From d619944cf5a27fa6b54b7cc6c98261039447dc3b Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Thu, 27 Feb 2020 21:00:33 +0100
Subject: [PATCH] vfmt: []xxx; mut args

---
 vlib/v/ast/ast.v       |  2 ++
 vlib/v/fmt/fmt.v       | 35 ++++++++++++++++++++++++-----------
 vlib/v/parser/fn.v     | 14 ++++++++++----
 vlib/v/parser/parser.v | 19 ++++++++++---------
 4 files changed, 46 insertions(+), 24 deletions(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 236fb895b3..870cc175bc 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -153,6 +153,7 @@ mut:
 	name string
 	args []Expr
 	is_c bool
+	muts []bool
 }
 
 pub struct MethodCallExpr {
@@ -162,6 +163,7 @@ pub:
 	expr Expr
 	name string
 	args []Expr
+	muts []bool
 }
 
 pub struct Return {
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 1114a0282c..455cb4e667 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -252,18 +252,25 @@ fn (f &Fmt) type_to_str(t table.Type) string {
 fn (f mut Fmt) expr(node ast.Expr) {
 	match node {
 		ast.ArrayInit {
-			// type_sym := f.table.get_type_symbol(it.typ)
-			f.write('[')
-			for i, expr in it.exprs {
-				if i > 0 && it.exprs.len > 1 {
-					f.wrap_long_line()
-				}
-				f.expr(expr)
-				if i < it.exprs.len - 1 {
-					f.write(', ')
-				}
+			// `x := []string`
+			if it.exprs.len == 0 && it.typ != 0 {
+				f.write(f.table.type_to_str(it.typ))
+			}
+			// `[1,2,3]`
+			else {
+				// type_sym := f.table.get_type_symbol(it.typ)
+				f.write('[')
+				for i, expr in it.exprs {
+					if i > 0 && it.exprs.len > 1 {
+						f.wrap_long_line()
+					}
+					f.expr(expr)
+					if i < it.exprs.len - 1 {
+						f.write(', ')
+					}
+				}
+				f.write(']')
 			}
-			f.write(']')
 		}
 		ast.AssignExpr {
 			f.expr(it.left)
@@ -294,6 +301,9 @@ fn (f mut Fmt) expr(node ast.Expr) {
 		ast.CallExpr {
 			f.write('${it.name}(')
 			for i, expr in it.args {
+				if it.muts[i] {
+					f.write('mut ')
+				}
 				f.expr(expr)
 				if i != it.args.len - 1 {
 					f.write(', ')
@@ -383,6 +393,9 @@ fn (f mut Fmt) expr(node ast.Expr) {
 			f.expr(it.expr)
 			f.write('.' + it.name + '(')
 			for i, arg in it.args {
+				if it.muts[i] {
+					f.write('mut ')
+				}
 				if i > 0 {
 					f.wrap_long_line()
 				}
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index cbc9fa21a3..ebf67a5a18 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -13,12 +13,13 @@ pub fn (p mut Parser) call_expr(is_c bool, mod string) ast.CallExpr {
 	name := p.check_name()
 	fn_name := if mod.len > 0 { '${mod}.$name' } else { name }
 	p.check(.lpar)
-	args := p.call_args()
+	args, muts := p.call_args()
 	node := ast.CallExpr{
 		name: fn_name
 		args: args
+		muts: muts
 		// tok: tok
-		
+
 		pos: tok.position()
 		is_c: is_c
 	}
@@ -29,11 +30,16 @@ pub fn (p mut Parser) call_expr(is_c bool, mod string) ast.CallExpr {
 	return node
 }
 
-pub fn (p mut Parser) call_args() []ast.Expr {
+pub fn (p mut Parser) call_args() ([]ast.Expr, []bool) {
 	mut args := []ast.Expr
+	mut muts := []bool
 	for p.tok.kind != .rpar {
 		if p.tok.kind == .key_mut {
 			p.check(.key_mut)
+			muts << true
+		}
+		else {
+			muts << false
 		}
 		e,_ := p.expr(0)
 		args << e
@@ -42,7 +48,7 @@ pub fn (p mut Parser) call_args() []ast.Expr {
 		}
 	}
 	p.check(.rpar)
-	return args // ,table.void_ti
+	return args, muts
 }
 
 fn (p mut Parser) fn_decl() ast.FnDecl {
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index bf3e823896..d43d9cb85a 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -57,7 +57,7 @@ pub fn parse_stmt(text string, table &table.Table, scope &ast.Scope) ast.Stmt {
 		pref: &pref.Preferences{}
 		scope: scope
 		// scope: &ast.Scope{start_pos: 0, parent: 0}
-		
+
 	}
 	p.init_parse_fns()
 	p.read_first_token()
@@ -333,7 +333,7 @@ pub fn (p mut Parser) stmt() ast.Stmt {
 			return ast.ExprStmt{
 				expr: expr
 				// typ: typ
-				
+
 			}
 		}
 	}
@@ -632,7 +632,7 @@ pub fn (p mut Parser) name_expr() ast.Expr {
 		p.expr_mod = ''
 		return ast.EnumVal{
 			enum_name: enum_name // lp.prepend_mod(enum_name)
-			
+
 			val: val
 			pos: p.tok.position()
 		}
@@ -894,7 +894,7 @@ fn (p mut Parser) dot_expr(left ast.Expr, left_type table.Type) ast.Expr {
 	// Method call
 	if p.tok.kind == .lpar {
 		p.next()
-		args := p.call_args()
+		args,muts := p.call_args()
 		if p.tok.kind == .key_orelse {
 			p.next()
 			p.parse_block()
@@ -903,6 +903,7 @@ fn (p mut Parser) dot_expr(left ast.Expr, left_type table.Type) ast.Expr {
 			expr: left
 			name: field_name
 			args: args
+			muts:muts
 			pos: p.tok.position()
 		}
 		mut node := ast.Expr{}
@@ -1178,11 +1179,11 @@ fn (p mut Parser) if_expr() ast.Expr {
 		stmts: stmts
 		else_stmts: else_stmts
 		// typ: typ
-		
+
 		pos: pos
 		has_else: has_else
 		// left: left
-		
+
 	}
 	return node
 }
@@ -1603,10 +1604,10 @@ fn (p mut Parser) var_decl() ast.VarDecl {
 	node := ast.VarDecl{
 		name: name
 		expr: expr // p.expr(token.lowest_prec)
-		
+
 		is_mut: is_mut
 		// typ: typ
-		
+
 		pos: p.tok.position()
 	}
 	p.scope.register_var(node)
@@ -1725,7 +1726,7 @@ fn (p mut Parser) match_expr() ast.Expr {
 		blocks: blocks
 		match_exprs: match_exprs
 		// typ: typ
-		
+
 		cond: cond
 	}
 	return node