From 767e69459ca7b4c13fe93875177040ab3eec8b56 Mon Sep 17 00:00:00 2001
From: Vincent Sanders <vince@kyllikki.org>
Date: Mon, 28 Sep 2015 00:06:47 +0100
Subject: Improve the parser error reporting

The parser now reports the correct file and line number for
errors. Additionally the @n location structure in rules now has a
filename member in addition to first_line. These members are useful
for adding location information in generated source.
---
 src/nsgenbind-lexer.l | 55 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 48 insertions(+), 7 deletions(-)

(limited to 'src/nsgenbind-lexer.l')

diff --git a/src/nsgenbind-lexer.l b/src/nsgenbind-lexer.l
index f32a948..af77368 100644
--- a/src/nsgenbind-lexer.l
+++ b/src/nsgenbind-lexer.l
@@ -15,9 +15,10 @@
 #include "nsgenbind-parser.h"
 #include "nsgenbind-ast.h"
 
-#define YY_USER_ACTION yylloc->first_line = yylloc->last_line; \
-    yylloc->first_column = yylloc->last_column + 1; \
-    yylloc->last_column += yyleng;
+#define YY_USER_ACTION                                             \
+        yylloc->first_line = yylloc->last_line = yylineno;         \
+        yylloc->first_column = yylloc->last_column + 1;            \
+        yylloc->last_column += yyleng;
 
 
 /* Ensure compatability with bison 2.6 and later */
@@ -29,6 +30,43 @@
 #define YYLTYPE NSGENBIND_LTYPE
 #endif
 
+static struct YYLTYPE *locations = NULL;
+
+static struct YYLTYPE *push_location(struct YYLTYPE *head,
+                                     struct YYLTYPE *loc,
+                                     const char *filename)
+{
+        struct YYLTYPE *res;
+        res = calloc(1, sizeof(struct YYLTYPE));
+        /* copy current location and line number */
+        *res = *loc;
+        res->start_line = yylineno;
+        res->next = head;
+
+        /* reset current location */
+        loc->first_line = loc->last_line = 1;
+        loc->first_column = loc->last_column = 1;
+        loc->filename = strdup(filename);
+        yylineno = 1;
+
+        return res;
+}
+
+static struct YYLTYPE *pop_location(struct YYLTYPE *head, struct YYLTYPE *loc)
+{
+        struct YYLTYPE *res = NULL;
+
+        if (head != NULL) {
+                res = head->next;
+                *loc = *head;
+                free(head);
+
+                yylineno = loc->start_line;
+        }
+        return res;
+}
+
+
 %}
 
 /* lexer options */
@@ -165,8 +203,10 @@ unsigned                return TOK_UNSIGNED;
                             fprintf(stderr, "Unable to open include %s\n", yytext);
                             exit(3);
                         }
-     			yypush_buffer_state(yy_create_buffer( yyin, YY_BUF_SIZE ));
-     
+
+                        locations = push_location(locations, yylloc, yytext);
+
+                        yypush_buffer_state(yy_create_buffer(yyin, YY_BUF_SIZE));
                         BEGIN(INITIAL);
                     }
 
@@ -178,9 +218,10 @@ unsigned                return TOK_UNSIGNED;
      			yypop_buffer_state();
      
                         if ( !YY_CURRENT_BUFFER ) {
-                            yyterminate();
+                                yyterminate();
                         } else {
-                            BEGIN(incl);
+                                locations = pop_location(locations, yylloc);
+                                BEGIN(incl);
                         }
 
                     }
-- 
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