fmt: format array elements line-by-line when nl after `[` (#5776)

vlib/v/fmt/fmt.v

@@ -1479,12 +1479,14 @@ pub fn (mut f Fmt) array_init(it ast.ArrayInit) {
 	f.write('[')
 	mut inc_indent := false
 	mut last_line_nr := it.pos.line_nr // to have the same newlines between array elements
+	mut break_after_each_element := false
 	for i, expr in it.exprs {
-		mut penalty := 3
 		line_nr := expr.position().line_nr
-		if last_line_nr < line_nr {
-			penalty--
+		if i == 0 && last_line_nr < line_nr {
+			 break_after_each_element = true
 		}
+		mut penalty := if break_after_each_element { 0 } else { 3 }
+		if penalty > 0 {
 			if i == 0 ||
 				it.exprs[i - 1] is ast.ArrayInit ||
 				it.exprs[i - 1] is ast.StructInit ||
@@ -1496,6 +1498,7 @@ pub fn (mut f Fmt) array_init(it ast.ArrayInit) {
 				expr is ast.CallExpr {
 				penalty--
 			}
+		}
 		is_new_line := f.wrap_long_line(penalty, !inc_indent)
 		if is_new_line && !inc_indent {
 			f.indent++

vlib/v/fmt/tests/consts_expected.vv

@@ -13,6 +13,12 @@ const (
 	one_line_supported  = ['windows', 'mac', 'macos', 'darwin', 'linux', 'freebsd', 'openbsd',
 		'netbsd', 'dragonfly', 'android', 'js', 'solaris', 'haiku', 'linux_or_macos']
 	another_const       = ['a', 'b', 'c', 'd', 'e', 'f']
+	multiline_const     = [
+		'first line',
+		'second line',
+		'third line',
+		'fourth line'
+	]
 )
 
 const (
@@ -24,3 +30,31 @@ const (
 pub const (
 	i_am_pub_const = true
 )
+
+fn main() {
+	a := [
+		[3, 5, 6],
+		[7, 9, 2]
+	]
+	b := [[
+		[2, 5, 8],
+		[5, 1, 3],
+		[2, 6, 0]
+	], [
+		[9, 4, 5],
+		[7, 2, 3],
+		[1, 2, 3]
+	]]
+	c := [
+		[
+			[2, 5, 8],
+			[5, 1, 3],
+			[2, 6, 0]
+		],
+		[
+			[9, 4, 5],
+			[7, 2, 3],
+			[1, 2, 3]
+		]
+	]
+}

vlib/v/fmt/tests/consts_input.vv

@@ -11,11 +11,13 @@ eulers=2.7182
 supported_platforms = ['windows', 'mac', 'macos', 'darwin', 'linux', 'freebsd', 'openbsd',
 		'netbsd', 'dragonfly', 'android', 'js', 'solaris', 'haiku', 'linux_or_macos']
 one_line_supported    = ['windows', 'mac', 'macos', 'darwin', 'linux', 'freebsd', 'openbsd', 'netbsd', 'dragonfly', 'android', 'js', 'solaris', 'haiku', 'linux_or_macos']
-another_const = [
-	'a', 'b'
+another_const = ['a', 'b'
 		'c', 'd', 'e'
 		'f'
 		]
+multiline_const = [
+		'first line',  'second line','third line',
+  'fourth line']		
 )
 
 const (
@@ -26,4 +28,26 @@ pub const (
 i_am_pub_const=true
 )
 
-
+fn main() {
+	a := [
+		[3,
+5,
+	6],[7,  9, 2]]
+b := [[
+[2,
+5,8],[   5,  1,
+3],[ 2, 6, 0]],[
+[9,
+4,5],[7,2,3],
+[1,
+2,3]]]
+c := [
+[
+[2,
+5,8],[   5,  1,
+3],[ 2, 6, 0]],[
+[9,
+4,5],[7,2,3],
+[1,
+2,3]]]
+}