diff --git a/bin/extract_tests.xsh b/bin/extract_tests.xsh
index 422acb1..1d8c59f 100644
--- a/bin/extract_tests.xsh
+++ b/bin/extract_tests.xsh
@@ -13,9 +13,6 @@ DESTINATION = 'tests/extracted'
 # Extension for extracted files:
 EXT = 'fos'
 
-# Extension for desired input:
-INP = 'in'
-
 # Extension for expectations:
 EXP = 'expect'
 
@@ -37,11 +34,6 @@ for path in TEST_LIST:
     expath = destdir / f"{name}.{EXT}"
     expath.write_text(example)
     echo Wrote @(expath)
-    im = re.search(r'/\*\*\s+accepts.*?\n([\s\S]*?)\*\*/', details[em.end():])
-    if im:
-      ipath = destdir / f"{name}.{INP}"
-      ipath.write_text(im[1])
-      echo "  ...and" @(ipath)
     xm = re.search(r'/\*\*\s+writes.*?\n([\s\S]*?)\*\*/', details[em.end():])
     if xm:
       xpath = destdir / f"{name}.{EXP}"
diff --git a/bin/run_tests b/bin/run_tests
index da49485..90ccaa7 100755
--- a/bin/run_tests
+++ b/bin/run_tests
@@ -9,14 +9,8 @@ diffed=0
 for dir in tests/extracted/*; do
   for file in $dir/*.$ext; do
     ((total++))
-    if [[ -f ${file%.*}.in ]]; then
-       cat ${file%.*}.in | $command $file > $file.out
-       result=$?
-    else
-       $command $file > $file.out
-       result=$?
-    fi
-    if [[ $result -ne 0 ]]; then
+    $command $file > $file.out
+    if [[ $? -ne 0 ]]; then
       echo ERROR: $command $file failed.
       ((failed++))
     else
diff --git a/mkdocs.yml b/mkdocs.yml
index c2d5242..e316a98 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -9,7 +9,7 @@ plugins:
 - search
 - semiliterate:
     ignore_folders: [target, lib]
-    exclude_extensions: ['.o', '.hi', '.cmi', '.cmo']
+    exclude_extensions: ['.o', '.hi']
     extract_standard_markdown:
       terminate: <!-- /md -->
 theme:
diff --git a/syntax/fostr.sdf3 b/syntax/fostr.sdf3
index f782466..8624b58 100644
--- a/syntax/fostr.sdf3
+++ b/syntax/fostr.sdf3
@@ -42,13 +42,10 @@ context-free syntax
   Ex.EscString = STRING
   Ex.Stream    = <stream>
   Ex.Sum       = <<Ex> +  <Ex>> {left}
-  Ex.Concat    = <<Ex> ++ <Ex>> {left}
   Ex.Gets      = [[Ex] << [Ex]] {left}
   Ex.DefGets   = [<<< [Ex]]
   Ex.To        = [[Ex] >> [Ex]] {left}
   Ex.DefTo     = [[Ex] >>>]
-  Ex.Emits     = <<Ex>!>
-  Ex.DefEmits  = <!!>
 
   Ex           = <(<Ex>)> {bracket}
 
@@ -56,7 +53,7 @@ context-free priorities
 
   Ex.To
   > Ex.DefTo
-  > {Ex.Sum Ex.Concat}
+  > Ex.Sum
   > Ex.DefGets
   > Ex.Gets,
 
diff --git a/tests/basic.spt b/tests/basic.spt
index 3d5a4a6..a5e98c0 100644
--- a/tests/basic.spt
+++ b/tests/basic.spt
@@ -293,38 +293,4 @@ test emit_several_default [[
                 >>>
 ]] parse succeeds
 /** writes
-3399677527121313**/
-
-/** md
-### Streams are bidirectional
-
-So far we have only sent items to a stream. But we can extract them from
-streams as well, with the `!` postfix operator. `!!` all by itself abbreviates
-`stream!`, i.e., extraction from the standard stream. For example,
-
-```fostr
-**/
-
-/** md */ test custom_hw [[
-<<< "What is your name?\n"
-<<< 'Hello, ' ++ !!
-]] /* **/
-parse to TopLevel(Sequence([
-  DefGets(EscString("\"What is your name?\n\"")),
-  DefGets(Concat(LitString("'Hello, '"),DefEmits()))
-]))
-/** accepts
-Kilroy
-**/
-/** writes
-What is your name?
-Hello, Kilroy
-**/
-
-/** md
-```
-
-queries users for their name and then writes a customized greeting. It also
-illustrates the use of `++` for string concatenation, as opposed to `+` for
-(numerical) addition.
-**/
+3399677527121313*/
diff --git a/trans/desugar.str b/trans/desugar.str
index b22ebd8..7276f38 100644
--- a/trans/desugar.str
+++ b/trans/desugar.str
@@ -17,7 +17,6 @@ rules
   
   defStream:  DefGets(x)  -> Gets(Stream(), x)
   defStream:  DefTo(x)    -> To(x, Stream())
-  defStream:  DefEmits()  -> Emits(Stream())
 
 strategies
 
diff --git a/trans/haskell.str b/trans/haskell.str
index 0e0eb15..0b08716 100644
--- a/trans/haskell.str
+++ b/trans/haskell.str
@@ -23,7 +23,6 @@ rules
   import System.IO
   data IOStream = StdIO
 
-  -- Danger: These currently assume the stream is StdIO
   gets :: Show b => a -> b -> IO a
   gets s d = do
     putStr(show d)
@@ -34,10 +33,6 @@ rules
     putStr(d)
     return s
 
-  emit s = do
-    l <- getLine
-    return (l ++ "\n")
-
   main = do
     [<Preactions>()]return [val]]
 
@@ -46,7 +41,6 @@ rules
   hs: (_, LitString(x)) -> <haskLitString>x
   hs: (_, EscString(x)) -> x
   hs: (_, Sum(x, y))    -> $[([x] + [y])]
-  hs: (_, Concat(x, y)) -> $[([x] ++ [y])]
 
   hs: (Gets(_, xn), Gets(s, x)) -> v
     with v := <newname>"_fostr_get"
@@ -58,10 +52,6 @@ rules
   hs_gets: (s, xn, x ) -> $[[s] [<hs_getOp>xn] [x]]
   hs_getOp = get-type; (?STRING() < !"`getsStr`" + !"`gets`")
 
-  hs: (_, Emits(s)) -> v
-    with v := <newname>"_fostr_emitted"
-       ; <add-preactions>[$[[v] <- emit [s]]]
-
   hs: (_, Terminate(x)) -> $[[x];;]
   hs: (_, Sequence(l))  -> <last>l
   /* One drawback of using paramorphism is we have to handle lists
diff --git a/trans/javascript.str b/trans/javascript.str
index 9b596ad..3a847e2 100644
--- a/trans/javascript.str
+++ b/trans/javascript.str
@@ -3,41 +3,24 @@ imports libstrategolib signatures/- util
 
 rules
   js: TopLevel(x) -> $[// Fostr preamble
-  const _fostr_readline = require('readline');
-  const _fostr_events = require('events');
-  const _fostr_rl = _fostr_readline.createInterface({input: process.stdin});
   const Stdio = {
-    gets:  v => { process.stdout.write(String(v)); return Stdio; },
-    emit: async () => {
-            const [line] = await _fostr_events.once(_fostr_rl, 'line');
-            return line + "\n"; }
+    gets: v => { process.stdout.write(String(v)); return Stdio; },
   }
   function to(data, strm) {
     strm.gets(data);
     return data;
   }
-
-  const _fostr_body = async () => {
   // End of preamble
 
-    [x]
-
-  // Fostr coda
-    _fostr_rl.close()
-  }
-  _fostr_body();
-  ]
-    with line := "[line]"
+  [x]]
 
   js: Stream()     -> $[Stdio]
   js: Int(x)       -> x
   js: LitString(x) -> <javaLitString>x
   js: EscString(x) -> x
-  js: Sum(x, y)    -> $[[x] + [y]]
-  js: Concat(x, y) -> $[[x] + [y]]
+  js: Sum(x,y)     -> $[[x] + [y]]
   js: Gets(x, y)   -> $[[x].gets([y])]
   js: To(x, y)     -> $[to([x],[y])]
-  js: Emits(x)     -> $[(await [x].emit())]
   js: Terminate(x) -> x
   js: Sequence(l)  -> <join(|";\n")>l
 
diff --git a/trans/ocaml.str b/trans/ocaml.str
index 049dbf4..11fcdca 100644
--- a/trans/ocaml.str
+++ b/trans/ocaml.str
@@ -12,10 +12,9 @@ imports libstrategolib signatures/- util signature/TYPE analysis
 
 rules
   ml: (_, TopLevel(x)) -> $[(* fostr preamble *)
-  type stream = { getS: string -> stream; emitS: unit -> string }
+  type stream = { getS: string -> stream }
   let rec stdio = {
-    getS = (fun s -> print_string s; stdio);
-    emitS = (fun () -> (read_line ()) ^ "\n");
+    getS = (fun s -> print_string s; stdio)
   };;
   (* End of preamble *)
 
@@ -25,15 +24,11 @@ rules
   ml: (_, Int(x))       -> x
   ml: (_, LitString(x)) -> $[{|[<un-single-quote>x]|}]
   ml: (_, EscString(x)) -> x
-  ml: (_, Sum(x, y))    -> $[[x] + [y]]
-  ml: (_, Concat(x, y)) -> $[[x] ^ [y]]
-
+  ml: (_, Sum(x,y))     -> $[[x] + [y]]
   ml: (Gets(_,yn), Gets(x, y))
     -> $[([x]).getS ([<ml_str>(yn,y)])]
   ml: (To(xn,_),   To(x, y))
     -> $[let _fto = ([x]) in (ignore (([y]).getS ([<ml_str>(xn,"_fto")])); _fto)]
-  ml: (_, Emits(s))     -> $[[s].emitS ()]
-
   ml: (_, Terminate(x)) -> x
   ml: (_, Sequence(l))  -> <ml_seq>l
   
diff --git a/trans/python.str b/trans/python.str
index f42b1cb..6449417 100644
--- a/trans/python.str
+++ b/trans/python.str
@@ -8,8 +8,6 @@ rules
     def gets(self, v):
       print(v, file=sys.stdout, end='')
       return self
-    def emit(self):
-      return input() + "\n" # Python inconsistently strips when using input
   def to(data,strm):
     strm.gets(data)
     return data
@@ -23,10 +21,8 @@ rules
   py: LitString(x) -> $[r[x]]
   py: EscString(x) -> x
   py: Sum(x,y)     -> $[[x] + [y]]
-  py: Concat(x,y)  -> $[[x] + [y]]
   py: Gets(x, y)   -> $[[x].gets([y])]
   py: To(x, y)     -> $[to([x],[y])]
-  py: Emits(x)     -> $[[x].emit()]
   py: Terminate(x) -> $[[x];]
   py: Sequence(l)  -> <join(|"\n")>l
 
diff --git a/trans/statics.stx b/trans/statics.stx
index ce99bf7..340a1df 100644
--- a/trans/statics.stx
+++ b/trans/statics.stx
@@ -222,13 +222,6 @@ This pattern lets us specify error messages.
     type_Ex(e2) == STREAM() | error $[Items may only be sent to Streams.]@e2.
   /* **/
 
-  ty_Ex(Concat(e1, e2)) = STRING() :-
-    type_Ex(e1) == STRING() | error $[Expression [e1] not String in concat.]@e1,
-    type_Ex(e2) == STRING() | error $[Expression [e2] not String in concat.]@e2.
-
-  ty_Ex(Emits(e)) = STRING() :- // At the moment, only stream is stdio
-    type_Ex(e) == STREAM() | error $[Only Streams may emit items.]@e.
-
   /** md
 ```