From 63032c4bb70d9c86348ac9540fd91b01acc3a4c0 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Sat, 7 Mar 2020 16:23:10 +0100
Subject: [PATCH] cgen: minor fixes

---
 vlib/builtin/string.v  |  2 +-
 vlib/v/ast/ast.v       | 14 ++++++++------
 vlib/v/gen/cgen.v      | 19 +++++++++++++++----
 vlib/v/parser/parser.v |  9 +++++++--
 4 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/vlib/builtin/string.v b/vlib/builtin/string.v
index 4f26446c7f..a784405780 100644
--- a/vlib/builtin/string.v
+++ b/vlib/builtin/string.v
@@ -1208,7 +1208,7 @@ pub fn (s string) reverse() string {
 		str: malloc(s.len)
 	}
 	for i := s.len - 1; i >= 0; i-- {
-		res[s.len - i - 1] = s[i]
+		res.str[s.len - i - 1] = s[i]
 	}
 	return res
 }
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 086ac8a5ad..307d92a6a6 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -490,11 +490,11 @@ mut:
 
 pub struct MapInit {
 pub:
-	pos  	   token.Position
-	keys 	   []Expr
-	vals 	   []Expr
+	pos        token.Position
+	keys       []Expr
+	vals       []Expr
 mut:
-	typ  	   table.Type
+	typ        table.Type
 	key_type   table.Type
 	value_type table.Type
 }
@@ -510,8 +510,10 @@ pub:
 
 pub struct CastExpr {
 pub:
-	typ  table.Type
-	expr Expr
+	typ     table.Type
+	expr    Expr // `buf`
+	arg     Expr // `n` in `string(buf, n)`
+	has_arg bool
 }
 
 pub struct AssertStmt {
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 9fb7da5560..ae3be96b23 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -415,10 +415,21 @@ fn (g mut Gen) expr(node ast.Expr) {
 
 		}
 		ast.CastExpr {
-			styp := g.table.type_to_str(it.typ)
-			g.write('($styp)(')
-			g.expr(it.expr)
-			g.write(')')
+			if it.typ == table.string_type_idx {
+				g.write('tos(')
+				g.expr(it.expr)
+				if it.has_arg {
+					g.write(',')
+					g.expr(it.arg)
+				}
+				g.write(')')
+			}
+			else {
+				styp := g.table.type_to_str(it.typ)
+				g.write('($styp)(')
+				g.expr(it.expr)
+				g.write(')')
+			}
 		}
 		ast.CharLiteral {
 			g.write("'$it.val'")
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index aaecf35fc4..013558ca88 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -530,7 +530,7 @@ pub fn (p mut Parser) name_expr() ast.Expr {
 	// `map[string]int` initialization
 	if p.tok.lit == 'map' && p.peek_tok.kind == .lsbr {
 		map_type := p.parse_map_type()
-		return ast.MapInit {
+		return ast.MapInit{
 			typ: map_type
 		}
 	}
@@ -562,16 +562,21 @@ pub fn (p mut Parser) name_expr() ast.Expr {
 			to_typ := p.parse_type()
 			p.check(.lpar)
 			mut expr := ast.Expr{}
+			mut arg := ast.Expr{}
+			mut has_arg := false
 			expr = p.expr(0)
 			// TODO, string(b, len)
 			if p.tok.kind == .comma && table.type_idx(to_typ) == table.string_type_idx {
 				p.check(.comma)
-				p.expr(0) // len
+				arg = p.expr(0) // len
+				has_arg = true
 			}
 			p.check(.rpar)
 			node = ast.CastExpr{
 				typ: to_typ
 				expr: expr
+				arg: arg
+				has_arg: has_arg
 			}
 			p.expr_mod = ''
 			return node