From b2072de7173659118cab71ddea2fc618b2a5bf60 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 18 Apr 2018 20:10:23 -0400
Subject: [PATCH] Keep track of line number and filename from preprocessor
 output for error messages

---
 src/parser/parser.l | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/parser/parser.l b/src/parser/parser.l
index 73bcaa5..c5ae6a0 100644
--- a/src/parser/parser.l
+++ b/src/parser/parser.l
@@ -6,10 +6,14 @@
 #include "parser.h"
 #include "parser.tab.h"
 #include "String.h"
+#include <stdlib.h>
 
 #define YY_USER_ACTION yylloc->first_column += yyleng;
 
 static String * build_string = NULL;
+static size_t current_line = 1u;
+static String * current_file = NULL;
+void handle_loc(const char * input);
 
 %}
 
@@ -164,13 +168,36 @@ L?\" {
 [a-zA-Z_][a-zA-Z_0-9]*              return TOK_IDENTIFIER;
 
 ^[ ]*#[ ]+[0-9]+[ ]+\".+\".*$ {
+    handle_loc(yytext);
 }
 \n {
     yylloc->first_line++;
     yylloc->first_column = 0;
     yylloc->last_line++;
     yylloc->last_column = 0;
+    current_line++;
 }
 [ \t\v]             /* ignore whitespace */
 
 %%
+
+void handle_loc(const char * input)
+{
+    while ((*input < '0') || (*input > '9'))
+    {
+        input++;
+    }
+    current_line = (size_t)atol(input) - 1u;
+    while (*input != '"')
+    {
+        input++;
+    }
+    input++;
+    const char * fname_start = input;
+    while (*input != '"')
+    {
+        input++;
+    }
+    size_t fname_len = (input - fname_start);
+    current_file = String_new_size(fname_start, fname_len);
+}