tmp(std,examples): remove err outport from For and Println

examples/99_bottles/main.neva

@@ -1,22 +1,16 @@
-def Main(start) (stop) {
-	App, Panic
-	---
-	:start -> app
-	app:err -> panic
-	app:sig -> :stop
-}
+import { fmt }
 
-def App(sig any) (sig any, err error) {
-	first For<int>{FirstLine}?
+def Main(start any) (stop any) {
+	first For<int>{FirstLine}
 	dec Dec<int>
-	second For<int>{SecondLine}?
+	second For<int>{SecondLine}
 	wait Wait
 	---
-	:sig -> 99..-1 -> first -> dec -> second -> wait -> :sig
+	:start -> 99..-1 -> first -> dec -> second -> wait -> :stop
 }
 
-def FirstLine(data int) (sig any, err error) {
-	p1 Println, p2 Println, p3 Printf?
+def FirstLine(data int) (sig any) {
+	p1 fmt.Println, p2 fmt.Println, p3 fmt.Printf?
 	---
 	:data -> switch {
 		0 -> { 'No more bottles of beer on the wall, no more bottles of beer.' -> p1 }
@@ -29,8 +23,8 @@ def FirstLine(data int) (sig any, err error) {
 	[p1, p2, p3] -> :sig
 }
 
-def SecondLine(data int) (sig any, err error) {
-	p1 Println, p2 Println, p3 Println, p4 Printf?
+def SecondLine(data int) (sig any) {
+	p1 fmt.Println, p2 fmt.Println, p3 fmt.Println, p4 fmt.Printf?
 	---
 	:data -> switch {
 		-1 -> { 'Go to the store and buy some more, 99 bottles of beer on the wall.' -> p1 }

std/builtin/streams.neva

@@ -1,11 +1,13 @@
-// basic stream operations
+// --- Basic operations ---
 
-// Wait blocks until last stream item arrive, then sends signal.
-pub def Wait(data stream<any>) (sig) {
-    If
+// Wait blocks until last stream item arrive, then sends a signal.
+pub def Wait(data stream<any>) (sig any) {
+    Del
     ---
-    :data -> .last -> if
-    if:then -> :sig
+    :data -> .last -> switch {
+        true -> :sig
+        _ -> del
+    }
 }
 
 // ArrPortToStream iterates over all array-inport's slots in order
@@ -144,18 +146,18 @@ pub def Accumulator<T>(init T, upd T, last bool) (cur T, res T)
 //
 // Like other iterators, it processes items one at a time without blocking the stream.
 // To wait for all items to be processed, use with `Wait`.
-pub def For<T>(data stream<T>) (res stream<T>, err error) {
+pub def For<T>(data stream<T>) (res stream<T>) {
     first First
     lock Lock<T>
-    handler IForEachHandler<T>?
+    handler IForEachHandler<T>
     ---
     :data -> [lock:data, first]
     [first:then, handler] -> lock:sig
     lock:data -> .data -> handler
 }
 
 // IForEachHandler is a dependency for For.
-pub interface IForEachHandler<T>(data T) (sig any, err error)
+pub interface IForEachHandler<T>(data T) (sig any)
 
 // `First` is a helper that allows to check if given stream item is the first one.
 def First(data stream<any>) (then bool, else bool) {

std/fmt/fmt.neva

@@ -1,6 +1,7 @@
+// TODO add err outport
 // Println prints to the standard output with a newline.
 #extern(println)
-pub def Println<T>(data T) (sig struct{}, err error)
+pub def Println<T>(data T) (sig struct{})
 
 // Printf replaces `$` with the corresponding argument
 // and prints to the standard output.