From 9e7cb4f19473571d76bf4b7b5ddc772ef8375a4e Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Fri, 18 Dec 2015 06:46:31 -0800
Subject: New --debug-expansion option.

* txr.c (opt_dbg_expansion): New global variable.
(help): Print summary for --debug-expansion.
(txr_main): Recognize new option and set flag.

* parser.y (parse_once): Suppress debug stepping around parser
if opt_dbg_expansion is false.

* txr.1 (opt_dbg_expansion): Declared.

* txr.1: Documented new option.
---
 parser.y | 10 ++++++++++
 txr.1    |  8 +++++++-
 txr.c    | 11 +++++++++++
 txr.h    |  1 +
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/parser.y b/parser.y
index b22a7280..7fb42fec 100644
--- a/parser.y
+++ b/parser.y
@@ -52,6 +52,8 @@
 #include "gc.h"
 #include "args.h"
 #include "cadr.h"
+#include "debug.h"
+#include "txr.h"
 #include "parser.h"
 
 static val sym_helper(parser_t *parser, wchar_t *lexeme, val meta_allowed);
@@ -1556,12 +1558,17 @@ void yybadtoken(parser_t *parser, int tok, val context)
 int parse_once(val stream, val name, parser_t *parser)
 {
   int res = 0;
+#if CONFIG_DEBUG_SUPPORT
+  debug_state_t ds = debug_set_state(opt_dbg_expansion ? 0 : -1,
+                                     opt_dbg_expansion);
+#endif
 
   parser_common_init(parser);
 
   parser->stream = stream;
   parser->name = name;
 
+
   uw_catch_begin(cons(error_s, nil), esym, eobj);
 
   res = yyparse(parser->scanner, parser);
@@ -1573,6 +1580,9 @@ int parse_once(val stream, val name, parser_t *parser)
 
   uw_unwind {
     parser_cleanup(parser);
+#if CONFIG_DEBUG_SUPPORT
+    debug_restore_state(ds);
+#endif
   }
 
   uw_catch_end;
diff --git a/txr.1 b/txr.1
index 0fd199c8..1c8f20c3 100644
--- a/txr.1
+++ b/txr.1
@@ -687,10 +687,16 @@ function for a description.
 .meIP --debug-autoload
 This option turns on debugging, like
 .code --debugger
-but also arranges for stepping into the auto-load processing of
+but also requests stepping into the auto-load processing of
 \*(TL library code.  Normally, debugging through the evaluations
 triggered by auto-loading is suppressed.
 
+.meIP --debug-expansion
+This option turns on debugging, like
+.code --debugger
+but also requests stepping into the parse-time macro-expansion
+of \*(TL code embedded in \*(TX queries. Normally, this is suppressed.
+
 .coIP --help
 Prints usage summary on standard output, and terminates successfully.
 
diff --git a/txr.c b/txr.c
index 991666bb..c1b3a838 100644
--- a/txr.c
+++ b/txr.c
@@ -63,6 +63,7 @@ static const char *progname_u8;
 static val progpath = nil;
 int opt_noninteractive;
 int opt_compat;
+int opt_dbg_expansion;
 val stdlib_path;
 
 /*
@@ -154,6 +155,7 @@ static void help(void)
 "--gc-delta=N           Invoke garbage collection when malloc activity\n"
 "                       increments by N megabytes since last collection.\n"
 "--debug-autoload       Allow debugger to step through library auto-loading.\n"
+"--debug-expansion      Allow debugger to step through macro-expansion of query.\n"
 "--yydebug              Debug Yacc parser, if compiled with YYDEBUG support.\n"
 "--gc-debug             Enable a garbage collector stress test (slow).\n"
 "--vg-debug             Enable Valgrind integration, if compiled in.\n"
@@ -569,6 +571,15 @@ int txr_main(int argc, char **argv)
 #else
         no_dbg_support(opt);
         return EXIT_FAILURE;
+#endif
+      } else if (equal(opt, lit("debug-expansion"))) {
+#if CONFIG_DEBUG_SUPPORT
+        opt_debugger = 1;
+        opt_dbg_expansion = 1;
+        continue;
+#else
+        no_dbg_support(opt);
+        return EXIT_FAILURE;
 #endif
       } else if (equal(opt, lit("yydebug"))) {
         if (have_yydebug) {
diff --git a/txr.h b/txr.h
index 0fe34df4..6d9d82ce 100644
--- a/txr.h
+++ b/txr.h
@@ -37,6 +37,7 @@ extern int opt_noninteractive;
 extern int opt_compat;
 extern int opt_debugger;
 extern int opt_dbg_autoload;
+extern int opt_dbg_expansion;
 extern alloc_bytes_t opt_gc_delta;
 extern const wchli_t *version;
 extern const wchar_t *progname;
-- 
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