From c9f619dc72fa56d7e4b650e1d523baa69003c885 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Mon, 10 Feb 2020 14:42:57 +0100
Subject: [PATCH] v2: parse `filter()`

---
 cmd/v/v.v                | 29 +++++++++++------------------
 vlib/v/ast/ast.v         |  6 ++++++
 vlib/v/parser/comptime.v |  1 +
 vlib/v/parser/parser.v   | 19 +++++++++++++++++--
 4 files changed, 35 insertions(+), 20 deletions(-)
 create mode 100644 vlib/v/parser/comptime.v

diff --git a/cmd/v/v.v b/cmd/v/v.v
index 8e92662325..a3d5caa606 100644
--- a/cmd/v/v.v
+++ b/cmd/v/v.v
@@ -9,23 +9,19 @@ import (
 )
 
 const (
-	simple_cmd = [
-		'fmt',
-		'up',
-		'create',
-		'test', 'test-fmt', 'test-compiler',
-		'bin2v',
-		'repl',
-		'build-tools', 'build-examples', 'build-vbinaries'
-	]
+	simple_cmd = ['fmt',
+	'up',
+	'create',
+	'test', 'test-fmt', 'test-compiler',
+	'bin2v',
+	'repl',
+	'build-tools', 'build-examples', 'build-vbinaries']
 )
 
 fn main() {
 	arg := join_flags_and_argument()
-	command, option := get_basic_command_and_option(arg)
-
+	command,option := get_basic_command_and_option(arg)
 	is_verbose := '-verbose' in arg || '--verbose' in arg
-
 	if '-v' in option || '--version' in option || command == 'version' {
 		// Print the version and exit.
 		version_hash := compiler.vhash()
@@ -35,29 +31,26 @@ fn main() {
 	if '-h' in option || '--help' in option || command == 'help' {
 		if is_verbose {
 			println(verbose_help_text)
-		} else {
+		}
+		else {
 			println(help_text)
 		}
 		return
 	}
-
 	if is_verbose {
 		eprintln('v    args: $arg')
 		eprintln('v command: $command')
 		eprintln('v options: $option')
 	}
-
 	if command in simple_cmd {
-		//External tools
+		// External tools
 		launch_tool(is_verbose, 'v' + command, command)
 		return
 	}
-
 	if command == 'run' || command == 'build' || command.ends_with('.v') || os.exists(command) {
 		compile(command, arg)
 		return
 	}
-
 	match command {
 		'', '-' {
 			if arg.len == 1 {
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index b36ee1ed9e..04b8795118 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -347,6 +347,12 @@ pub:
 	name string
 }
 
+// filter(), map()
+pub struct Lambda {
+pub:
+	name string
+}
+
 pub struct AssignStmt {
 pub:
 	left  []Ident
diff --git a/vlib/v/parser/comptime.v b/vlib/v/parser/comptime.v
new file mode 100644
index 0000000000..234e51e2bb
--- /dev/null
+++ b/vlib/v/parser/comptime.v
@@ -0,0 +1 @@
+module parser
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 73037358a1..3ad90b2b7c 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -665,9 +665,20 @@ fn (p mut Parser) index_expr(left ast.Expr) ast.Expr {
 	// return node,typ
 }
 
+fn (p mut Parser) filter(typ table.Type) {
+	p.table.register_var(table.Var{
+		name: 'it'
+		typ: typ
+	})
+}
+
 fn (p mut Parser) dot_expr(left ast.Expr, left_type table.Type) (ast.Expr,table.Type) {
 	p.next()
 	field_name := p.check_name()
+	if field_name == 'filter' {
+		p.table.open_scope()
+		p.filter(left_type)
+	}
 	// Method call
 	if p.tok.kind == .lpar {
 		p.next()
@@ -697,6 +708,9 @@ fn (p mut Parser) dot_expr(left ast.Expr, left_type table.Type) (ast.Expr,table.
 	typ := p.add_unresolved('${table.type_idx(left_type)}.$field_name', sel_expr)
 	mut node := ast.Expr{}
 	node = sel_expr
+	if field_name == 'filter' {
+		p.table.close_scope()
+	}
 	return node,typ
 }
 
@@ -1069,7 +1083,8 @@ fn (p mut Parser) struct_decl() ast.StructDecl {
 		// this allows overiding the builtins type
 		// with the real struct type info parsed from builtin
 		ret = p.table.register_builtin_type_symbol(t)
-	} else {
+	}
+	else {
 		ret = p.table.register_type_symbol(t)
 	}
 	if ret == -1 {
@@ -1256,7 +1271,7 @@ fn (p mut Parser) add_unresolved(key string, expr ast.Expr) table.Type {
 		p.table.unresolved_idxs[key] = idx
 		p.unresolved << expr
 	}
-	return table.new_type((-idx)-1)
+	return table.new_type((-idx) - 1)
 }
 
 fn verror(s string) {