From efaec8be8ec5ff0764b91dfc37db9af25317302b Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2020 01:45:27 +0200
Subject: [PATCH] token/parser: var keyword

---
 vlib/v/checker/checker.v | 12 ++++++------
 vlib/v/gen/cgen.v        | 14 +++++++-------
 vlib/v/parser/fn.v       | 10 ++++++++--
 vlib/v/parser/parser.v   | 17 +++++++++--------
 vlib/v/token/token.v     |  2 ++
 5 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 6a60ec8acd..2ca1dba69d 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -386,9 +386,9 @@ pub fn (c mut Checker) call_fn(call_expr mut ast.CallExpr) table.Type {
 	// check for arg (var) of fn type
 	if !found {
 		scope := c.file.scope.innermost(call_expr.pos.pos)
-		if var := scope.find_var(fn_name) {
-			if var.typ != 0 {
-				vts := c.table.get_type_symbol(var.typ)
+		if v := scope.find_var(fn_name) {
+			if v.typ != 0 {
+				vts := c.table.get_type_symbol(v.typ)
 				if vts.kind == .function {
 					info := vts.info as table.FnType
 					f = info.func
@@ -1018,14 +1018,14 @@ pub fn (c mut Checker) expr(node ast.Expr) table.Type {
 		}
 		ast.Assoc {
 			scope := c.file.scope.innermost(it.pos.pos)
-			var := scope.find_var(it.var_name) or {
+			v := scope.find_var(it.var_name) or {
 				panic(err)
 			}
 			for i, _ in it.fields {
 				c.expr(it.exprs[i])
 			}
-			it.typ = var.typ
-			return var.typ
+			it.typ = v.typ
+			return v.typ
 		}
 		ast.BoolLiteral {
 			return table.bool_type
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 3abbc3e2a0..94e00d6c7e 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -827,16 +827,16 @@ fn (g mut Gen) free_scope_vars(pos int) {
 				// // TODO why 0?
 				// continue
 				// }
-				var := *it
-				sym := g.table.get_type_symbol(var.typ)
-				is_optional := table.type_is(var.typ, .optional)
+				v := *it
+				sym := g.table.get_type_symbol(v.typ)
+				is_optional := table.type_is(v.typ, .optional)
 				if sym.kind == .array && !is_optional {
-					g.writeln('array_free($var.name); // autofreed')
+					g.writeln('array_free($v.name); // autofreed')
 				}
 				if sym.kind == .string && !is_optional {
 					// Don't free simple string literals.
-					t := typeof(var.expr)
-					match var.expr {
+					t := typeof(v.expr)
+					match v.expr {
 						ast.StringLiteral {
 							g.writeln('// str literal')
 							continue
@@ -848,7 +848,7 @@ fn (g mut Gen) free_scope_vars(pos int) {
 							continue
 						}
 					}
-					g.writeln('string_free($var.name); // autofreed')
+					g.writeln('string_free($v.name); // autofreed')
 				}
 			}
 			else {}
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index 0786ca882d..bec1abf460 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -102,10 +102,16 @@ fn (p mut Parser) fn_decl() ast.FnDecl {
 	mut rec_mut := false
 	mut args := []table.Arg
 	if p.tok.kind == .lpar {
+		p.next()		// (
 		is_method = true
-		p.next()
+		rec_mut = p.tok.kind == .key_var
+		if rec_mut {
+			p.next()			// `var`
+		}
 		rec_name = p.check_name()
-		rec_mut = p.tok.kind == .key_mut
+		if !rec_mut {
+			rec_mut = p.tok.kind == .key_mut
+		}
 		is_amp := p.peek_tok.kind == .amp
 		// if rec_mut {
 		// p.check(.key_mut)
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index e7a1d313ec..3e984f77ea 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -371,7 +371,7 @@ pub fn (p mut Parser) stmt() ast.Stmt {
 				pos: assert_pos
 			}
 		}
-		.key_mut, .key_static {
+		.key_mut, .key_static, .key_var {
 			return p.assign_stmt()
 		}
 		.key_for {
@@ -1081,7 +1081,7 @@ fn (p mut Parser) for_stmt() ast.Stmt {
 			pos: pos
 			is_inf: true
 		}
-	} else if p.tok.kind == .key_mut {
+	} else if p.tok.kind in [.key_mut, .key_var] {
 		p.error('`mut` is not required in for loops')
 	} else if p.peek_tok.kind in [.decl_assign, .assign, .semicolon] || p.tok.kind == .semicolon {
 		// `for i := 0; i < 10; i++ {`
@@ -1733,9 +1733,9 @@ fn (p mut Parser) return_stmt() ast.Return {
 fn (p mut Parser) parse_assign_lhs() []ast.Ident {
 	mut idents := []ast.Ident
 	for {
-		is_mut := p.tok.kind == .key_mut
+		is_mut := p.tok.kind == .key_mut || p.tok.kind == .key_var
 		if is_mut {
-			p.check(.key_mut)
+			p.next()
 		}
 		is_static := p.tok.kind == .key_static
 		if is_static {
@@ -1785,7 +1785,8 @@ fn (p mut Parser) assign_stmt() ast.Stmt {
 	is_decl := op == .decl_assign
 	for i, ident in idents {
 		if op == .decl_assign && scanner.contains_capital(ident.name) {
-			p.error_with_pos('variable names cannot contain uppercase letters, use snake_case instead', ident.pos)
+			p.error_with_pos('variable names cannot contain uppercase letters, use snake_case instead',
+				ident.pos)
 		}
 		known_var := p.scope.known_var(ident.name)
 		if !is_decl && !known_var {
@@ -1864,7 +1865,7 @@ fn (p mut Parser) global_decl() ast.GlobalDecl {
 fn (p mut Parser) match_expr() ast.MatchExpr {
 	match_first_pos := p.tok.position()
 	p.check(.key_match)
-	is_mut := p.tok.kind == .key_mut
+	is_mut := p.tok.kind in [.key_mut, .key_var]
 	mut is_sum_type := false
 	if is_mut {
 		p.next()
@@ -2069,7 +2070,7 @@ fn (p mut Parser) type_decl() ast.TypeDecl {
 fn (p mut Parser) assoc() ast.Assoc {
 	var_name := p.check_name()
 	pos := p.tok.position()
-	var := p.scope.find_var(var_name) or {
+	v := p.scope.find_var(var_name) or {
 		p.error('unknown variable `$var_name`')
 		return ast.Assoc{}
 	}
@@ -2094,7 +2095,7 @@ fn (p mut Parser) assoc() ast.Assoc {
 		fields: fields
 		exprs: vals
 		pos: pos
-		typ: var.typ
+		typ: v.typ
 	}
 }
 
diff --git a/vlib/v/token/token.v b/vlib/v/token/token.v
index a96b8a799c..a988a323e0 100644
--- a/vlib/v/token/token.v
+++ b/vlib/v/token/token.v
@@ -120,6 +120,7 @@ pub enum Kind {
 	key_pub
 	key_static
 	key_unsafe
+	key_var
 	keyword_end
 	_end_
 }
@@ -245,6 +246,7 @@ fn build_token_str() []string {
 	s[Kind.key_select] = 'select'
 	s[Kind.key_none] = 'none'
 	s[Kind.key_offsetof] = '__offsetof'
+	s[Kind.key_var] = 'var'
 	return s
 }