fmt: add support for `chan` types and operations (#6328)

vlib/sync/channel_opt_propagate_test.v

@@ -5,7 +5,7 @@ const (
 )
 
 fn get_val_from_chan(ch chan i64) ?i64 {
-	r := <-ch?
+	r := <-ch ?
 	return r
 }
 
@@ -33,7 +33,7 @@ fn test_channel_array_mut() {
 		chs[0] <- t
 		t = <-chs[1]
 	}
-	(&sync.Channel(chs[0])).close()
+	chs[0].close()
 	sem.wait()
 	assert t == 100 + num_iterations
 }

vlib/v/fmt/fmt.v

@@ -717,9 +717,17 @@ pub fn (mut f Fmt) prefix_expr_cast_expr(fexpr ast.Expr) {
 			is_pe_amp_ce = true
 			f.expr(ce)
 		}
+	} else if fexpr is ast.CastExpr {
+		last := f.out.cut_last(1)
+		if last != '&' {
+			f.out.write(last)
+		}
 	}
 	if !is_pe_amp_ce {
 		f.expr(fexpr)
+		if fexpr is ast.PrefixExpr {
+			f.or_expr(fexpr.or_block)
+		}
 	}
 }
 
@@ -1628,12 +1636,17 @@ fn expr_is_single_line(expr ast.Expr) bool {
 }
 
 pub fn (mut f Fmt) chan_init(mut it ast.ChanInit) {
-	if it.elem_type == 0 && it.typ > 0 {
 	info := f.table.get_type_symbol(it.typ).chan_info()
+	if it.elem_type == 0 && it.typ > 0 {
 		it.elem_type = info.elem_type
 	}
+	is_mut := info.is_mut
+	el_typ := if is_mut { it.elem_type.set_nr_muls(it.elem_type.nr_muls() - 1) } else { it.elem_type }
 	f.write('chan ')
-	f.write(f.type_to_str(it.elem_type))
+	if is_mut {
+		f.write('mut ')
+	}
+	f.write(f.type_to_str(el_typ))
 	f.write('{')
 	if it.has_cap {
 		f.write('cap: ')

vlib/v/fmt/tests/chan_ops_keep.vv

@@ -0,0 +1,65 @@
+import sync
+
+const (
+	num_iterations = 10000
+)
+
+struct St {
+	a int
+}
+
+fn get_val_from_chan(ch chan i64) ?i64 {
+	r := <-ch ?
+	return r
+}
+
+fn get_val_from_chan2(ch chan i64) ?i64 {
+	r := <-ch or {
+		println('error')
+		return error(err)
+	}
+	return r
+}
+
+// this function gets an array of channels for `i64`
+fn do_rec_calc_send(chs []chan i64, sem sync.Semaphore) {
+	mut msg := ''
+	for {
+		mut s := get_val_from_chan(chs[0]) or {
+			msg = err.str()
+			break
+		}
+		s++
+		chs[1] <- s
+	}
+	assert msg == 'channel closed'
+	sem.post()
+}
+
+fn test_channel_array_mut() {
+	mut chs := [chan i64{}, chan i64{cap: 10}]
+	sem := sync.new_semaphore()
+	go do_rec_calc_send(chs, sem)
+	mut t := i64(100)
+	for _ in 0 .. num_iterations {
+		chs[0] <- t
+		t = <-chs[1]
+	}
+	(&sync.Channel(chs[0])).close()
+	orr := &sync.Channel(chs[0])
+	chs[1].close()
+	ch := chan int{}
+	ch.close()
+	a := ch.cap
+	b := ch.len
+	c := ch[1].cap
+	d := ch[o].len
+	sem.wait()
+	assert t == 100 + num_iterations
+	ch2 := chan mut St{cap: 10}
+	go g(ch2)
+}
+
+fn g(ch chan mut St) {
+	return
+}

vlib/v/table/atypes.v

@@ -804,32 +804,36 @@ pub fn (table &Table) type_to_str(t Type) string {
 		map_start = 'map[string]'
 	}
 	if sym.kind == .chan || 'chan_' in res {
-		res = res.replace('chan_', '')
+		res = res.replace('chan_', 'chan ')
 	}
 	// mod.submod.submod2.Type => submod2.Type
-	if res.contains('.') {
-		vals := res.split('.')
+	mut parts := res.split(' ')
+	for i, _ in parts {
+		if parts[i].contains('.') {
+			vals := parts[i].split('.')
 			if vals.len > 2 {
-			res = vals[vals.len - 2] + '.' + vals[vals.len - 1]
+				parts[i] = vals[vals.len - 2] + '.' + vals[vals.len - 1]
 			}
-		if res.starts_with(table.cmod_prefix) ||
-			(sym.kind == .array && res.starts_with('[]' + table.cmod_prefix)) {
-			res = res.replace_once(table.cmod_prefix, '')
+			if parts[i].starts_with(table.cmod_prefix) ||
+				(sym.kind == .array && parts[i].starts_with('[]' + table.cmod_prefix)) {
+				parts[i] = parts[i].replace_once(table.cmod_prefix, '')
 			}
-		if sym.kind == .array && !res.starts_with('[]') {
-			res = '[]' + res
+			if sym.kind == .array && !parts[i].starts_with('[]') {
+				parts[i] = '[]' + parts[i]
 			}
-		if sym.kind == .map && !res.starts_with('map') {
-			res = map_start + res
+			if sym.kind == .map && !parts[i].starts_with('map') {
+				parts[i] = map_start + parts[i]
 			}
-		if sym.kind == .chan && !res.starts_with('chan') {
-			res = 'chan ' + res
 		}
+		if parts[i].contains('_mut') {
+			parts[i] = 'mut ' + parts[i].replace('_mut', '')
 		}
 		nr_muls := t.nr_muls()
 		if nr_muls > 0 {
-		res = strings.repeat(`&`, nr_muls) + res
+			parts[i] = strings.repeat(`&`, nr_muls) + parts[i]
 		}
+	}
+	res = parts.join(' ')
 	if t.has_flag(.optional) {
 		if sym.kind == .void {
 			res = '?'