mod1")) return Mod1;
+        else if (match_word(pos, "mod")) return Mod;
+        else if (match_word(pos, "_min_")) return Min;
+        else if (match_word(pos, "_max_")) return Max;
+        else return Unknown;
+    }
+    }
+}
+
+public
+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 (ast_e op; (op = match_binary_operator(&pos)) != Unknown && op_tightness[op] >= min_tightness; spaces(&pos)) {
+        ast_t *key = NULL;
+        if (op == Min || op == 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_method_call_suffix(ctx, key)) || (new_term = parse_field_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 && key->tag == Var) key = NULL;
+            else if (key) pos = key->end;
+        }
+
+        whitespace(&pos);
+        if (get_line_number(ctx->file, pos) != starting_line && get_indent(ctx, pos) < starting_indent)
+            parser_err(ctx, pos, eol(pos), "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 == Min) {
+            return NewAST(ctx->file, lhs->start, rhs->end, Min, .lhs = lhs, .rhs = rhs, .key = key);
+        } else if (op == Max) {
+            return NewAST(ctx->file, lhs->start, rhs->end, Max, .lhs = lhs, .rhs = rhs, .key = key);
+        } else {
+            lhs = new (ast_t, .file = ctx->file, .start = lhs->start, .end = rhs->end, .tag = op,
+                       .__data.Plus.lhs = lhs, .__data.Plus.rhs = rhs);
+        }
+    }
+    return lhs;
+}