diff --git a/extra/modern/compiler/compiler.factor b/extra/modern/compiler/compiler.factor
new file mode 100644
index 0000000000..9da11528e2
--- /dev/null
+++ b/extra/modern/compiler/compiler.factor
@@ -0,0 +1,121 @@
+! Copyright (C) 2017 Doug Coleman.
+! See http://factorcode.org/license.txt for BSD license.
+USING: arrays assocs combinators combinators.short-circuit fry
+kernel lexer modern namespaces sequences sets strings ;
+IN: modern.compiler
+
+<<
+SYMBOL: left-decorators
+left-decorators [ HS{ } clone ] initialize
+>>
+<<
+: make-left-decorator ( string -- )
+    left-decorators get adjoin ;
+
+>>
+<<
+SYNTAX: \LEFT-DECORATOR: scan-token make-left-decorator ;
+>>
+
+LEFT-DECORATOR: delimiter
+LEFT-DECORATOR: deprecated
+LEFT-DECORATOR: final
+LEFT-DECORATOR: flushable
+LEFT-DECORATOR: foldable
+LEFT-DECORATOR: inline
+LEFT-DECORATOR: recursive
+
+: left-decorator? ( obj -- ? )
+    left-decorators get in? ;
+
+<<
+SYMBOL: arities
+arities [ H{ } clone ] initialize
+>>
+<<
+: make-arity ( n string -- )
+    arities get set-at ;
+>>
+<<
+SYNTAX: \ARITY: scan-token scan-token swap make-arity ;
+>>
+
+ARITY: \ALIAS: 2
+ARITY: \ARITY: 2
+ARITY: \BUILTIN: 1
+ARITY: \CONSTANT: 2
+ARITY: \DEFER: 1
+ARITY: \GENERIC#: 3
+ARITY: \GENERIC: 2
+ARITY: \HOOK: 3
+ARITY: \IN: 1
+ARITY: \INSTANCE: 2
+ARITY: \MAIN: 1
+ARITY: \MATH: 1
+ARITY: \MIXIN: 1
+ARITY: \PRIMITIVE: 2
+ARITY: \QUALIFIED-WITH: 2
+ARITY: \QUALIFIED: 1
+ARITY: \RENAME: 3
+ARITY: \SINGLETON: 1
+ARITY: \SLOT: 1
+ARITY: \SYMBOL: 1
+ARITY: \UNUSE: 1
+ARITY: \USE: 1
+
+: get-arity ( string -- n/f )
+    arities get at ;
+
+<<
+SYMBOL: variable-arities
+variable-arities [ H{ } clone ] initialize
+>>
+<<
+: make-variable-arity ( n string -- )
+    variable-arities get set-at ;
+>>
+<<
+SYNTAX: \VARIABLE-ARITY: scan-token scan-token swap make-arity ;
+>>
+
+VARIABLE-ARITY: \EXCLUDE: 2
+VARIABLE-ARITY: \FROM: 2
+VARIABLE-ARITY: \INTERSECTION: 1
+VARIABLE-ARITY: \PREDICATE: 3
+VARIABLE-ARITY: \SYNTAX: 1
+VARIABLE-ARITY: \TUPLE: 1
+VARIABLE-ARITY: \UNION: 1
+VARIABLE-ARITY: \WORD: 2
+
+VARIABLE-ARITY: \<CLASS: 3
+VARIABLE-ARITY: \<FUNCTOR: 2
+
+: matched-literal? ( obj -- ? )
+    dup array? [
+        {
+            [ ?first "[" tail? ]
+            [ ?first "{" tail? ]
+            [ ?first "(" tail? ]
+            [ { [ ?first ":" tail? ] [ ?last ";" tail? ] } 1&& ]
+        } 1||
+    ] [
+        drop f
+    ] if ;
+
+: (map-literals) ( obj quot: ( obj -- obj' ) -- seq )
+    over matched-literal? [
+        [ call drop ] [
+            '[
+                first3 [ [ _ (map-literals) ] map ] dip 3array
+            ] call
+        ] 2bi
+    ] [
+        call
+    ] if ; inline recursive
+
+: map-literals ( obj quot: ( obj -- obj' ) -- seq )
+    '[ _ (map-literals) ] map ; inline
+
+
+
+
diff --git a/extra/modern/modern.factor b/extra/modern/modern.factor
index b67efacb54..e8252f2a14 100644
--- a/extra/modern/modern.factor
+++ b/extra/modern/modern.factor
@@ -193,7 +193,6 @@ ERROR: unexpected-terminator n string slice ;
 
 ERROR: colon-word-must-be-all-uppercase-or-lowercase n string word ;
 : read-colon ( n string slice -- n' string colon )
-    
     {
         { [ dup strict-upper? ] [ strict-upper on read-til-semicolon strict-upper off ] }
         { [ dup ":" tail? ] [ dup ":" head? [ read-lowercase-colon ] unless ] } ! :foo: vs foo: