Index: runtime/parrot/library/Parrot/HLLCompiler.pir
===================================================================
--- runtime/parrot/library/Parrot/HLLCompiler.pir	(revision 15893)
+++ runtime/parrot/library/Parrot/HLLCompiler.pir	(working copy)
@@ -17,6 +17,7 @@
     $P0 = newclass [ 'HLLCompiler' ]
     addattribute $P0, '$parsegrammar'
     addattribute $P0, '$astgrammar'
+    addattribute $P0, '$ostgrammar'
     addattribute $P0, '$!compsub'
 .end
 
@@ -71,6 +72,10 @@
 
 Accessor for the 'astgrammar' attribute.
 
+=item ostgrammar([string grammar])
+
+Accessor for the 'ostgrammar' attribute.
+
 =cut
 
 .sub 'parsegrammar' :method
@@ -86,7 +91,13 @@
     .return self.'attr'('$astgrammar', value, has_value)
 .end
 
+.sub 'ostgrammar' :method
+    .param string value        :optional
+    .param int has_value       :opt_flag
+    .return self.'attr'('$ostgrammar', value, has_value)
+.end
 
+
 =item compile(pmc code [, adverbs :slurpy :named])
 
 Compile C<source> according to any options given by
@@ -113,10 +124,13 @@
     .local pmc result
     result = self.'parse'(source, adverbs :flat :named)
     if target == 'parse' goto have_result
-    result = self.'ast'(result, adverbs :flat :named)
+    result = self.'astcompile'(result, adverbs :flat :named)
     if target == 'past' goto have_result
-    $P0 = compreg 'PAST'
-    result = $P0.'compile'(result, adverbs :flat :named)
+    result = self.'ostcompile'(result, adverbs :flat :named)
+    if target == 'post' goto have_result
+    result = self.'pircompile'(result, adverbs :flat :named)
+    if target == 'pir' goto have_result
+    result = self.'pirrun'(result, adverbs :flat :named)
   have_result:
     .return (result)
 .end
@@ -147,7 +161,7 @@
 .end
 
 
-=item ast(source [, adverbs :slurpy :named])
+=item astcompile(source [, adverbs :slurpy :named])
 
 Transform C<source> using the compiler's C<astgrammar>
 according to any options given by C<adverbs>, and return the
@@ -155,7 +169,7 @@
 
 =cut
 
-.sub 'ast' :method
+.sub 'astcompile' :method
     .param pmc source
     .param pmc adverbs         :slurpy :named
     .local string astgrammar_name
@@ -173,7 +187,50 @@
     throw $P0
 .end
 
+=item ostcompile(source [, adverbs :slurpy :named])
 
+Transform C<source> using the compiler's C<ostgrammar>
+according to any options given by C<adverbs>, and return the
+resulting ost.
+
+=cut
+
+.sub 'ostcompile' :method
+    .param pmc source
+    .param pmc adverbs         :slurpy :named
+    .local string ostgrammar_name
+    .local pmc ostgrammar, ostbuilder
+    ostgrammar_name = self.'ostgrammar'()
+    unless ostgrammar_name goto default_ostgrammar
+    $I0 = find_type ostgrammar_name
+    ostgrammar = new $I0
+    ostbuilder = ostgrammar.'apply'(source)
+    .return ostbuilder.'get'('post')
+
+  default_ostgrammar:
+    $P0 = compreg 'PAST'
+    .return $P0.'compile'(source, adverbs :flat :named)
+.end
+
+.sub 'pircompile' :method
+    .param pmc source
+    .param pmc adverbs         :slurpy :named
+
+    $P0 = compreg 'POST'
+    $P1 = $P0.'compile'(source, adverbs :flat :named)
+    .return ($P1)
+.end
+
+.sub 'pirrun' :method
+    .param pmc source
+    .param pmc adverbs         :slurpy :named
+
+    $P0 = compreg 'PIR'
+    $P1 = $P0(source)
+    .return ($P1)
+.end
+
+
 =item register(string name, pmc compsub)  # DEPRECATED
 
 (Deprecated.) Registers this compiler object as C<name> and 
Index: compilers/past-pm/POST/Compiler.pir
===================================================================
--- compilers/past-pm/POST/Compiler.pir	(revision 15893)
+++ compilers/past-pm/POST/Compiler.pir	(working copy)
@@ -27,13 +27,6 @@
     .param pmc post
     .param pmc adverbs         :slurpy :named
 
-    .local string target
-    target = adverbs['target']
-    target = downcase target
-    if target != 'post' goto compile_post
-    .return (post)
-
-  compile_post:
     $I0 = isa post, 'POST::Sub'
     if $I0 goto with_sub
     post = post.'new'('POST::Sub', post, 'name'=>'anon')
@@ -44,13 +37,7 @@
     post.'pir'()
 
     code = get_hll_global ['POST'], '$!subpir'
-    if target != 'pir' goto compile_pir
     .return (code)
-
-  compile_pir:
-    $P0 = compreg 'PIR'
-    $P0 = $P0(code)
-    .return ($P0)
 .end
 
 
Index: compilers/past-pm/PAST/Compiler.pir
===================================================================
--- compilers/past-pm/PAST/Compiler.pir	(revision 15893)
+++ compilers/past-pm/PAST/Compiler.pir	(working copy)
@@ -37,21 +37,12 @@
     .param pmc past
     .param pmc adverbs         :slurpy :named
 
-    .local string target
-    target = adverbs['target']
-    target = downcase target
-    if target == 'past' goto return_past
-    if target == 'parse' goto return_past
-
     .local pmc postgrammar, postbuilder, post
     postgrammar = new 'POST::Grammar'
     postbuilder = postgrammar.'apply'(past)
     post = postbuilder.'get'('root')
-    $P0 = compreg 'POST'
-    .return $P0.'compile'(post, adverbs :flat :named)
+    .return (post)
 
-  return_past:
-    .return (past)
 .end
 
 =back