v: fix anon struct option support (fix #23789) (fix #23824) (#23830)

Author: felipensp

vlib/v/ast/ast.v

@@ -431,6 +431,7 @@ pub:
 	global_pos       int = -1 // __global:
 	module_pos       int = -1 // module:
 	is_union         bool
+	is_option        bool
 	attrs            []Attr
 	pre_comments     []Comment
 	end_comments     []Comment

vlib/v/ast/str.v

@@ -186,7 +186,12 @@ fn (t &Table) stringify_fn_after_name(node &FnDecl, mut f strings.Builder, cur_m
 		f.write_string(param.name)
 		param_sym := t.sym(param.typ)
 		if param_sym.info is Struct && param_sym.info.is_anon {
-			f.write_string(' struct {')
+			if param.typ.has_flag(.option) {
+				f.write_string(' ?')
+			} else {
+				f.write_string(' ')
+			}
+			f.write_string('struct {')
 			for field in param_sym.info.fields {
 				f.write_string(' ${field.name} ${t.type_to_str(field.typ)}')
 				if field.has_default_expr {

vlib/v/fmt/struct.v

@@ -10,6 +10,9 @@ pub fn (mut f Fmt) struct_decl(node ast.StructDecl, is_anon bool) {
 	if node.is_pub && !is_anon {
 		f.write('pub ')
 	}
+	if node.is_option {
+		f.write('?')
+	}
 	if node.is_union {
 		f.write('union')
 	} else {

vlib/v/gen/c/cgen.v

@@ -6504,7 +6504,7 @@ fn (mut g Gen) write_types(symbols []&ast.TypeSymbol) {
 							}
 						}
 					}
-					g.struct_decl(sym.info, name, false)
+					g.struct_decl(sym.info, name, false, false)
 					struct_names[name] = true
 				}
 			}

vlib/v/gen/c/struct.v

@@ -77,7 +77,7 @@ fn (mut g Gen) struct_init(node ast.StructInit) {
 			g.write(')')
 		}
 	}
-	if is_anon {
+	if is_anon && !node.typ.has_flag(.option) {
 		if node.language == .v {
 			g.write('(${styp})')
 		}
@@ -541,7 +541,7 @@ fn (mut g Gen) zero_struct_field(field ast.StructField) bool {
 	return true
 }
 
-fn (mut g Gen) struct_decl(s ast.Struct, name string, is_anon bool) {
+fn (mut g Gen) struct_decl(s ast.Struct, name string, is_anon bool, is_option bool) {
 	if s.is_generic {
 		return
 	}
@@ -585,10 +585,11 @@ fn (mut g Gen) struct_decl(s ast.Struct, name string, is_anon bool) {
 		}
 	}
 	if is_anon {
+		option_prefix := if is_option { '_option_' } else { '' }
 		if s.is_shared {
-			g.type_definitions.write_string('\t__shared__${name}* ')
+			g.type_definitions.write_string('\t${option_prefix}__shared__${name}* ')
 		} else {
-			g.type_definitions.write_string('\t${name} ')
+			g.type_definitions.write_string('\t${option_prefix}${name} ')
 		}
 		return
 	} else if s.is_union {
@@ -671,7 +672,7 @@ fn (mut g Gen) struct_decl(s ast.Struct, name string, is_anon bool) {
 				if field_sym.info.is_anon {
 					field_is_anon = true
 					// Recursively generate code for this anon struct (this is the field's type)
-					g.struct_decl(field_sym.info, field_sym.cname, true)
+					g.struct_decl(field_sym.info, field_sym.cname, true, field.typ.has_flag(.option))
 					// Now the field's name
 					g.type_definitions.writeln(' ${field_name}${size_suffix};')
 				}

vlib/v/parser/parse_type.v

@@ -525,7 +525,11 @@ fn (mut p Parser) parse_type() ast.Type {
 	if p.tok.kind == .key_struct {
 		p.anon_struct_decl = p.struct_decl(true)
 		// Find the registered anon struct type, it was registered above in `p.struct_decl()`
-		return p.table.find_type_idx(p.anon_struct_decl.name)
+		mut typ := p.table.find_type_idx(p.anon_struct_decl.name)
+		if is_option {
+			typ = ast.new_type(typ).set_flag(.option)
+		}
+		return typ
 	}
 
 	language := p.parse_language()

vlib/v/parser/struct.v

@@ -14,6 +14,7 @@ fn (mut p Parser) struct_decl(is_anon bool) ast.StructDecl {
 	start_pos := p.tok.pos()
 	mut is_pub := p.tok.kind == .key_pub
 	mut is_shared := p.tok.kind == .key_shared
+	is_option := is_anon && p.prev_tok.kind == .question
 	if is_pub {
 		p.next()
 	}
@@ -436,6 +437,7 @@ fn (mut p Parser) struct_decl(is_anon bool) ast.StructDecl {
 		module_pos:       module_pos
 		language:         language
 		is_union:         is_union
+		is_option:        is_option
 		attrs:            if is_anon { []ast.Attr{} } else { attrs } // anon structs can't have attributes
 		pre_comments:     pre_comments
 		end_comments:     end_comments

vlib/v/tests/options/option_anon_struct_test.v

@@ -0,0 +1,23 @@
+struct Foo {
+	a ?struct {
+		name string
+	}
+}
+
+fn test_main() {
+	t := Foo{}
+	assert '${t}' == 'Foo{
+    a: Option(none)
+}'
+
+	t2 := Foo{
+		a: struct {
+			name: 'foo'
+		}
+	}
+	assert '${t2}' == "Foo{
+    a: Option(struct {
+        name: 'foo'
+    })
+}"
+}

vlib/v/tests/options/option_none_to_anon_struct_test.v

@@ -0,0 +1,16 @@
+fn opt(params ?struct { name string surname string }) {
+	if params == none {
+		assert '${params}' == 'Option(none)'
+	}
+	if params != none {
+		assert '${params}' == "struct {
+    name: 'foo'
+    surname: 'bar'
+}"
+	}
+}
+
+fn test_main() {
+	opt(none)
+	opt(struct { name: 'foo', surname: 'bar' })
+}