progress on self hosting

TODO.FACTOR.txt

@@ -1,10 +1,8 @@
 + native:
 
-- gc when memory is tight
 - f >n: crashes
 - typecases: type error reporting bad
 - image output
-- 64-bit "bignums"
 - floats
 - {...} vectors
 - parsing should be parsing
@@ -48,6 +46,7 @@
 
 + misc:
 
+- compiled stack traces broken
 - should i -i inf -inf be parsing words?
 - namespace clone drops static var bindings
 - ditch map

factor/FactorReader.java

@@ -331,12 +331,7 @@ public class FactorReader
 		if(interp.getVocabulary(name) == null)
 			error("Undefined vocabulary: " + name);
 
-		Cons use = getUse();
+		setUse(new Cons(name,getUse()));
-
-		if(!Cons.contains(use,name))
-			use = new Cons(name,use);
-
-		setUse(use);
 	} //}}}
 
 	//{{{ parse() method

library/cross-compiler.factor

@@ -0,0 +1,178 @@
+! :folding=none:collapseFolds=1:
+
+! $Id$
+!
+! Copyright (C) 2004 Slava Pestov.
+! 
+! Redistribution and use in source and binary forms, with or without
+! modification, are permitted provided that the following conditions are met:
+! 
+! 1. Redistributions of source code must retain the above copyright notice,
+!    this list of conditions and the following disclaimer.
+! 
+! 2. Redistributions in binary form must reproduce the above copyright notice,
+!    this list of conditions and the following disclaimer in the documentation
+!    and/or other materials provided with the distribution.
+! 
+! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+IN: cross-compiler
+USE: arithmetic
+USE: kernel
+USE: lists
+USE: parser
+USE: stack
+USE: stdio
+USE: streams
+USE: strings
+USE: vectors
+USE: vectors
+USE: vocabularies
+USE: words
+
+IN: kernel
+DEFER: getenv
+DEFER: setenv
+DEFER: save-image
+DEFER: handle?
+DEFER: room
+
+IN: strings
+DEFER: str=
+DEFER: str-hashcode
+
+IN: io-internals
+DEFER: open-file
+DEFER: server-socket
+DEFER: close-fd
+DEFER: accept-fd
+DEFER: read-line-fd-8
+DEFER: write-fd-8
+DEFER: flush-fd
+DEFER: shutdown-fd
+
+IN: words
+DEFER: <word>
+DEFER: word-primitive
+DEFER: set-word-primitive
+DEFER: word-parameter
+DEFER: set-word-parameter
+DEFER: word-plist
+DEFER: set-word-plist
+
+IN: cross-compiler
+
+: primitives, ( -- )
+    1 [
+        execute
+        call
+        ifte
+        cons?
+        cons
+        car
+        cdr
+        rplaca
+        rplacd
+        vector?
+        <vector>
+        vector-length
+        set-vector-length
+        vector-nth
+        set-vector-nth
+        string?
+        str-length
+        str-nth
+        str-compare
+        str=
+        str-hashcode
+        index-of*
+        substring
+        sbuf?
+        <sbuf>
+        sbuf-length
+        set-sbuf-length
+        sbuf-nth
+        set-sbuf-nth
+        sbuf-append
+        sbuf>str
+        fixnum?
+        bignum?
+        +
+        -
+        *
+        /
+        mod
+        /mod
+        bitand
+        bitor
+        bitxor
+        bitnot
+        shift<
+        shift>
+        <
+        <=
+        >
+        >=
+        word?
+        <word>
+        word-primitive
+        set-word-primitive
+        word-parameter
+        set-word-parameter
+        word-plist
+        set-word-plist
+        drop
+        dup
+        swap
+        over
+        pick
+        nip
+        tuck
+        rot
+        >r
+        r>
+        eq?
+        getenv
+        setenv
+        open-file
+        garbage-collection
+        save-image
+        datastack
+        callstack
+        set-datastack
+        set-callstack
+        handle?
+        exit*
+        server-socket
+        close-fd
+        accept-fd
+        read-line-fd-8
+        write-fd-8
+        flush-fd
+        shutdown-fd
+        room
+    ] [
+        swap succ tuck primitive,
+    ] each drop ;
+
+: version, ( -- )
+    "version" [ "kernel" ] search version unit compound, ;
+
+: make-image ( -- )
+    #! Make an image for the C interpreter.
+    [
+        "/library/platform/native/boot.factor" run-resource
+    ] with-image
+
+    ! Uncomment this on sparc and powerpc.
+    ! "big-endian" on
+    "factor.image" write-image ;

library/debugger.factor

@@ -54,6 +54,10 @@ USE: unparser
 : in-parser? ( -- ? )
     "line" get "pos" get and ;
 
+: error-handler-hook
+    #! The game overrides this.
+    ;
+
 : default-error-handler ( error -- )
     #! Print the error and return to the top level.
     [
@@ -63,6 +67,8 @@ USE: unparser
         ":s :r :n :c show stacks at time of error." print
 
         java? [ ":j shows Java stack trace." print ] when
+        error-handler-hook
+
     ] when* ;
 
 : :s ( -- ) "error-datastack"  get . ;

library/httpd/http-common.factor

@@ -53,9 +53,7 @@ USE: url-encoding
 
 : httpd-error ( error -- )
     dup log-error
-    [ "text/html" response ] [ error-body ] cleave
+    <% dup "text/html" response % error-body % %> print ;
-    cat2
-    print ;
 
 : read-header-iter ( alist -- alist )
     read dup "" = [

library/httpd/responder.factor

@@ -1,4 +1,4 @@
-! :folding=indent:collapseFolds=0:
+! :folding=indent:collapseFolds=1:
 
 ! $Id$
 !

library/image.factor

@@ -184,7 +184,7 @@ DEFER: '
     object-tag here-as swap
     11 >header emit
     dup str-length emit
-    dup hashcode fixnum-mask bitand emit
+    dup hashcode ( fixnum-mask bitand ) emit
     pack-string
     pad ;
 
@@ -224,7 +224,7 @@ IN: cross-compiler
 
     dup word-name "name" swons ,
     dup word-vocabulary "vocabulary" swons ,
-    [ "parsing" get >boolean ] bind "parsing" swons ,
+    "parsing" swap word-property >boolean "parsing" swons ,
 
     ,] ' ;
 

library/init.factor

@@ -44,9 +44,13 @@ USE: strings
 ! on all other words already being defined.
 
 : init-search-path ( -- )
-    #! Sets up the default vocabularies.
+    ! For files
+    "user" "file-in" set
+    [ "user" "builtins" ] "file-use" set
+    ! For interactive
+    "user" "in" set
     [
-        "user" ! This is first
+        "user"
         "arithmetic"
         "builtins"
         "combinators"
@@ -72,10 +76,8 @@ USE: strings
         "vectors"
         "vocabularies"
         "words"
-        "scratchpad" ! This is last
+        "scratchpad"
-    ] "use" set
+    ] "use" set ;
-    ! New words go in 'user' vocabulary.
-    "user" "in" set ;
 
 : init-scratchpad ( -- )
     #! The contents of the scratchpad vocabulary is not saved

library/lists.factor

@@ -94,10 +94,6 @@ USE: stack
         2drop f
     ] ifte ;
 
-: count ( n -- [ 1 2 3 ... n ] )
-    #! If n <= 0, pushes the empty list.
-    [ [ ] times* ] cons expand ;
-
 : nth ( n list -- list[n] )
     #! Gets the nth element of a proper list by successively
     #! iterating down the cdr pointer.
@@ -165,32 +161,20 @@ USE: stack
     #! DESTRUCTIVE. Reverse the given list, without consing.
     f swap nreverse-iter ;
 
-~<< partition-iterI
+: partition-add ( obj ? ret1 ret2 -- ret1 ret2 )
-    R1 R2 A D C -- A C r:R1 r:R2 r:A r:D r:C >>~
+    >r >r [ r> cons r> ] [ r> r> swapd cons ] ifte ; inline
 
-~<< partition-iterT{
+: partition-step ( ret1 ret2 ref combinator car -- ret1 ret2 )
-    r:R1 r:R2 r:A r:D r:C -- A R1 r:R1 r:R2 r:D r:C >>~
+    >r 2swap r> -rot >r >r dup >r swap call r> swap r> r>
+    partition-add ; inline
 
-~<< }partition-iterT
+: partition-iter ( ret1 ret2 ref combinator list -- ret1 ret2 )
-    R1 r:R1X r:R2 r:D r:C -- R1 R2 D C >>~
+    dup [
-
+        3dup cdr >r >r >r
-~<< partition-iterF{
+        car partition-step
-    r:R1 r:R2 r:A r:D r:C -- A R2 r:R1 r:R2 r:D r:C >>~
+        r> r> r> partition-iter
-
-~<< }partition-iterF
-    R2 r:R1 r:R2X r:D r:C -- R1 R2 D C >>~
-
-: partition-iter ( ref ret1 ret2 list combinator -- ref ret1 ret2 )
-    #! Helper word for 'partition'.
-    over [
-        ! Note this ifte must be in tail position!
-        >r uncons r> partition-iterI >r >r dup r> r> call [
-            partition-iterT{ cons }partition-iterT partition-iter
     ] [
-            partition-iterF{ cons }partition-iterF partition-iter
+        3drop
-        ] ifte
-    ] [
-        2drop
     ] ifte ; inline interpret-only
 
 : partition ( ref list combinator -- list1 list2 )
@@ -200,19 +184,8 @@ USE: stack
     #! the first or second list.
     #! The combinator must have stack effect:
     #! ( ref element -- ? )
-    [ ] [ ] 2swap partition-iter rot drop ; inline interpret-only
+    swap >r >r >r [ ] [ ] r> r> r> partition-iter ;
-
+    inline interpret-only
-: remove ( obj list -- list )
-    #! Remove all occurrences of the object from the list.
-    dup [
-        2dup car = [
-            cdr remove
-        ] [
-            uncons swapd remove cons
-        ] ifte
-    ] [
-        nip
-    ] ifte ;
 
 : sort ( list comparator -- sorted )
     #! Sort the elements in a proper list using a comparator.
@@ -235,6 +208,18 @@ USE: stack
     #! Sorts the list into ascending numerical order.
     [ > ] sort ;
 
+: remove ( obj list -- list )
+    #! Remove all occurrences of the object from the list.
+    dup [
+        2dup car = [
+            cdr remove
+        ] [
+            uncons swapd remove cons
+        ] ifte
+    ] [
+        nip
+    ] ifte ;
+
 ! Redefined below
 DEFER: tree-contains?
 
@@ -293,13 +278,6 @@ DEFER: tree-contains?
         transp over >r >r call r> cons r>
     ] each drop nreverse ; inline interpret-only
 
-: map ( [ items ] [ code ] -- [ mapping ] )
-    #! Applies the code to each item, returns a list that
-    #! contains the result of each application.
-    #!
-    #! This combinator will not compile.
-    2list restack each unstack ; inline interpret-only
-
 : subset-add ( car pred accum -- accum )
     >r over >r call r> r> rot [ cons ] [ nip ] ifte ;
 

library/math/arithmetic.factor

@@ -57,14 +57,14 @@ USE: stack
     >=< call ; inline interpret-only
 
 : max ( x y -- z )
-    2dup > -rot ? ;
+    2dup > [ drop ] [ nip ] ifte ;
 
 : min ( x y -- z )
-    2dup < -rot ? ;
+    2dup < [ drop ] [ nip ] ifte ;
 
 : between? ( x min max -- ? )
     #! Push if min <= x <= max.
-    [ [ dup ] dip max ] dip min = ;
+    >r dupd max r> min = ;
 
 : sq dup * ; inline
 

library/platform/jvm/boot-sumo.factor

@@ -99,8 +99,9 @@ USE: parser
 "/library/telnetd.factor"                  run-resource ! telnetd
 
 !!! Java -> native VM image cross-compiler.
-"/library/platform/native/image.factor"          run-resource ! cross-compiler
+"/library/image.factor"                       run-resource ! cross-compiler
-"/library/platform/native/cross-compiler.factor" run-resource ! cross-compiler
+"/library/cross-compiler.factor"              run-resource ! cross-compiler
+"/library/platform/jvm/cross-compiler.factor" run-resource ! cross-compiler
 
 !!! HTTPD.
 "/library/httpd/url-encoding.factor"       run-resource ! url-encoding

library/platform/jvm/combinators.factor

@@ -39,3 +39,10 @@ USE: stack
     restack
         call
     unstack ; interpret-only
+
+: map ( [ items ] [ code ] -- [ mapping ] )
+    #! Applies the code to each item, returns a list that
+    #! contains the result of each application.
+    #!
+    #! This combinator will not compile.
+    2list restack each unstack ; inline interpret-only

library/platform/jvm/cross-compiler.factor

@@ -0,0 +1,53 @@
+! :folding=none:collapseFolds=1:
+
+! $Id$
+!
+! Copyright (C) 2004 Slava Pestov.
+! 
+! Redistribution and use in source and binary forms, with or without
+! modification, are permitted provided that the following conditions are met:
+! 
+! 1. Redistributions of source code must retain the above copyright notice,
+!    this list of conditions and the following disclaimer.
+! 
+! 2. Redistributions in binary form must reproduce the above copyright notice,
+!    this list of conditions and the following disclaimer in the documentation
+!    and/or other materials provided with the distribution.
+! 
+! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+IN: cross-compiler
+USE: arithmetic
+USE: kernel
+USE: lists
+USE: parser
+USE: stack
+USE: stdio
+USE: streams
+USE: strings
+USE: vectors
+USE: vectors
+USE: vocabularies
+USE: words
+
+: worddef, ( word -- )
+    dup compound-or-compiled? [
+        dup word-of-worddef swap compound>list compound,
+    ] [
+        drop
+    ] ifte ;
+
+: cross-compile ( quot -- )
+    [ dup worddef? [ worddef, ] [ drop ] ifte ] each ;
+
+: cross-compile-resource ( resource -- )
+    parse-resource cross-compile ;

library/platform/jvm/stack2.factor

@@ -65,7 +65,7 @@ USE: vectors
     clone set-callstack* ; interpret-only
 
 : clear ( -- )
-    #! Clear the datastack. For interactive use only; invoking this from a
+    #! Clear the datastack. For interactive use only; invoking
-    #! word definition will clobber any values left on the data stack by the
+    #! this from a word definition will clobber any values left
-    #! caller.
+    #! on the data stack by the caller.
     datastack* vector-clear ;

library/platform/native/arithmetic.factor

@@ -0,0 +1,24 @@
+! This file will go away very shortly!
+
+IN: arithmetic
+USE: combinators
+USE: kernel
+USE: logic
+USE: stack
+
+: integer? dup fixnum? swap bignum? or ;
+
+: max ( x y -- z )
+    2dup > [ drop ] [ nip ] ifte ;
+
+: min ( x y -- z )
+    2dup < [ drop ] [ nip ] ifte ;
+
+: between? ( x min max -- ? )
+    #! Push if min <= x <= max.
+    >r dupd max r> min = ;
+
+: pred 1 - ; inline
+: succ 1 + ; inline
+
+: neg 0 swap - ; inline

library/platform/native/boot.factor

@@ -47,6 +47,7 @@ primitives,
 [
     "/library/ansi.factor"
     "/library/assoc.factor"
+    "/library/cross-compiler.factor"
     "/library/combinators.factor"
     "/library/cons.factor"
     "/library/continuations.factor"
@@ -54,10 +55,12 @@ primitives,
     "/library/errors.factor"
     "/library/format.factor"
     "/library/hashtables.factor"
+    "/library/image.factor"
     "/library/init.factor"
     "/library/inspector.factor"
     "/library/inspect-vocabularies.factor"
     "/library/interpreter.factor"
+    "/library/lists.factor"
     "/library/list-namespaces.factor"
     "/library/logging.factor"
     "/library/logic.factor"
@@ -76,11 +79,12 @@ primitives,
     "/library/words.factor"
     "/library/math/math-combinators.factor"
     "/library/math/namespace-math.factor"
+    "/library/platform/native/arithmetic.factor"
+    "/library/platform/native/cross-compiler.factor"
     "/library/platform/native/errors.factor"
     "/library/platform/native/io-internals.factor"
     "/library/platform/native/stream.factor"
     "/library/platform/native/kernel.factor"
-    "/library/platform/native/image.factor"
     "/library/platform/native/namespaces.factor"
     "/library/platform/native/parse-numbers.factor"
     "/library/platform/native/parser.factor"
@@ -96,17 +100,6 @@ primitives,
 ] [
     cross-compile-resource
 ] each
-[
-    ! We don't include all of 'lists' or 'math' yet...
-    between? min max
-    append add remove contains unique
-    pred succ neg fib each nreverse nreverse-iter
-    max 2list length reverse nth list? 2rlist
-    all? clone-list clone-list-iter subset subset-iter
-    subset-add car= cdr= cons= cons-hashcode
-    tree-contains? =-or-contains? 
-    last* last inject integer?
-] [ worddef worddef, ] each
 
 version,
 

library/platform/native/cross-compiler.factor

@@ -26,169 +26,22 @@
 ! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 IN: cross-compiler
-USE: arithmetic
-USE: kernel
 USE: lists
+USE: namespaces
 USE: parser
-USE: stack
-USE: stdio
-USE: streams
-USE: strings
-USE: vectors
-USE: vectors
-USE: vocabularies
-USE: words
-
-IN: kernel
-DEFER: getenv
-DEFER: setenv
-DEFER: save-image
-DEFER: handle?
-DEFER: room
-
-IN: strings
-DEFER: str=
-DEFER: str-hashcode
-
-IN: io-internals
-DEFER: open-file
-DEFER: server-socket
-DEFER: close-fd
-DEFER: accept-fd
-DEFER: read-line-fd-8
-DEFER: write-fd-8
-DEFER: flush-fd
-DEFER: shutdown-fd
-
-IN: words
-DEFER: <word>
-DEFER: word-primitive
-DEFER: set-word-primitive
-DEFER: word-parameter
-DEFER: set-word-parameter
-DEFER: word-plist
-DEFER: set-word-plist
-
-IN: cross-compiler
-
-: primitives, ( -- )
-    1 [
-        execute
-        call
-        ifte
-        cons?
-        cons
-        car
-        cdr
-        rplaca
-        rplacd
-        vector?
-        <vector>
-        vector-length
-        set-vector-length
-        vector-nth
-        set-vector-nth
-        string?
-        str-length
-        str-nth
-        str-compare
-        str=
-        str-hashcode
-        index-of*
-        substring
-        sbuf?
-        <sbuf>
-        sbuf-length
-        set-sbuf-length
-        sbuf-nth
-        set-sbuf-nth
-        sbuf-append
-        sbuf>str
-        fixnum?
-        bignum?
-        +
-        -
-        *
-        /
-        mod
-        /mod
-        bitand
-        bitor
-        bitxor
-        bitnot
-        shift<
-        shift>
-        <
-        <=
-        >
-        >=
-        word?
-        <word>
-        word-primitive
-        set-word-primitive
-        word-parameter
-        set-word-parameter
-        word-plist
-        set-word-plist
-        drop
-        dup
-        swap
-        over
-        pick
-        nip
-        tuck
-        rot
-        >r
-        r>
-        eq?
-        getenv
-        setenv
-        open-file
-        garbage-collection
-        save-image
-        datastack
-        callstack
-        set-datastack
-        set-callstack
-        handle?
-        exit*
-        server-socket
-        close-fd
-        accept-fd
-        read-line-fd-8
-        write-fd-8
-        flush-fd
-        shutdown-fd
-        room
-    ] [
-        swap succ tuck primitive,
-    ] each drop ;
-
-: worddef, ( word -- )
-    dup compound-or-compiled? [
-        dup word-of-worddef swap compound>list compound,
-    ] [
-        drop
-    ] ifte ;
-
-: version, ( -- )
-    "version" [ "kernel" ] search
-    version unit
-    <compound>
-    worddef, ;
-
-: cross-compile ( quot -- )
-    [ dup worddef? [ worddef, ] [ drop ] ifte ] each ;
 
 : cross-compile-resource ( resource -- )
-    parse-resource cross-compile ;
+    <namespace> [
+        ! Replace ; with our own
+        "file-use" get
+        "cross-compiler-syntax" swons
+        "file-use" set
+        run-resource
+    ] bind ;
 
-: make-image ( -- )
+IN: cross-compiler-syntax
-    #! Make an image for the C interpreter.
+USE: builtins
-    [
-        "/library/platform/native/boot.factor" run-resource
-    ] with-image
 
-    ! Uncomment this on sparc and powerpc.
+: ; ( -- )
-    ! "big-endian" on
+    #! Cross-compile the just-read definition.
-    "factor.image" write-image ;
+    nreverse compound, ; parsing

library/platform/native/kernel.factor

@@ -110,5 +110,3 @@ IN: strings
 : >char ;
 : >upper ;
 : >lower ;
-IN: lists
-: sort ;

library/platform/native/parse-stream.factor

@@ -35,6 +35,7 @@ USE: namespaces
 USE: stack
 USE: stdio
 USE: streams
+USE: strings
 
 : next-line ( -- str )
     "parse-stream" get freadln
@@ -58,8 +59,8 @@ USE: streams
 
 : init-parser ( name -- seed )
     "parse-name" set
-    "user" "in" set
+    "file-in" get "in" set
-    [ "builtins" "user" ] "use" set
+    "file-use" get "use" set
     f ;
 
 : parse-stream ( name stream -- code )
@@ -72,3 +73,9 @@ USE: streams
 
 : run-file ( file -- )
     parse-file call ;
+
+: resource-path ( -- path )
+    "resource-path" get [ "." ] unless* ;
+
+: run-resource ( file -- )
+    resource-path swap cat2 run-file ;

library/platform/native/stack.factor

@@ -26,12 +26,20 @@
 ! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 IN: stack
+USE: vectors
 
 : 2drop ( x x -- ) drop drop ;
 : 3drop ( x x x -- ) drop drop drop ;
 : 2dup ( x y -- x y x y ) over over ;
+: 3dup ( x y z -- x y z x y z ) pick pick pick ;
 : 2swap ( x y z t -- z t x y ) rot >r rot r> ;
 : -rot ( x y z -- z x y ) rot rot ;
 : dupd ( x y -- x x y ) >r dup r> ;
 : swapd ( x y z -- y x z ) >r swap r> ;
 : transp ( x y z -- z y x ) swap rot ;
+
+: clear ( -- )
+    #! Clear the datastack. For interactive use only; invoking
+    #! this from a word definition will clobber any values left
+    #! on the data stack by the caller.
+    0 <vector> set-datastack ;