Implement type param to map conversion.

nevkontakte · nevkontakte · commit 07690760b5d0 · 2023-11-01T20:42:32.000Z
diff --git a/compiler/prelude/types.js b/compiler/prelude/types.js
@@ -472,6 +472,8 @@ var $newType = (size, kind, string, named, pkg, exported, constructor) => {
             typ.convertFrom = (src) => $convertToStruct(src, typ);
             break;
         case $kindMap:
+            typ.convertFrom = (src) => $convertToMap(src, typ);
+            break;
         case $kindChan:
         case $kindFunc:
             break;
@@ -1190,4 +1192,14 @@ const $convertToArray = (src, dstType) => {
     // Since arrays are passed by value, the conversion result must be a copy
     // of the original value, even if it is the same type.
     return $clone(src.$val, dstType);
+};
+
+/**
+ * Convert to map types.
+ *
+ * dstType.kind must be $kindMap. Src must be a wrapped map value. Returned
+ * value will always be a bare JavaScript object representing the map.
+ */
+const $convertToMap = (src, dstType) => {
+    return src.$val;
 };
diff --git a/tests/typeparams/conversion_test.go b/tests/typeparams/conversion_test.go
@@ -56,6 +56,7 @@ type ( // Named types for use in conversion test cases.
 	sl     []byte
 	arr    [3]byte
 	arrPtr *[3]byte
+	m      map[string]string
 )
 
 type numeric interface {
@@ -257,6 +258,15 @@ func (tc arrayConversion[srcType, dstType]) Run(t *testing.T) {
 	checkConversion(t, tc.src, dstType(tc.src), tc.want)
 }
 
+type mapConversion[srcType ~map[string]string, dstType ~map[string]string] struct {
+	src  srcType
+	want dstType
+}
+
+func (tc mapConversion[srcType, dstType]) Run(t *testing.T) {
+	checkConversion(t, tc.src, dstType(tc.src), tc.want)
+}
+
 func TestConversion(t *testing.T) {
 	strVar := "abc"
 	stVar := st{s: "abc", i: 42}
@@ -359,6 +369,9 @@ func TestConversion(t *testing.T) {
 		}]{src: st{i: 42, s: "abc"}, want: st2{s: "abc", i: 42}},
 		// $convertToArray
 		arrayConversion[[3]byte, arr]{src: [3]byte{1, 2, 3}, want: arr{1, 2, 3}},
+		// $convertToMap
+		mapConversion[map[string]string, m]{src: map[string]string{"abc": "def"}, want: m{"abc": "def"}},
+		mapConversion[map[string]string, m]{src: nil, want: nil},
 	}
 
 	for _, test := range tests {
