fmt: intelligent newlines for trailing arg syntax (#7748)

vlib/v/fmt/fmt.v

@@ -38,12 +38,13 @@ pub mut:
 	file               ast.File
 	did_imports        bool
 	is_assign          bool
-	auto_imports      []string // automatically inserted imports that the user does not need to specify
+	auto_imports       []string // automatically inserted imports that the user forgot to specify
 	import_pos         int      // position of the imports in the resulting string for later autoimports insertion
 	used_imports       []string // to remove unused imports
 	is_debug           bool
 	mod2alias          map[string]string // for `import time as t`, will contain: 'time'=>'t'
 	use_short_fn_args  bool
+	single_line_fields bool   // should struct fields be on a single line
 	it_name            string // the name to replace `it` with
 	inside_lambda      bool
 	is_mbranch_expr    bool // math a { x...y { } }
@@ -1263,6 +1264,7 @@ pub fn (mut f Fmt) wrap_long_line(penalty_idx int, add_indent bool) bool {
 }
 
 pub fn (mut f Fmt) call_args(args []ast.CallArg) {
+	f.single_line_fields = true
 	for i, arg in args {
 		if arg.is_mut {
 			f.write(arg.share.str() + ' ')
@@ -1275,6 +1277,7 @@ pub fn (mut f Fmt) call_args(args []ast.CallArg) {
 			f.write(', ')
 		}
 	}
+	f.single_line_fields = false
 }
 
 pub fn (mut f Fmt) or_expr(or_block ast.OrExpr) {
@@ -1646,8 +1649,8 @@ pub fn (mut f Fmt) call_expr(node ast.CallExpr) {
 	old_short_arg_state := f.use_short_fn_args
 	f.use_short_fn_args = false
 	if node.args.len > 0 && node.args.last().expr is ast.StructInit {
-		struct_typ := (node.args.last().expr as ast.StructInit).typ
+		struct_expr := node.args.last().expr as ast.StructInit
-		if struct_typ == table.void_type {
+		if struct_expr.typ == table.void_type {
 			f.use_short_fn_args = true
 		}
 	}
@@ -2068,17 +2071,23 @@ pub fn (mut f Fmt) struct_init(it ast.StructInit) {
 	} else {
 		use_short_args := f.use_short_fn_args
 		f.use_short_fn_args = false
-		mut multiline_short_args := it.pre_comments.len > 0
+		mut single_line_fields := f.single_line_fields
+		f.single_line_fields = false
+		if it.pos.line_nr < it.pos.last_line || it.pre_comments.len > 0 {
+			single_line_fields = false
+		}
 		if !use_short_args {
-			f.writeln('$name{')
+			f.write('$name{')
-		} else {
+			if single_line_fields {
-			if multiline_short_args {
+				f.write(' ')
+			}
+		}
+		fields_start := f.out.len
+		fields_loop: for {
+			if !single_line_fields {
 				f.writeln('')
-			}
-		}
-		init_start := f.out.len
 				f.indent++
-		short_args_loop: for {
+			}
 			f.comments(it.pre_comments, inline: true, has_nl: true, level: .keep)
 			if it.has_update_expr {
 				f.write('...')
@@ -2090,7 +2099,7 @@ pub fn (mut f Fmt) struct_init(it ast.StructInit) {
 				f.write('$field.name: ')
 				f.prefix_expr_cast_expr(field.expr)
 				f.comments(field.comments, inline: true, has_nl: false, level: .indent)
-				if use_short_args && !multiline_short_args {
+				if single_line_fields {
 					if i < it.fields.len - 1 {
 						f.write(', ')
 					}
@@ -2098,21 +2107,25 @@ pub fn (mut f Fmt) struct_init(it ast.StructInit) {
 					f.writeln('')
 				}
 				f.comments(field.next_comments, inline: false, has_nl: true, level: .keep)
-				if use_short_args && !multiline_short_args &&
+				if single_line_fields &&
 					(field.comments.len > 0 ||
 					field.next_comments.len > 0 || !expr_is_single_line(field.expr) || f.line_len > max_len.last()) {
-					multiline_short_args = true
+					single_line_fields = false
-					f.out.go_back_to(init_start)
+					f.out.go_back_to(fields_start)
-					f.line_len = init_start
+					f.line_len = fields_start
 					f.remove_new_line()
-					f.writeln('')
+					continue fields_loop
-					continue short_args_loop
 				}
 			}
 			break
 		}
+		if !single_line_fields {
 			f.indent--
+		}
 		if !use_short_args {
+			if single_line_fields {
+				f.write(' ')
+			}
 			f.write('}')
 		}
 	}

vlib/v/fmt/tests/fn_trailing_arg_syntax_keep.vv

@@ -13,10 +13,14 @@ struct Baz {
 
 fn main() {
 	bar_func(x: 'bar', y: 13, z: 42)
+	bar_func(
+		x: 'bar'
+		y: 13
+		z: 42
+	)
 	foo_func(Baz{
 		x: 'Baz as Foo sumtype'
 	})
-	bar_func(x: 'bar', y: 2, z: 3, a: 4)
 	func_from_other_file(val: 'something')
 	bar_func(
 		// pre comment
@@ -43,8 +47,6 @@ fn main() {
 	)
 }
 
-fn bar_func(bar Bar) {
+fn bar_func(bar Bar) {}
-}
 
-fn foo_func(f Foo) {
+fn foo_func(f Foo) {}
-}

vlib/v/parser/struct.v

@@ -408,11 +408,7 @@ fn (mut p Parser) struct_init(short_syntax bool) ast.StructInit {
 		update_expr: update_expr
 		update_expr_comments: update_expr_comments
 		has_update_expr: has_update_expr
-		pos: token.Position{
+		pos: first_pos.extend_with_last_line(last_pos, p.tok.line_nr)
-			line_nr: first_pos.line_nr
-			pos: first_pos.pos
-			len: last_pos.pos - first_pos.pos + last_pos.len
-		}
 		is_short: no_keys
 		pre_comments: pre_comments
 	}

vlib/vweb/tests/vweb_test.v

@@ -197,9 +197,12 @@ fn test_http_client_shutdown_does_not_work_without_a_cookie() {
 fn testsuite_end() {
 	// This test is guaranteed to be called last.
 	// It sends a request to the server to shutdown.
-	x := http.fetch('http://127.0.0.1:$sport/shutdown', method: .get, cookies: {
+	x := http.fetch('http://127.0.0.1:$sport/shutdown', 
+		method: .get
+		cookies: {
 			'skey': 'superman'
-		}) or {
+		}
+	) or {
 		assert err == ''
 		return
 	}