Add better numeric lexing

1 files changed, 61 insertions, 17 deletions

diff --git a/src/main.c b/src/main.c
index 61d02a7..9246092 100644
--- a/src/main.c
+++ b/src/main.c
@@ -239,8 +239,8 @@ scan_skip_whitespace(Scanner *scanner) {
             case '\v': {
                 scan_next(scanner);
             } break;
-            // Found a comment! (skip)
             case ';': {
+                // Found a comment! (skip)
                 scan_skip_line(scanner);
             } break;
             default: {
@@ -318,13 +318,13 @@ emit_token_number(Scanner *scanner) {
         scan_next(scanner);
         scan_next(scanner);
         while (scan_has_next(scanner)) {
-            char c = scan_peek(scanner);
+            c = scan_peek(scanner);
             if (c == '0' || c == '1') {
                 scan_next(scanner);
                 continue;
             }
             if (is_valid_split(c)) {
-                break;
+                return emit_token(current, scanner, TOK_NUMBER);
             }
             scan_skip_until_valid(scanner);
             return emit_token_err(
@@ -334,40 +334,84 @@ emit_token_number(Scanner *scanner) {
         scan_next(scanner);
         scan_next(scanner);
         while (scan_has_next(scanner)) {
-            char c = scan_peek(scanner);
+            c = scan_peek(scanner);
             if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
                 (c >= 'A' && c <= 'F')) {
                 scan_next(scanner);
                 continue;
             }
             if (is_valid_split(c)) {
-                break;
+                return emit_token(current, scanner, TOK_NUMBER);
             }
             scan_skip_until_valid(scanner);
             return emit_token_err(&current,
                                   cstr("malformed number: invalid hex number"));
         }
     } else {
-        // TODO: handle fractions, signs and exponents properly.
+        // Integral.
         while (scan_has_next(scanner)) {
-            char c = scan_peek(scanner);
-            switch (c) {
-                case '+':
-                case '-':
-                case 'e':
-                case 'E':
-                case '.':
-                    scan_next(scanner);
-                    continue;
+            c = scan_peek(scanner);
+            if (c == '.') {
+                scan_next(scanner);
+                break;
             }
             if (c >= '0' && c <= '9') {
                 scan_next(scanner);
                 continue;
             }
-            break;
+            if (is_valid_split(c)) {
+                return emit_token(current, scanner, TOK_NUMBER);
+            }
+            scan_skip_until_valid(scanner);
+            return emit_token_err(&current, cstr("malformed number"));
+        }
+        c = scan_peek(scanner);
+        if (!(c >= '0' && c <= '9')) {
+            return emit_token_err(&current,
+                                  cstr("malformed number: no decimal digits"));
+        }
+        // Decimals.
+        while (scan_has_next(scanner)) {
+            c = scan_peek(scanner);
+            if (c == 'e' || c == 'E') {
+                scan_next(scanner);
+                break;
+            }
+            if (c >= '0' && c <= '9') {
+                scan_next(scanner);
+                continue;
+            }
+            if (is_valid_split(c)) {
+                return emit_token(current, scanner, TOK_NUMBER);
+            }
+            scan_skip_until_valid(scanner);
+            return emit_token_err(&current, cstr("malformed number"));
+        }
+        // Exponent.
+        c = scan_peek(scanner);
+        if (c == '+' || c == '-') {
+            scan_next(scanner);
+        }
+        while (scan_has_next(scanner)) {
+            c = scan_peek(scanner);
+            if (c >= '0' && c <= '9') {
+                scan_next(scanner);
+                continue;
+            }
+            if (c == '.') {
+                scan_next(scanner);
+                return emit_token_err(
+                    &current,
+                    cstr("malformed number: decimals not allowed on exponent"));
+            }
+            if (is_valid_split(c)) {
+                return emit_token(current, scanner, TOK_NUMBER);
+            }
+            scan_skip_until_valid(scanner);
+            return emit_token_err(&current, cstr("malformed number"));
         }
     }
-    return emit_token(current, scanner, TOK_NUMBER);
+    return emit_token_err(&current, cstr("malformed number"));
 }
 
 Token