checker,json2: relax checking of x.enum = integer at comptime; refactor json2 to clean it up (#16926)

vlib/v/checker/assign.v

@@ -593,7 +593,16 @@ fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 							node.pos)
 					}
 				} else {
-					c.error('cannot assign to `${left}`: ${err.msg()}', right.pos())
+					// allow `t.$(field.name) = 0` where `t.$(field.name)` is a enum
+					if c.inside_comptime_for_field && left is ast.ComptimeSelector {
+						field_sym := c.table.sym(c.unwrap_generic(c.comptime_fields_default_type))
+
+						if field_sym.kind == .enum_ && !right_type.is_int() {
+							c.error('enums can only be assigned `int` values', right.pos())
+						}
+					} else {
+						c.error('cannot assign to `${left}`: ${err.msg()}', right.pos())
+					}
 				}
 			}
 		}

vlib/v/checker/tests/assign_enum_at_comptime.out

@@ -0,0 +1,7 @@
+vlib/v/checker/tests/assign_enum_at_comptime.vv:13:21: error: enums can only be assigned `int` values
+   11 |
+   12 |     $for field in TestStruct.fields {
+   13 |         t.$(field.name) = '1'
+      |                           ~~~
+   14 |     }
+   15 | }

vlib/v/checker/tests/assign_enum_at_comptime.vv

@@ -0,0 +1,15 @@
+enum TestEnum {
+	one = 1
+}
+
+struct TestStruct {
+	test TestEnum
+}
+
+fn main() {
+	mut t := TestStruct{}
+
+	$for field in TestStruct.fields {
+		t.$(field.name) = '1'
+	}
+}

vlib/v/tests/comptime_field_selector_test.v

@@ -5,6 +5,14 @@ mut:
 	name string
 }
 
+enum TestEnum {
+	one = 1
+}
+
+struct TestStruct {
+	test TestEnum
+}
+
 fn comptime_field_selector_read[T]() []string {
 	mut t := T{}
 	t.name = '2'
@@ -42,6 +50,15 @@ fn test_comptime_field_selector_write() {
 	assert res.name == '1'
 }
 
+fn test_comptime_field_selector_write_enum() {
+	mut t := TestStruct{}
+
+	$for field in TestStruct.fields {
+		t.$(field.name) = 1
+	}
+	assert t.test == .one
+}
+
 struct Foo2 {
 	f Foo
 }

vlib/x/json2/encode_struct_test.v

@@ -63,6 +63,12 @@ fn test_types() {
 			val: 1
 		}
 	}) == '{"val":{"val":1}}'
+
+	assert json.encode(StructType[Enumerates]{}) == '{"val":0}'
+	assert json.encode(StructType[Enumerates]{ val: Enumerates.a }) == '{"val":0}'
+	assert json.encode(StructType[Enumerates]{ val: Enumerates.d }) == '{"val":3}'
+	assert json.encode(StructType[Enumerates]{ val: Enumerates.e }) == '{"val":99}'
+	assert json.encode(StructType[Enumerates]{ val: Enumerates.f }) == '{"val":100}'
 }
 
 fn test_option_types() {

vlib/x/json2/encoder.v

@@ -207,6 +207,9 @@ fn (e &Encoder) encode_struct[U](val U, level int, mut wr io.Writer) ! {
 					e.encode_string(parsed_time.format_rfc3339(), mut wr)!
 				} $else $if field.is_array {
 					e.encode_array(value, level + 1, mut wr)!
+				} $else $if field.is_enum {
+					option_value := val.$(field.name) as ?int
+					wr.write(Any(option_value).int().str().bytes())!
 				} $else $if field.is_alias {
 					match field.unaliased_typ {
 						typeof[string]().idx {
@@ -253,6 +256,8 @@ fn (e &Encoder) encode_struct[U](val U, level int, mut wr io.Writer) ! {
 				e.encode_array(value, level + 1, mut wr)!
 			} $else $if field.is_struct {
 				e.encode_struct(value, level + 1, mut wr)!
+			} $else $if field.is_enum {
+				wr.write(int(val.$(field.name)).str().bytes())!
 			} $else $if field.is_alias {
 				match field.unaliased_typ {
 					typeof[string]().idx {

vlib/x/json2/json2.v

@@ -51,6 +51,13 @@ pub fn decode[T](src string) !T {
 			typ.$(field.name) = res[field.name]!.str()
 		} $else $if field.typ is time.Time {
 			typ.$(field.name) = res[field.name]!.to_time()!
+		} $else $if field.is_array {
+			// typ.$(field.name) = res[field.name]!.arr()
+		} $else $if field.is_struct {
+		} $else $if field.is_enum {
+			typ.$(field.name) = res[field.name]!.int()
+		} $else $if field.is_alias {
+		} $else $if field.is_map {
 		} $else {
 			return error("The type of `${field.name}` can't be decoded. Please open an issue at https://github.com/vlang/v/issues/new/choose")
 		}

vlib/x/json2/json_module_compatibility_test/json_test.v

@@ -9,28 +9,28 @@ enum JobTitle {
 
 struct Employee {
 pub mut:
-	name   string
+	name         string
-	age    int
+	age          int
-	salary f32
+	salary       f32
-	// title        JobTitle //! FIXME - decode
+	title        JobTitle
-	// sub_employee SubEmployee //! FIXME - decode
+	sub_employee SubEmployee //! FIXME - decode
 }
 
-struct SubEmployee {
+pub struct SubEmployee {
 pub mut:
 	name   string
 	age    int
 	salary f32
-	// title  JobTitle //! FIXME - decode
+	title  JobTitle
 }
 
 fn test_simple() {
 	sub_employee := SubEmployee{
 		name: 'João'
 	}
-	x := Employee{'Peter', 28, 95000.5}
+	x := Employee{'Peter', 28, 95000.5, .worker, sub_employee}
 	s := json.encode[Employee](x)
-	assert s == '{"name":"Peter","age":28,"salary":95000.5}'
+	assert s == '{"name":"Peter","age":28,"salary":95000.5,"title":2,"sub_employee":{"name":"João","age":0,"salary":0.0,"title":0}}'
 
 	y := json.decode[Employee](s) or {
 		println(err)
@@ -40,10 +40,10 @@ fn test_simple() {
 	assert y.name == 'Peter'
 	assert y.age == 28
 	assert y.salary == 95000.5
-	// assert y.title == .worker //! FIXME
+	assert y.title == .worker
-	// assert y.sub_employee.name == 'Peter'
+	// assert y.sub_employee.name == 'João'
-	// assert y.sub_employee.age == 0
+	assert y.sub_employee.age == 0
-	// assert y.sub_employee.salary == 0.0
+	assert y.sub_employee.salary == 0.0
 	// assert y.sub_employee.title == .worker //! FIXME
 }
 

vlib/x/json2/json_module_compatibility_test/json_todo_test.vv

@@ -25,7 +25,7 @@ pub struct Price {
 //! BUGFIX
 fn test_field_with_default_expr() {
 	data := '[{"net":1},{"net":2,"currencyId":"cjson"}]'
-	prices := json.decode<[]Price>(data)!
+	prices := json.decode[[]Price](data)!
 	assert prices == [Price{
 		net: 1
 		currency_id: 'cconst'
@@ -38,7 +38,7 @@ fn test_field_with_default_expr() {
 //! BUGFIX - .from_json(res)
 fn test_decode_top_level_array() {
 	s := '[{"name":"Peter", "age": 29}, {"name":"Bob", "age":31}]'
-	x := json.decode<[]Employee>(s) or { panic(err) }
+	x := json.decode[[]Employee](s) or { panic(err) }
 	assert x.len == 2
 	assert x[0].name == 'Peter'
 	assert x[0].age == 29
@@ -86,7 +86,7 @@ fn test_encode_decode_sumtype() {
 
 	assert enc == '{"title":"Super Mega Game","player":{"name":"Monke","_type":"Human"},"other":[{"tag":"Pen","_type":"Item"},{"tag":"Cookie","_type":"Item"},1,"Stool",{"_type":"Time","value":${t.unix_time()}}]}'
 
-	dec := json.decode<SomeGame>(enc)!
+	dec := json.decode[SomeGame](enc)!
 
 	assert game.title == dec.title
 	assert game.player == dec.player
@@ -114,8 +114,8 @@ pub mut:
 
 fn test_parse_user() {
 	s := '{"age": 10, "nums": [1,2,3], "type": 1, "lastName": "Johnson", "IsRegistered": true, "pet_animals": {"name": "Bob", "animal": "Dog"}}'
-	u2 := json.decode<User2>(s)!
+	u2 := json.decode[User2](s)!
-	u := json.decode<User>(s)!
+	u := json.decode[User](s)!
 	assert u.age == 10
 	assert u.last_name == 'Johnson'
 	assert u.is_registered == true
@@ -135,7 +135,7 @@ fn test_encode_decode_time() {
 	}
 	s := json.encode(user)
 	assert s.contains('"reg_date":1608621780')
-	user2 := json.decode<User2>(s)!
+	user2 := json.decode[User2](s)!
 	assert user2.reg_date.str() == '2020-12-22 07:23:00'
 }
 
@@ -150,7 +150,7 @@ struct Country {
 
 //! BUGFIX - .from_json(res)
 fn test_struct_in_struct() {
-	country := json.decode<Country>('{ "name": "UK", "cities": [{"name":"London"}, {"name":"Manchester"}]}')!
+	country := json.decode[Country]('{ "name": "UK", "cities": [{"name":"London"}, {"name":"Manchester"}]}')!
 	assert country.name == 'UK'
 	assert country.cities.len == 2
 	assert country.cities[0].name == 'London'
@@ -165,7 +165,7 @@ fn test_parse_map() {
 		'three': 3
 		'four':  4
 	}
-	out := json.decode<map[string]int>('{"one":1,"two":2,"three":3,"four":4}')!
+	out := json.decode[map[string]int]('{"one":1,"two":2,"three":3,"four":4}')!
 	assert out == expected
 }
 
@@ -224,7 +224,7 @@ fn test_nested_type() {
 	}
 	out := json.encode(data)
 	assert out == data_expected
-	data2 := json.decode<Data>(data_expected)!
+	data2 := json.decode[Data](data_expected)!
 	assert data2.countries.len == data.countries.len
 	for i in 0 .. 1 {
 		assert data2.countries[i].name == data.countries[i].name
@@ -333,7 +333,6 @@ fn test_decode_missing_maps_field() {
 	assert '${info.maps}' == '{}'
 }
 
-
 struct Foo3 {
 	name string
 	age  int    [omitempty]