From 6ffed854cc865bcc38f4439278b7cdd34690d804 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 11 Dec 2019 20:43:13 +0300
Subject: [PATCH] cgen.prepend_to_statement()

---
 v.v                   |  6 +++---
 vlib/compiler/cgen.v  | 14 ++++++++++++++
 vlib/compiler/gen_c.v | 23 +++++++++++------------
 3 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/v.v b/v.v
index 1d62e2c4de..f9ddf2192d 100755
--- a/v.v
+++ b/v.v
@@ -24,7 +24,7 @@ fn main() {
 	//    which may be surprising to v users.
 	stuff_after_executable := os.args[1..]
 	commands := stuff_after_executable.filter(!it.starts_with('-'))
-	
+
 	simple_tools := ['up', 'create', 'test', 'test-compiler', 'build-tools', 'build-examples', 'build-vbinaries']
 	for tool in simple_tools {
 		if tool in commands {
@@ -32,7 +32,7 @@ fn main() {
 			return
 		}
 	}
-  
+
 	// Print the version and exit.
 	if '-v' in options || '--version' in options || 'version' in commands {
 		version_hash := compiler.vhash()
@@ -44,7 +44,7 @@ fn main() {
 		return
 	}
 	else if 'translate' in commands {
-		println('Translating C to V will be available in V 0.3')
+		println('Translating C to V will be available in V 0.3 (January)')
 		return
 	}
 	else if 'search' in commands || 'install' in commands || 'update' in commands || 'remove' in commands {
diff --git a/vlib/compiler/cgen.v b/vlib/compiler/cgen.v
index 793f6f27b9..3be78539a2 100644
--- a/vlib/compiler/cgen.v
+++ b/vlib/compiler/cgen.v
@@ -77,6 +77,16 @@ fn (g mut CGen) genln(s string) {
 	}
 }
 
+// same as `set_placeholder(0, s)`, but faster
+fn (g mut CGen) prepend_to_statement(s string) {
+	if g.is_tmp {
+		g.tmp_line = s + g.tmp_line
+		return
+	}
+	g.lines << s
+	g.prev_line = g.cur_line
+}
+
 fn (g mut CGen) gen(s string) {
 	if g.nogen || g.pass != .main {
 		return
@@ -160,6 +170,10 @@ fn (g mut CGen) set_placeholder(pos int, val string) {
 	if g.nogen || g.pass != .main {
 		return
 	}
+	//if pos == 0 {
+		//g.prepend_to_statement(val)
+		//return
+	//}
 	// g.lines.set(pos, val)
 	if g.is_tmp {
 		left := g.tmp_line[..pos]
diff --git a/vlib/compiler/gen_c.v b/vlib/compiler/gen_c.v
index ceb3276b3d..fea88d4d1d 100644
--- a/vlib/compiler/gen_c.v
+++ b/vlib/compiler/gen_c.v
@@ -1,3 +1,7 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
 module compiler
 
 import strings
@@ -6,26 +10,18 @@ const (
 	dot_ptr = '->'
 )
 
-/*
-fn (p mut Parser) gen_or_else(pos int) string {
-}
-*/
-
-
 // returns the type of the new variable
 fn (p mut Parser) gen_var_decl(name string, is_static bool) string {
-	// Generate expression to tmp because we need its type first
-	// `[typ] [name] = bool_expression();`
-	pos := p.cgen.add_placeholder()
 	p.is_var_decl = true
 	mut typ := p.bool_expression()
+	//mut typ, expr := p.tmp_expr()
 	p.is_var_decl = false
 	if typ.starts_with('...') { typ = typ[3..] }
 	//p.gen('/*after expr*/')
 	// Option check ? or {
 	or_else := p.tok == .key_orelse
 	if or_else {
-		return p.gen_handle_option_or_else(typ, name, pos)
+		return p.gen_handle_option_or_else(typ, name, 0)
 	}
 	gen_name := p.table.var_cgen_name(name)
 	mut nt_gen := p.table.cgen_name_type_pair(gen_name, typ)
@@ -35,7 +31,7 @@ fn (p mut Parser) gen_var_decl(name string, is_static bool) string {
 	} else if typ.starts_with('[') && typ[ typ.len-1 ] != `*` {
 		// a fixed_array initializer, like `v := [1.1, 2.2]!!`
 		// ... should translate to the following in C `f32 v[2] = {1.1, 2.2};`
-		initializer := p.cgen.cur_line[pos..]
+		initializer := p.cgen.cur_line
 		if initializer.len > 0 {
 			p.cgen.resetln(' = {' + initializer.all_after('{') )
 		} else if initializer.len == 0 {
@@ -46,7 +42,10 @@ fn (p mut Parser) gen_var_decl(name string, is_static bool) string {
 	if is_static {
 		nt_gen = 'static $nt_gen'
 	}
-	p.cgen.set_placeholder(pos, nt_gen)
+	// Now that we know the type, prepend it
+	// `[typ] [name] = bool_expression();`
+	//p.cgen.prepend_to_statement(nt_gen)
+	p.cgen.set_placeholder(0, nt_gen)
 	return typ
 }