From 9d4c943d648fc5624f752a3a3dcffd08eea4646a Mon Sep 17 00:00:00 2001
From: Nicolas Sauzede <nsauzede@laposte.net>
Date: Wed, 5 Feb 2020 06:12:33 +0100
Subject: [PATCH] compiler: add very simple nameof token to get type name as
 string

---
 vlib/compiler/expression.v        |  9 +++++++++
 vlib/compiler/tests/nameof_test.v | 16 ++++++++++++++++
 vlib/compiler/token.v             |  2 ++
 3 files changed, 27 insertions(+)
 create mode 100644 vlib/compiler/tests/nameof_test.v

diff --git a/vlib/compiler/expression.v b/vlib/compiler/expression.v
index c32c4d1f6e..20c48a9be8 100644
--- a/vlib/compiler/expression.v
+++ b/vlib/compiler/expression.v
@@ -813,6 +813,15 @@ fn (p mut Parser) factor() string {
 			// p.fgen('$sizeof_typ)')
 			return 'int'
 		}
+		.key_nameof {
+			p.next()
+			p.check(.lpar)
+			mut nameof_typ := p.get_type()
+			p.check(.rpar)
+			p.gen('tos3("$nameof_typ")')
+//			return 'byteptr'
+			return 'string'
+		}
 		.key_offsetof {
 			p.next()
 			p.check(.lpar)
diff --git a/vlib/compiler/tests/nameof_test.v b/vlib/compiler/tests/nameof_test.v
new file mode 100644
index 0000000000..9006181898
--- /dev/null
+++ b/vlib/compiler/tests/nameof_test.v
@@ -0,0 +1,16 @@
+
+fn simple<T>(p T) string {
+	tname := nameof(T)
+	println("Hello generic, I'm an [$tname]")
+	return tname
+}
+
+struct FunkyStruct{ }
+
+fn test_nameof_on_various_types_in_generic() {
+	assert simple(42) == "int"
+	assert simple(3.14) == "f32"
+	assert simple("FuBar") == "string"
+	assert simple(FunkyStruct{}) == "FunkyStruct"
+	assert simple(test_nameof_on_various_types_in_generic) == "fn ()"
+}
diff --git a/vlib/compiler/token.v b/vlib/compiler/token.v
index 60ed2b1c52..e0a4bce0f8 100644
--- a/vlib/compiler/token.v
+++ b/vlib/compiler/token.v
@@ -110,6 +110,7 @@ enum TokenKind {
 	key_select
 	key_sizeof
 	key_offsetof
+	key_nameof
 	key_struct
 	key_switch
 	key_true
@@ -240,6 +241,7 @@ fn build_token_str() []string {
 	s[TokenKind.key_select] = 'select'
 	s[TokenKind.key_none] = 'none'
 	s[TokenKind.key_offsetof] = '__offsetof'
+	s[TokenKind.key_nameof] = 'nameof'
 	return s
 }