cgen: initial option auto str support (#7004)

vlib/builtin/option.v

@@ -23,16 +23,6 @@ struct OptionBase {
 	// derived Option_xxx types
 }
 
-pub fn (o OptionBase) str() string {
-   if o.ok && !o.is_none {
-	  return 'Option{ valid }'
-   }
-   if o.is_none {
-	  return 'Option{ none }'
-   }
-   return 'Option{ error: "${o.error}" }'
-}
-
 // `fn foo() ?Foo { return foo }` => `fn foo() ?Foo { return opt_ok(foo); }`
 fn opt_ok2(data voidptr, mut option &OptionBase, size int) {
 	unsafe {

vlib/v/checker/check_types.v

@@ -305,7 +305,9 @@ pub fn (mut c Checker) symmetric_check(left table.Type, right table.Type) bool {
 }
 
 pub fn (c &Checker) get_default_fmt(ftyp table.Type, typ table.Type) byte {
-	if typ.is_float() {
+	if ftyp.has_flag(.optional) {
+		return `s`
+	} else if typ.is_float() {
 		return `g`
 	} else if typ.is_signed() || typ.is_any_int() {
 		return `d`
@@ -325,8 +327,7 @@ pub fn (c &Checker) get_default_fmt(ftyp table.Type, typ table.Type) byte {
 		}
 		if ftyp in [table.string_type, table.bool_type] ||
 			sym.kind in
-			[.enum_, .array, .array_fixed, .struct_, .map, .multi_return, .sum_type] || ftyp.has_flag(.optional) ||
-			sym.has_method('str') {
+			[.enum_, .array, .array_fixed, .struct_, .map, .multi_return, .sum_type] || sym.has_method('str') {
 			return `s`
 		} else {
 			return `_`

vlib/v/checker/checker.v

@@ -1510,10 +1510,6 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 	if fn_name in ['println', 'print'] && call_expr.args.len > 0 {
 		c.expected_type = table.string_type
 		call_expr.args[0].typ = c.expr(call_expr.args[0].expr)
-		// check optional argument
-		if call_expr.args[0].typ.has_flag(.optional) {
-			c.error('cannot print optional type', call_expr.args[0].expr.position())
-		}
 		/*
 		// TODO: optimize `struct T{} fn (t &T) str() string {return 'abc'} mut a := []&T{} a << &T{} println(a[0])`
 		// It currently generates:

vlib/v/checker/tests/print_optional_type_err.out

@@ -1,6 +0,0 @@
-vlib/v/checker/tests/print_optional_type_err.vv:3:13: error: cannot print optional type
-    1 | import os
-    2 | fn main() {
-    3 |     println(os.ls('.'))
-      |                ~~~~~~~
-    4 | }

vlib/v/checker/tests/print_optional_type_err.vv

@@ -1,4 +0,0 @@
-import os
-fn main() {
-	println(os.ls('.'))
-}

vlib/v/gen/auto_str_methods.v

@@ -42,7 +42,7 @@ fn (mut g Gen) gen_str_for_type_with_styp(typ table.Type, styp string) string {
 		return str_fn_name_no_ptr
 	}
 	already_generated_key := '$styp:$str_fn_name'
-	if !sym_has_str_method && already_generated_key !in g.str_types {
+	if !sym_has_str_method && already_generated_key !in g.str_types && !typ.has_flag(.optional) {
 		$if debugautostr ? {
 			eprintln('> gen_str_for_type_with_styp: |typ: ${typ:5}, ${sym.name:20}|has_str: ${sym_has_str_method:5}|expects_ptr: ${str_method_expects_ptr:5}|nr_args: ${str_nr_args:1}|fn_name: ${str_fn_name:20}')
 		}
@@ -90,9 +90,49 @@ fn (mut g Gen) gen_str_for_type_with_styp(typ table.Type, styp string) string {
 		}
 		return 'varg_$str_fn_name'
 	}
+	if typ.has_flag(.optional) {
+		option_already_generated_key := 'option_$already_generated_key'
+		if option_already_generated_key !in g.str_types {
+			g.gen_str_for_option(typ, styp, str_fn_name)
+			g.str_types << option_already_generated_key
+		}
+		return str_fn_name
+	}
 	return str_fn_name
 }
 
+fn (mut g Gen) gen_str_for_option(typ table.Type, styp string, str_fn_name string) {
+	parent_type := typ.clear_flag(.optional)
+	sym := g.table.get_type_symbol(parent_type)
+	sym_has_str_method, _, _ := sym.str_method_info()
+	sym_name := sym.name.replace('.', '__')
+	mut parent_str_fn_name := styp_to_str_fn_name(sym_name)
+	if !sym_has_str_method {
+		parent_styp := g.typ(parent_type)
+		parent_str_fn_name = g.gen_str_for_type_with_styp(parent_type, parent_styp)
+	}
+	g.type_definitions.writeln('string ${str_fn_name}($styp it); // auto')
+	g.auto_str_funcs.writeln('string ${str_fn_name}($styp it) { return indent_${str_fn_name}(it, 0); }')
+	g.type_definitions.writeln('string indent_${str_fn_name}($styp it, int indent_count); // auto')
+	g.auto_str_funcs.writeln('string indent_${str_fn_name}($styp it, int indent_count) {')
+	g.auto_str_funcs.writeln('\tstring res;')
+	g.auto_str_funcs.writeln('\tif (it.is_none) {')
+	g.auto_str_funcs.writeln('\t\tres = tos_lit("none");')
+	g.auto_str_funcs.writeln('\t} else if (it.ok) {')
+	if typ.is_string() {
+		g.auto_str_funcs.writeln('\t\tres = _STR("\'%.*s\\000\'", 2, ${parent_str_fn_name}(*($sym_name*)it.data));')
+	} else if sym.kind == .struct_ && !sym_has_str_method {
+		g.auto_str_funcs.writeln('\t\tres = indent_${parent_str_fn_name}(*($sym_name*)it.data, indent_count);')
+	} else {
+		g.auto_str_funcs.writeln('\t\tres = ${parent_str_fn_name}(*($sym_name*)it.data);')
+	}
+	g.auto_str_funcs.writeln('\t} else {')
+	g.auto_str_funcs.writeln('\t\tres = _STR("error: \'%.*s\\000\'", 2, it.v_error);')
+	g.auto_str_funcs.writeln('\t}')
+	g.auto_str_funcs.writeln('\treturn _STR("Option(%.*s\\000)", 2, res);')
+	g.auto_str_funcs.writeln('}')
+}
+
 fn (mut g Gen) gen_str_for_alias(info table.Alias, styp string, str_fn_name string) {
 	sym := g.table.get_type_symbol(info.parent_type)
 	sym_has_str_method, _, _ := sym.str_method_info()

vlib/v/gen/cgen.v

@@ -4742,11 +4742,6 @@ fn (mut g Gen) gen_expr_to_string(expr ast.Expr, etype table.Type) ?bool {
 				g.write(')')
 			}
 		}
-	} else if g.typ(typ).starts_with('Option') {
-		str_fn_name := 'OptionBase_str'
-		g.write('${str_fn_name}(*(OptionBase*)&')
-		g.expr(expr)
-		g.write(')')
 	} else {
 		str_fn_name := g.gen_str_for_type(typ)
 		g.write('${str_fn_name}(')

vlib/v/gen/str.v

@@ -269,6 +269,8 @@ fn (mut g Gen) string_inter_literal(node ast.StringInterLiteral) {
 		} else if typ == table.bool_type {
 			g.expr(expr)
 			g.write(' ? _SLIT("true") : _SLIT("false")')
+		} else if node.fmts[i] == `s` {
+			g.gen_expr_to_string(expr, typ)
 		} else if typ.is_number() || typ.is_pointer() || node.fmts[i] == `d` {
 			if typ.is_signed() && node.fmts[i] in [`x`, `X`, `o`] {
 				// convert to unsigned first befors C's integer propagation strikes
@@ -286,8 +288,6 @@ fn (mut g Gen) string_inter_literal(node ast.StringInterLiteral) {
 			} else {
 				g.expr(expr)
 			}
-		} else if node.fmts[i] == `s` {
-			g.gen_expr_to_string(expr, typ)
 		} else {
 			g.expr(expr)
 		}

vlib/v/tests/str_gen_test.v

@@ -290,3 +290,71 @@ fn test_multi_generic_struct() {
 	assert '$x' == 'MultiGenericStruct<TestStruct, TestStruct>{\n    t: TestStruct{\n        x: 0\n    }\n    x: TestStruct{\n        x: 0\n    }\n}'
 	assert x.str() == 'MultiGenericStruct<TestStruct, TestStruct>{\n    t: TestStruct{\n        x: 0\n    }\n    x: TestStruct{\n        x: 0\n    }\n}'
 }
+
+fn create_option_err() ?string {
+	return error('this is an error')
+}
+
+fn test_option_err() {
+	assert '$create_option_err()' == 'Option(error: \'this is an error\')'
+}
+
+fn create_option_none() ?string {
+	return none
+}
+
+fn test_option_none() {
+	assert '$create_option_none()' == 'Option(none)'
+}
+
+fn create_option_string() ?string {
+	return 'this is a string'
+}
+
+fn test_option_string() {
+	assert '$create_option_string()' == 'Option(\'this is a string\')'
+}
+
+fn create_option_int() ?int {
+	return 5
+}
+
+fn test_option_int() {
+	assert '$create_option_int()' == 'Option(5)'
+}
+
+fn create_option_array() ?[]int {
+	return [1, 2, 3]
+}
+
+fn test_option_array() {
+	assert '$create_option_array()' == 'Option([1, 2, 3])'
+}
+
+fn create_option_struct() ?TestStruct {
+	return TestStruct{}
+}
+
+fn test_option_struct() {
+	assert '$create_option_struct()' == 'Option(TestStruct{\n    x: 0\n})'
+}
+
+struct OptionWrapper {
+	x ?TestStruct
+}
+
+fn test_struct_with_option() {
+	w := OptionWrapper{}
+	assert '$w' == 'OptionWrapper{\n    x: Option(error: \'\')\n}'
+}
+
+/* TODO: doesn't work yet
+struct OptionWrapperInt {
+	x ?int
+}
+
+fn test_struct_with_option() {
+	w := OptionWrapperInt{}
+	assert '$w' == 'OptionWrapperInt{\n    x: Option(error: \'\')\n}'
+}
+*/