diagnostics file loc

1 files changed, 24 insertions, 0 deletions

diff --git a/src/fmt.cff b/src/fmt.cff
index 5635103..90b6423 100644
--- a/src/fmt.cff
+++ b/src/fmt.cff
@@ -1,5 +1,6 @@
 import "cffc.hff";
 import "common.hff";
+import "map.hff";
 import "util.hff";
 
 extern fn vpfmt(proc *fn(u8, *void) void, parg *void, fmt *const u8, ap va_list) void {
@@ -282,10 +283,33 @@ extern fn ssfmt(fmt *const u8, ...) *const u8 {
    ap->end();
 }
 
+fn eprifileline(loc Loc) void {
+   let path = fileid2path(loc.fileid);
+   let fp = fopen(path, "rb");
+   let line_begin = 0;
+   for let i = 0; i < loc.idx; ++i {
+      if fgetc(fp) == '\n' {
+         line_begin = i + 1;
+      }
+   }
+   fseek(fp, line_begin, SEEK_SET);
+   fprintf(stderr, "%4d | ", loc.line);
+   for let c u8 = fgetc(fp); c != EOF and c != '\n'; c = fgetc(fp) {
+      fputc(c, stderr);
+   }
+   fputc('\n', stderr);
+   fclose(fp);
+   for let i = 0; i < loc.col; ++i {
+      fputc(' ', stderr);
+   }
+   fprintf(stderr, "^\n");
+}
+
 extern fn vdiag(P *Parser, loc Loc, kind *const u8, fmt *const u8, ap va_list) void {
    efmt("%s:%i:%i: %s: ", fileid2path(loc.fileid), loc.line, loc.col, kind);
    vefmt(fmt, ap);
    efmt("\n");
+   eprifileline(loc);
 }
 
 extern fn fatal(P *Parser, loc Loc, fmt *const u8, ...) void {