all: attr for enum fields (+ json encode/decode) (#18163)

vlib/builtin/builtin.v

@@ -111,6 +111,7 @@ pub struct EnumData {
 pub:
 	name  string
 	value i64
+	attrs []string
 }
 
 // FieldData holds information about a field. Fields reside on structs.

vlib/v/ast/ast.v

@@ -1296,6 +1296,7 @@ pub:
 	comments      []Comment // comment after Enumfield in the same line
 	next_comments []Comment // comments between current EnumField and next EnumField
 	has_expr      bool      // true, when .expr has a value
+	attrs         []Attr
 pub mut:
 	expr Expr // the value of current EnumField; 123 in `ename = 123`
 }

vlib/v/ast/str.v

@@ -512,7 +512,7 @@ pub fn (x Expr) str() string {
 			return "'${x.val}'"
 		}
 		TypeNode {
-			return 'TypeNode(${x.typ})'
+			return 'TypeNode(${global_table.type_str(x.typ)})'
 		}
 		TypeOf {
 			if x.is_type {

vlib/v/ast/types.v

@@ -193,6 +193,7 @@ pub:
 	is_multi_allowed bool
 	uses_exprs       bool
 	typ              Type
+	attrs            map[string][]Attr
 }
 
 [minify]

vlib/v/fmt/fmt.v

@@ -986,6 +986,10 @@ pub fn (mut f Fmt) enum_decl(node ast.EnumDecl) {
 			f.write(' = ')
 			f.expr(field.expr)
 		}
+		if field.attrs.len > 0 {
+			f.write(' ')
+			f.single_line_attrs(field.attrs, inline: true)
+		}
 		f.comments(field.comments, inline: true, has_nl: false, level: .indent)
 		f.writeln('')
 		f.comments(field.next_comments, inline: false, has_nl: true, level: .indent)

vlib/v/gen/c/comptime.v

@@ -942,6 +942,15 @@ fn (mut g Gen) comptime_for(node ast.ComptimeFor) {
 					} else {
 						g.writeln('${g.typ(g.comptime_for_field_type)}__${g.comptime_enum_field_value};')
 					}
+					enum_attrs := sym.info.attrs[val]
+					if enum_attrs.len == 0 {
+						g.writeln('\t${node.val_var}.attrs = __new_array_with_default(0, 0, sizeof(string), 0);')
+					} else {
+						attrs := cgen_attrs(enum_attrs)
+						g.writeln(
+							'\t${node.val_var}.attrs = new_array_from_c_array(${attrs.len}, ${attrs.len}, sizeof(string), _MOV((string[${attrs.len}]){' +
+							attrs.join(', ') + '}));\n')
+					}
 					g.stmts(node.stmts)
 					g.writeln('}')
 					i++

vlib/v/gen/c/json.v

@@ -205,7 +205,15 @@ fn (mut g Gen) gen_enum_to_str(utyp ast.Type, sym ast.TypeSymbol, enum_var strin
 	enc.writeln('${ident}switch (${enum_var}) {')
 	for val in (sym.info as ast.Enum).vals {
 		enc.write_string('${ident}\tcase ${enum_prefix}${val}:\t')
-		enc.writeln('${result_var} = json__encode_string(_SLIT("${val}")); break;')
+		// read [json:] attr from the Enum value
+		attr := g.table.enum_decls[sym.name].fields.filter(it.name == val)[0].attrs.find_first('json') or {
+			ast.Attr{}
+		}
+		if attr.has_arg {
+			enc.writeln('${result_var} = json__encode_string(_SLIT("${attr.arg}")); break;')
+		} else {
+			enc.writeln('${result_var} = json__encode_string(_SLIT("${val}")); break;')
+		}
 	}
 	enc.writeln('${ident}}')
 }
@@ -215,11 +223,19 @@ fn (mut g Gen) gen_str_to_enum(utyp ast.Type, sym ast.TypeSymbol, val_var string
 	enum_prefix := g.gen_enum_prefix(utyp.clear_flag(.option))
 	is_option := utyp.has_flag(.option)
 	for k, val in (sym.info as ast.Enum).vals {
-		if k == 0 {
-			dec.write_string('${ident}if (string__eq(_SLIT("${val}"), ${val_var}))\t')
-		} else {
-			dec.write_string('${ident}else if (string__eq(_SLIT("${val}"), ${val_var}))\t')
+		// read [json:] attr from the Enum value
+		attr := g.table.enum_decls[sym.name].fields.filter(it.name == val)[0].attrs.find_first('json') or {
+			ast.Attr{}
 		}
+		if k == 0 {
+			dec.write_string('${ident}if (string__eq(_SLIT("${val}"), ${val_var})')
+		} else {
+			dec.write_string('${ident}else if (string__eq(_SLIT("${val}"), ${val_var})')
+		}
+		if attr.has_arg {
+			dec.write_string(' || string__eq(_SLIT("${attr.arg}"), ${val_var})')
+		}
+		dec.write_string(')\t')
 		if is_option {
 			base_typ := g.base_type(utyp)
 			dec.writeln('_option_ok(&(${base_typ}[]){ ${enum_prefix}${val} }, ${result_var}, sizeof(${base_typ}));')

vlib/v/parser/parser.v

@@ -3922,6 +3922,7 @@ fn (mut p Parser) enum_decl() ast.EnumDecl {
 	// mut default_exprs := []ast.Expr{}
 	mut fields := []ast.EnumField{}
 	mut uses_exprs := false
+	mut enum_attrs := map[string][]ast.Attr{}
 	for p.tok.kind != .eof && p.tok.kind != .rcbr {
 		pos := p.tok.pos()
 		val := p.check_name()
@@ -3935,6 +3936,13 @@ fn (mut p Parser) enum_decl() ast.EnumDecl {
 			has_expr = true
 			uses_exprs = true
 		}
+		mut attrs := []ast.Attr{}
+		if p.tok.kind == .lsbr {
+			p.attributes()
+			attrs << p.attrs
+			enum_attrs[val] = attrs
+			p.attrs = []
+		}
 		fields << ast.EnumField{
 			name: val
 			pos: pos
@@ -3942,6 +3950,7 @@ fn (mut p Parser) enum_decl() ast.EnumDecl {
 			has_expr: has_expr
 			comments: p.eat_comments(same_line: true)
 			next_comments: p.eat_comments()
+			attrs: attrs
 		}
 	}
 	p.top_level_statement_end()
@@ -3983,6 +3992,7 @@ fn (mut p Parser) enum_decl() ast.EnumDecl {
 			is_multi_allowed: is_multi_allowed
 			uses_exprs: uses_exprs
 			typ: enum_type
+			attrs: enum_attrs
 		}
 		is_pub: is_pub
 	})

vlib/v/tests/enum_attr_test.v

@@ -0,0 +1,37 @@
+import json
+
+enum Foo {
+	yay  [json: 'A'; yay]
+	foo  [foo; json: 'B']
+}
+
+struct FooStruct {
+	item Foo
+}
+
+fn test_comptime() {
+	$for f in Foo.values {
+		println(f)
+		if f.value == Foo.yay {
+			assert f.attrs[0] == 'json: A'
+			assert f.attrs[1] == 'yay'
+		}
+		if f.value == Foo.foo {
+			assert f.attrs[1] == 'json: B'
+			assert f.attrs[0] == 'foo'
+		}
+	}
+}
+
+fn test_json_encode() {
+	assert dump(json.encode(Foo.yay)) == '"A"'
+	assert dump(json.encode(Foo.foo)) == '"B"'
+
+	assert dump(json.encode(FooStruct{ item: Foo.yay })) == '{"item":"A"}'
+	assert dump(json.encode(FooStruct{ item: Foo.foo })) == '{"item":"B"}'
+}
+
+fn test_json_decode() {
+	dump(json.decode(FooStruct, '{"item": "A"}')!)
+	dump(json.decode(FooStruct, '{"item": "B"}')!)
+}