[C]: Add `here` keyword that evaluates to a string with it's location

It's not really a keyword like the other ones, but just handled
completely at the lexer level since it already knows the location of the
token, so it injects a string literal instead.

We also use this in the self-hosted compiler now for better error
reporting for where the error happened internally.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/lexer.c b/src/lexer.c
index 0d34eea..7bf426a 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -200,6 +200,15 @@ Token Lexer_next(Lexer *lexer)
 
 
         default: {
+            // Hack to support getting source locations
+            if (Lexer_starts_with(lexer, "here")) {
+                char *loc_string = calloc(sizeof(char), 100);
+                sprintf(loc_string, "%s:%lld:%lld", lexer->filename, lexer->line+1, lexer->col+1);
+                Token token = Token_from_string(loc_string, Lexer_loc(lexer));
+                advance(lexer, 4);
+                return token;
+            }
+
             // Handle keywords explicitly
             #define LEX_KEYWORD(token_type, str) if (Lexer_starts_with(lexer, str)) return Lexer_make_token(lexer, token_type, strlen(str));
             ENUM_KEYWORDS(LEX_KEYWORD)