diff --git a/syntax/fostr.sdf3 b/syntax/fostr.sdf3
index 4dc4569..c346eee 100644
--- a/syntax/fostr.sdf3
+++ b/syntax/fostr.sdf3
@@ -42,14 +42,18 @@ context-free syntax
   Ex.Stream    = <stream>
   Ex.Sum       = <<Ex> +  <Ex>> {left}
   Ex.Gets      = [[Ex] << [Ex]] {left}
+  Ex.DefGets   = [<<< [Ex]]
   Ex.To        = [[Ex] >> [Ex]] {left}
+  Ex.DefTo     = [[Ex] >>>]
 
   Ex           = <(<Ex>)> {bracket}
 
 context-free priorities
 
   Ex.To
+  > Ex.DefTo
   > Ex.Sum
+  > Ex.DefGets
   > Ex.Gets,
 
   // prevent cycle: no singletons
diff --git a/tests/basic.spt b/tests/basic.spt
index e1cadf9..494cafb 100644
--- a/tests/basic.spt
+++ b/tests/basic.spt
@@ -231,3 +231,15 @@ run desugar-fostr to TopLevel(Sequence([
   Terminate(Sum(Int("11"), To(Int("12"), Stream()))),
   To(To(Int("13"), Stream()), Stream())
 ]))
+
+test emit_several_default [[
+<<< 1 + 2; 3 >>>
+(4 + 5) >>> >> stream; stream << 6;
+<<< 7 << 75
+<<< 8
+  + (9+10);
+11 + 12 >>>; 13 >>>
+                >>>
+]] parse succeeds
+/** writes
+3399677527121313*/
diff --git a/tests/emit_several.fos b/tests/emit_several.fos
index c806fd3..e7cbac5 100644
--- a/tests/emit_several.fos
+++ b/tests/emit_several.fos
@@ -1,7 +1,7 @@
-stream << 1 + 2; 3 >> stream
-(4 + 5) >> stream; stream << 6;
-stream << 7 
-stream << 8
+<<< 1 + 2; 3 >>>
+(4 + 5) >>> >> stream; stream << 6;
+<<< 7 << 75
+<<< 8
   + (9+10);
-11 + 12 >> stream; 13 >> stream
-                      >> stream
+11 + 12 >>>; 13 >>>
+                >>>
diff --git a/tests/hw.fos b/tests/hw.fos
index 90fc0d4..19eade4 100644
--- a/tests/hw.fos
+++ b/tests/hw.fos
@@ -1 +1 @@
-stream << 'Hello,	world!'
+<<< 'Hello, world!'
diff --git a/trans/desugar.str b/trans/desugar.str
index bfb4ecf..7276f38 100644
--- a/trans/desugar.str
+++ b/trans/desugar.str
@@ -15,7 +15,9 @@ rules
 
   seqFlatten: Sequence(l) -> Sequence(<mapconcat(?Sequence(<id>) <+ ![<id>])>l)
   
+  defStream:  DefGets(x)  -> Gets(Stream(), x)
+  defStream:  DefTo(x)    -> To(x, Stream())
+
 strategies
 
-  desugar-fostr = bottomup(try(deISe <+ seqFlatten))
- 
\ No newline at end of file
+  desugar-fostr = bottomup(try(defStream <+ deISe <+ seqFlatten))
diff --git a/trans/haskell.str b/trans/haskell.str
index 560b29c..fc75a7b 100644
--- a/trans/haskell.str
+++ b/trans/haskell.str
@@ -19,7 +19,8 @@ rules
      returning the final value.
    */
 
-  hs: (_, TopLevel(val)) -> $[import System.IO
+  hs: (_, TopLevel(val)) -> $[-- Preamble from fostr
+  import System.IO
   data IOStream = StdIO
 
   gets :: Show b => a -> b -> IO a
diff --git a/trans/javascript.str b/trans/javascript.str
index 645cc63..1fd2900 100644
--- a/trans/javascript.str
+++ b/trans/javascript.str
@@ -2,13 +2,16 @@ module javascript
 imports libstrategolib signatures/- util
 
 rules
-  js: TopLevel(x) -> $[const Stdio = {
+  js: TopLevel(x) -> $[// Fostr preamble
+  const Stdio = {
     gets: v => { process.stdout.write(String(v)); return Stdio; },
   }
   function to(data, strm) {
     strm.gets(data);
     return data;
   }
+  // End of preamble
+
   [x]]
 
   js: Stream()     -> $[Stdio]
diff --git a/trans/python.str b/trans/python.str
index 7aa4e06..068f05a 100644
--- a/trans/python.str
+++ b/trans/python.str
@@ -2,7 +2,8 @@ module python
 imports libstrategolib signatures/- util
 rules
 
-  py: TopLevel(x) -> $[import sys
+  py: TopLevel(x) -> $[## Fostr preamble
+  import sys
   class StdioC:
     def gets(self, v):
       print(v, file=sys.stdout, end='')
@@ -11,6 +12,8 @@ rules
     strm.gets(data)
     return data
   Stdio = StdioC()
+  ## End of preamble
+
   [x]]
 
   py: Stream()     -> $[Stdio]