From 1582db1a0a54e104fb43f19ad121ad9a8d4e1032 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Tue, 10 Jan 2023 08:49:04 +0200
Subject: [PATCH] comptime: add support for `T is $Alias` and `T is $Function`
 (#16929)

---
 vlib/v/ast/ast.v                   |  4 ++
 vlib/v/ast/table.v                 |  6 +++
 vlib/v/fmt/fmt.v                   |  2 +
 vlib/v/gen/golang/golang.v         |  2 +
 vlib/v/parser/comptime.v           |  8 +++-
 vlib/v/tests/comptime_kinds_test.v | 59 ++++++++++++++++++++++++++++++
 6 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index da2e30519f..924b584278 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -126,6 +126,8 @@ pub enum ComptimeTypeKind {
 	array
 	sum_type
 	enum_
+	alias
+	function
 }
 
 pub struct ComptimeType {
@@ -144,6 +146,8 @@ pub fn (cty ComptimeType) str() string {
 		.array { '\$Array' }
 		.sum_type { '\$Sumtype' }
 		.enum_ { '\$Enum' }
+		.alias { '\$Alias' }
+		.function { '\$Function' }
 	}
 }
 
diff --git a/vlib/v/ast/table.v b/vlib/v/ast/table.v
index 9c1a372d7e..8c97e9cc47 100644
--- a/vlib/v/ast/table.v
+++ b/vlib/v/ast/table.v
@@ -2262,6 +2262,12 @@ pub fn (t &Table) is_comptime_type(x Type, y ComptimeType) bool {
 		.enum_ {
 			return x_kind == .enum_
 		}
+		.alias {
+			return x_kind == .alias
+		}
+		.function {
+			return x_kind == .function
+		}
 	}
 }
 
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index fbf839efd6..57e234fba7 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -731,6 +731,8 @@ pub fn (mut f Fmt) expr(node_ ast.Expr) {
 				.float { f.write('\$Float') }
 				.sum_type { f.write('\$Sumtype') }
 				.enum_ { f.write('\$Enum') }
+				.alias { f.write('\$Alias') }
+				.function { f.write('\$Function') }
 			}
 		}
 	}
diff --git a/vlib/v/gen/golang/golang.v b/vlib/v/gen/golang/golang.v
index 87b085d4bb..f902dbbf7d 100644
--- a/vlib/v/gen/golang/golang.v
+++ b/vlib/v/gen/golang/golang.v
@@ -659,6 +659,8 @@ pub fn (mut f Gen) expr(node_ ast.Expr) {
 				.float { f.write('\$Float') }
 				.sum_type { f.write('\$Sumtype') }
 				.enum_ { f.write('\$Enum') }
+				.alias { f.write('\$Alias') }
+				.function { f.write('\$Function') }
 			}
 		}
 	}
diff --git a/vlib/v/parser/comptime.v b/vlib/v/parser/comptime.v
index 0e2784eff7..cc109811a6 100644
--- a/vlib/v/parser/comptime.v
+++ b/vlib/v/parser/comptime.v
@@ -12,7 +12,7 @@ const (
 	supported_comptime_calls = ['html', 'tmpl', 'env', 'embed_file', 'pkgconfig', 'compile_error',
 		'compile_warn']
 	comptime_types           = ['Map', 'Array', 'Int', 'Float', 'Struct', 'Interface', 'Enum',
-		'Sumtype']
+		'Sumtype', 'Alias', 'Function']
 )
 
 pub fn (mut p Parser) parse_comptime_type() ast.ComptimeType {
@@ -40,6 +40,12 @@ pub fn (mut p Parser) parse_comptime_type() ast.ComptimeType {
 		'Float' {
 			cty = .float
 		}
+		'Alias' {
+			cty = .alias
+		}
+		'Function' {
+			cty = .function
+		}
 		'Array' {
 			cty = .array
 		}
diff --git a/vlib/v/tests/comptime_kinds_test.v b/vlib/v/tests/comptime_kinds_test.v
index f54ad3df12..66956ec90c 100644
--- a/vlib/v/tests/comptime_kinds_test.v
+++ b/vlib/v/tests/comptime_kinds_test.v
@@ -82,3 +82,62 @@ fn test_kind_struct() {
 	assert_not_struct[[]int]()
 	assert_not_struct[map[int]int]()
 }
+
+//
+
+type AliasOfAbc = Abc
+type AliasOfint = int
+type AliasOfstring = string
+
+fn assert_alias[T]() {
+	$if T is $Alias {
+		assert true
+	} $else {
+		assert false
+	}
+}
+
+fn assert_not_alias[T]() {
+	$if T is $Alias {
+		assert false
+	} $else {
+		assert true
+	}
+}
+
+fn test_kind_alias() {
+	assert_alias[AliasOfAbc]()
+	assert_alias[AliasOfint]()
+	assert_alias[AliasOfstring]()
+	//
+	assert_not_alias[int]()
+	assert_not_alias[f32]()
+	assert_not_alias[[]int]()
+	assert_not_alias[map[int]int]()
+	assert_not_alias[Abc]()
+}
+
+//
+fn assert_function[T](f T) {
+	$if T is $Function {
+		assert true
+	} $else {
+		assert false
+	}
+}
+
+fn assert_not_function[T](f T) {
+	$if T is $Function {
+		assert false
+	} $else {
+		assert true
+	}
+}
+
+fn test_kind_function() {
+	assert_function(test_kind_function)
+	assert_not_function(123)
+	assert_function('abc'.contains)
+	i := 5
+	assert_function(i.str) // TODO: 5.str currently leads to a cgen error
+}