From 90bb48db5dabf990118a7fd262f26ec29a2b6483 Mon Sep 17 00:00:00 2001
From: Emily Hudson <emily33901@gmail.com>
Date: Fri, 26 Jul 2019 15:45:16 +0100
Subject: [PATCH] interactive debugging

---
 compiler/cgen.v    | 24 +++++++++++++++---------
 compiler/main.v    |  4 +++-
 compiler/parser.v  | 11 ++++++++---
 compiler/scanner.v |  2 +-
 4 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/compiler/cgen.v b/compiler/cgen.v
index 90330bf248..689d01843a 100644
--- a/compiler/cgen.v
+++ b/compiler/cgen.v
@@ -24,14 +24,17 @@ struct CGen {
 	//buf          strings.Builder 
 	is_user      bool
 mut:
-	run          Pass
-	nogen        bool
-	tmp_line     string
-	cur_line     string
-	prev_line    string
-	is_tmp       bool
-	fn_main      string
-	stash        string
+	run             Pass
+	nogen           bool
+	tmp_line        string
+	cur_line        string
+	prev_line       string
+	is_tmp          bool
+	fn_main         string
+	stash           string
+	file            string
+	line            int
+	line_directives bool
 }
 
 fn new_cgen(out_name_c string) *CGen {
@@ -44,7 +47,7 @@ fn new_cgen(out_name_c string) *CGen {
 		out_path: path 
 		out: out 
 		//buf: strings.new_builder(10000) 
-		lines: _make(0, 1000, sizeof(string)) 
+		lines: _make(0, 1000, sizeof(string))
 	}
 	return gen
 }
@@ -59,6 +62,9 @@ fn (g mut CGen) genln(s string) {
 	}
 	g.cur_line = '$g.cur_line $s'
 	if g.cur_line != '' {
+		if g.line_directives && g.cur_line.trim_space() != '' {
+			g.lines << '#line $g.line "$g.file"'
+		}
 		g.lines << g.cur_line
 		g.prev_line = g.cur_line
 		g.cur_line = ''
diff --git a/compiler/main.v b/compiler/main.v
index 76e13cd6db..bbc0029ea8 100644
--- a/compiler/main.v
+++ b/compiler/main.v
@@ -90,6 +90,7 @@ mut:
 	is_run         bool
 	show_c_cmd     bool // `v -show_c_cmd` prints the C command to build program.v.c
 	sanitize       bool // use Clang's new "-fsanitize" option
+	is_debuggable  bool
 	is_debug       bool // keep compiled C files
 	no_auto_free   bool // `v -nofree` disable automatic `free()` insertion for better performance in some applications  (e.g. compilers) 
 	cflags        string // Additional options which will be passed to the C compiler.
@@ -1158,7 +1159,8 @@ fn new_v(args[]string) *V {
 		is_play: args.contains('play')
 		is_prod: args.contains('-prod')
 		is_verbose: args.contains('-verbose')
-		is_debug: args.contains('-debug')
+		is_debuggable: args.contains('-g') // -debuggable implys debug
+		is_debug: args.contains('-debug') || args.contains('-g')
 		obfuscate: obfuscate
 		is_prof: args.contains('-prof')
 		is_live: args.contains('-live')
diff --git a/compiler/parser.v b/compiler/parser.v
index 146c28d58a..fb6ddca11d 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -104,6 +104,10 @@ fn (c mut V) new_parser(path string, run Pass) Parser {
 			path.contains('v/vlib')) 
 			 
 	}
+
+	c.cgen.line_directives = c.pref.is_debuggable
+	c.cgen.file = path
+
 	p.next()
 	// p.scanner.debug_tokens()
 	return p
@@ -1243,7 +1247,7 @@ fn (p mut Parser) var_decl() {
 		// User user = *(User*)tmp.data;
 		// p.assigned_var = ''
 		p.cgen.set_placeholder(pos, '$typ $tmp = ')
-		p.gen(';')
+		p.genln(';')
 		typ = typ.replace('Option_', '')
 		p.next()
 		p.check(.lcbr)
@@ -3317,7 +3321,7 @@ fn (p mut Parser) return_st() {
 					p.cgen.resetln('return $ret')
 				}  else { 
 					tmp := p.get_tmp() 
-					p.cgen.resetln('$expr_type $tmp = $ret;') 
+					p.cgen.resetln('$expr_type $tmp = $ret;\n')
 					p.genln(p.cur_fn.defer_text) 
 					p.genln('return $tmp;') 
 				} 
@@ -3525,10 +3529,11 @@ fn (p mut Parser) fgenln(s string) {
 
 fn (p mut Parser) peek() Token {
 	for {
+		p.cgen.line = p.scanner.line_nr + 1
 		tok := p.scanner.peek()
 		if tok != .nl {
 			return tok
-		}
+		} 
 	}
 }
 
diff --git a/compiler/scanner.v b/compiler/scanner.v
index 840610a4c5..0e1670a716 100644
--- a/compiler/scanner.v
+++ b/compiler/scanner.v
@@ -210,7 +210,7 @@ fn (s mut Scanner) skip_whitespace() {
 	for s.pos < s.text.len && s.text[s.pos].is_white() {
 		// Count \r\n as one line 
 		if is_nl(s.text[s.pos]) && !s.expect('\r\n', s.pos-1) {
-				s.line_nr++
+			s.line_nr++
 		}
 		s.pos++
 	}