From 9c2e8abaca27d424600dc57f299d2f43adbf9eeb Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Sat, 6 Dec 2008 14:24:31 -0600 Subject: [PATCH 1/7] Enable more local DCE --- basis/stack-checker/known-words/known-words.factor | 3 --- 1 file changed, 3 deletions(-) diff --git a/basis/stack-checker/known-words/known-words.factor b/basis/stack-checker/known-words/known-words.factor index 94a434f31b..28634f2d44 100644 --- a/basis/stack-checker/known-words/known-words.factor +++ b/basis/stack-checker/known-words/known-words.factor @@ -99,21 +99,18 @@ M: object infer-call* 3 infer->r infer-call 3 infer-r> ; : infer-dip ( -- ) - commit-literals literals get [ \ dip def>> infer-quot-here ] [ pop 1 infer->r infer-quot-here 1 infer-r> ] if-empty ; : infer-2dip ( -- ) - commit-literals literals get [ \ 2dip def>> infer-quot-here ] [ pop 2 infer->r infer-quot-here 2 infer-r> ] if-empty ; : infer-3dip ( -- ) - commit-literals literals get [ \ 3dip def>> infer-quot-here ] [ pop 3 infer->r infer-quot-here 3 infer-r> ] From 03dd5db902072ef3046367b308f08a1f85621d29 Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Sat, 6 Dec 2008 14:24:44 -0600 Subject: [PATCH 2/7] Documentation update --- basis/concurrency/messaging/messaging-docs.factor | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/basis/concurrency/messaging/messaging-docs.factor b/basis/concurrency/messaging/messaging-docs.factor index 25538cd594..44ca6df269 100644 --- a/basis/concurrency/messaging/messaging-docs.factor +++ b/basis/concurrency/messaging/messaging-docs.factor @@ -74,9 +74,9 @@ ARTICLE: { "concurrency" "exceptions" } "Linked exceptions" "Exceptions are only raised in the parent when the parent does a " { $link receive } " or " { $link receive-if } ". This is because the exception is sent from the child to the parent as a message." ; ARTICLE: "concurrency.messaging" "Message-passing concurrency" -"The " { $vocab-link "concurrency.messaging" } " vocabulary is based upon the style of concurrency used in systems like Erlang and Termite. It is built on top of the standard Factor lightweight thread system." +"The " { $vocab-link "concurrency.messaging" } " vocabulary is based upon the style of concurrency used in systems like Erlang and Termite. It is built on top of " { $link "threads" } "." $nl -"A concurrency oriented program is one in which multiple threades run simultaneously in a single Factor image or across multiple running Factor instances. The threades can communicate with each other by asynchronous message sends." +"A concurrency-oriented program is one in which multiple threads run simultaneously in a single Factor image or across multiple running Factor instances. The threades can communicate with each other by asynchronous message sends." $nl "Although threades can share data via Factor's mutable data structures it is not recommended to mix shared state with message passing as it can lead to confusing code." { $subsection { "concurrency" "messaging" } } From b256539500e7830a66eb2597d66222893c59313b Mon Sep 17 00:00:00 2001 From: Eduardo Cavazos Date: Sat, 6 Dec 2008 15:03:02 -0600 Subject: [PATCH 3/7] ui.gadgets.sliders: Rewrite 'slider-scale' to not use shuffle words --- basis/ui/gadgets/sliders/sliders.factor | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/basis/ui/gadgets/sliders/sliders.factor b/basis/ui/gadgets/sliders/sliders.factor index 9e13e5ad7c..1c2055156e 100644 --- a/basis/ui/gadgets/sliders/sliders.factor +++ b/basis/ui/gadgets/sliders/sliders.factor @@ -36,8 +36,9 @@ TUPLE: slider < frame elevator thumb saved line ; #! A scaling factor such that if x is a slider co-ordinate, #! x*n is the screen position of the thumb, and conversely #! for x/n. The '1 max' calls avoid division by zero. - dup elevator-length over thumb-dim - 1 max - swap slider-max* 1 max / ; + [ [ elevator-length ] [ thumb-dim ] bi - 1 max ] + [ slider-max* 1 max ] + bi / ; : slider>screen ( m scale -- n ) slider-scale * ; : screen>slider ( m scale -- n ) slider-scale / ; From ebf0f27773caf065b4b78837b852fe81084de5bc Mon Sep 17 00:00:00 2001 From: Eduardo Cavazos Date: Sat, 6 Dec 2008 15:12:59 -0600 Subject: [PATCH 4/7] concurrency.messaging-docs: Use consistent spelling for 'threads'. --- basis/concurrency/messaging/messaging-docs.factor | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/basis/concurrency/messaging/messaging-docs.factor b/basis/concurrency/messaging/messaging-docs.factor index 44ca6df269..3bd2d330c3 100644 --- a/basis/concurrency/messaging/messaging-docs.factor +++ b/basis/concurrency/messaging/messaging-docs.factor @@ -8,20 +8,20 @@ HELP: send { $values { "message" object } { "thread" thread } } -{ $description "Send the message to the thread by placing it in the threades mailbox. This is an asynchronous operation and will return immediately. The receving thread will act on the message the next time it retrieves that item from its mailbox (usually using the " { $link receive } " word. The message can be any Factor object. For destinations that are instances of remote-thread the message must be a serializable Factor type." } +{ $description "Send the message to the thread by placing it in the threads mailbox. This is an asynchronous operation and will return immediately. The receving thread will act on the message the next time it retrieves that item from its mailbox (usually using the " { $link receive } " word. The message can be any Factor object. For destinations that are instances of remote-thread the message must be a serializable Factor type." } { $see-also receive receive-if } ; HELP: receive { $values { "message" object } } -{ $description "Return a message from the current threades mailbox. If the box is empty, suspend the thread until another thread places an item in the mailbox (usually via the " { $link send } " word." } +{ $description "Return a message from the current threads mailbox. If the box is empty, suspend the thread until another thread places an item in the mailbox (usually via the " { $link send } " word." } { $see-also send receive-if } ; HELP: receive-if { $values { "pred" "a predicate with stack effect " { $snippet "( obj -- ? )" } } { "message" object } } -{ $description "Return the first message from the current threades mailbox that satisfies the predicate. To satisfy the predicate, " { $snippet "pred" } " is called with the item on the stack and the predicate should leave a boolean indicating whether it was satisfied or not. If nothing in the mailbox satisfies the predicate then the thread will block until something does." } +{ $description "Return the first message from the current threads mailbox that satisfies the predicate. To satisfy the predicate, " { $snippet "pred" } " is called with the item on the stack and the predicate should leave a boolean indicating whether it was satisfied or not. If nothing in the mailbox satisfies the predicate then the thread will block until something does." } { $see-also send receive } ; HELP: spawn-linked @@ -29,7 +29,7 @@ HELP: spawn-linked { "name" string } { "thread" thread } } -{ $description "Start a thread which runs the given quotation. If that quotation throws an error which is not caught then the error will get propagated to the thread that spawned it. This can be used to set up 'supervisor' threades that restart child threades that crash due to uncaught errors.\n" } +{ $description "Start a thread which runs the given quotation. If that quotation throws an error which is not caught then the error will get propagated to the thread that spawned it. This can be used to set up 'supervisor' threads that restart child threads that crash due to uncaught errors.\n" } { $see-also spawn } ; ARTICLE: { "concurrency" "messaging" } "Sending and receiving messages" @@ -64,7 +64,7 @@ ARTICLE: { "concurrency" "synchronous-sends" } "Synchronous sends" ARTICLE: { "concurrency" "exceptions" } "Linked exceptions" "A thread can handle exceptions using the standard Factor exception handling mechanism. If an exception is uncaught the thread will terminate. For example:" { $code "[ 1 0 / \"This will not print\" print ] \"division-by-zero\" spawn" } -"Processes can be linked so that a parent thread can receive the exception that caused the child thread to terminate. In this way 'supervisor' threades can be created that are notified when child threades terminate and possibly restart them." +"Processes can be linked so that a parent thread can receive the exception that caused the child thread to terminate. In this way 'supervisor' threads can be created that are notified when child threads terminate and possibly restart them." { $subsection spawn-linked } "This will create a unidirectional link, such that if an uncaught exception causes the child to terminate, the parent thread can catch it:" { $code "[" @@ -76,9 +76,9 @@ ARTICLE: { "concurrency" "exceptions" } "Linked exceptions" ARTICLE: "concurrency.messaging" "Message-passing concurrency" "The " { $vocab-link "concurrency.messaging" } " vocabulary is based upon the style of concurrency used in systems like Erlang and Termite. It is built on top of " { $link "threads" } "." $nl -"A concurrency-oriented program is one in which multiple threads run simultaneously in a single Factor image or across multiple running Factor instances. The threades can communicate with each other by asynchronous message sends." +"A concurrency-oriented program is one in which multiple threads run simultaneously in a single Factor image or across multiple running Factor instances. The threads can communicate with each other by asynchronous message sends." $nl -"Although threades can share data via Factor's mutable data structures it is not recommended to mix shared state with message passing as it can lead to confusing code." +"Although threads can share data via Factor's mutable data structures it is not recommended to mix shared state with message passing as it can lead to confusing code." { $subsection { "concurrency" "messaging" } } { $subsection { "concurrency" "synchronous-sends" } } { $subsection { "concurrency" "exceptions" } } ; From d2ce4355f8bfd5e055688d2bc5c22d105221bc3b Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Sat, 6 Dec 2008 15:30:40 -0600 Subject: [PATCH 5/7] Fixing PPC backend --- basis/cpu/ppc/ppc.factor | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/basis/cpu/ppc/ppc.factor b/basis/cpu/ppc/ppc.factor index 46986dc5e6..c555c4b809 100644 --- a/basis/cpu/ppc/ppc.factor +++ b/basis/cpu/ppc/ppc.factor @@ -37,8 +37,8 @@ M: ppc %load-immediate ( reg n -- ) swap LOAD ; M: ppc %load-indirect ( reg obj -- ) [ 0 swap LOAD32 ] [ rc-absolute-ppc-2/2 rel-immediate ] bi* ; -: %load-dlsym ( symbol dll register -- ) - 0 swap LOAD32 rc-absolute-ppc-2/2 rel-dlsym ; +M: ppc %alien-global ( register symbol dll -- ) + [ 0 swap LOAD32 ] 2dip rc-absolute-ppc-2/2 rel-dlsym ; : ds-reg 29 ; inline : rs-reg 30 ; inline @@ -145,8 +145,8 @@ M:: ppc %string-nth ( dst src index temp -- ) temp temp index ADD temp temp index ADD temp temp byte-array-offset LHZ - temp temp 8 SLWI - dst dst temp OR + temp temp 7 SLWI + dst dst temp XOR "end" resolve-label ] with-scope ; @@ -172,7 +172,7 @@ M: ppc %sar-imm SRAWI ; M: ppc %not NOT ; : %alien-invoke-tail ( func dll -- ) - scratch-reg %load-dlsym scratch-reg MTCTR BCTR ; + [ scratch-reg ] 2dip %alien-global scratch-reg MTCTR BCTR ; :: exchange-regs ( r1 r2 -- ) scratch-reg r1 MR @@ -411,7 +411,7 @@ M: ppc %set-alien-float swap 0 STFS ; M: ppc %set-alien-double swap 0 STFD ; : load-zone-ptr ( reg -- ) - [ "nursery" f ] dip %load-dlsym ; + "nursery" f %alien-global ; : load-allot-ptr ( nursery-ptr allot-ptr -- ) [ drop load-zone-ptr ] [ swap 4 LWZ ] 2bi ; @@ -433,14 +433,11 @@ M:: ppc %allot ( dst size class nursery-ptr -- ) dst class store-header dst class store-tagged ; -: %alien-global ( dst name -- ) - [ f rot %load-dlsym ] [ drop dup 0 LWZ ] 2bi ; - : load-cards-offset ( dst -- ) - "cards_offset" %alien-global ; + [ "cards_offset" f %alien-global ] [ dup 0 LWZ ] bi ; : load-decks-offset ( dst -- ) - "decks_offset" %alien-global ; + [ "decks_offset" f %alien-global ] [ dup 0 LWZ ] bi ; M:: ppc %write-barrier ( src card# table -- ) card-mark scratch-reg LI @@ -627,14 +624,14 @@ M: ppc %prepare-alien-invoke #! Save Factor stack pointers in case the C code calls a #! callback which does a GC, which must reliably trace #! all roots. - "stack_chain" f scratch-reg %load-dlsym + scratch-reg "stack_chain" f %alien-global scratch-reg scratch-reg 0 LWZ 1 scratch-reg 0 STW ds-reg scratch-reg 8 STW rs-reg scratch-reg 12 STW ; M: ppc %alien-invoke ( symbol dll -- ) - 11 %load-dlsym 11 MTLR BLRL ; + [ 11 ] 2dip %alien-global 11 MTLR BLRL ; M: ppc %alien-callback ( quot -- ) 3 swap %load-indirect "c_to_factor" f %alien-invoke ; From 8a8f0c925c80907199c56a7aab60fea75ff18a59 Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Sat, 6 Dec 2008 15:31:17 -0600 Subject: [PATCH 6/7] Use BSR instruction to implement fixnum-log2 intrinsic --- basis/compiler/cfg/hats/hats.factor | 1 + basis/compiler/cfg/instructions/instructions.factor | 1 + basis/compiler/cfg/intrinsics/fixnum/fixnum.factor | 3 +++ basis/compiler/cfg/intrinsics/intrinsics.factor | 5 +++++ basis/compiler/codegen/codegen.factor | 1 + basis/cpu/architecture/architecture.factor | 1 + basis/cpu/x86/assembler/assembler.factor | 2 ++ basis/cpu/x86/x86.factor | 7 +++++-- core/math/integers/integers.factor | 10 ++++++---- core/math/math.factor | 11 +++-------- 10 files changed, 28 insertions(+), 14 deletions(-) diff --git a/basis/compiler/cfg/hats/hats.factor b/basis/compiler/cfg/hats/hats.factor index ca793de1b7..c0d5bf79a6 100644 --- a/basis/compiler/cfg/hats/hats.factor +++ b/basis/compiler/cfg/hats/hats.factor @@ -39,6 +39,7 @@ IN: compiler.cfg.hats : ^^shr-imm ( src1 src2 -- dst ) ^^i2 ##shr-imm ; inline : ^^sar-imm ( src1 src2 -- dst ) ^^i2 ##sar-imm ; inline : ^^not ( src -- dst ) ^^i1 ##not ; inline +: ^^log2 ( src -- dst ) ^^i1 ##log2 ; inline : ^^bignum>integer ( src -- dst ) ^^i1 i ##bignum>integer ; inline : ^^integer>bignum ( src -- dst ) ^^i1 i ##integer>bignum ; inline : ^^add-float ( src1 src2 -- dst ) ^^d2 ##add-float ; inline diff --git a/basis/compiler/cfg/instructions/instructions.factor b/basis/compiler/cfg/instructions/instructions.factor index b34e5f8232..5619a70740 100644 --- a/basis/compiler/cfg/instructions/instructions.factor +++ b/basis/compiler/cfg/instructions/instructions.factor @@ -92,6 +92,7 @@ INSN: ##shl-imm < ##binary-imm ; INSN: ##shr-imm < ##binary-imm ; INSN: ##sar-imm < ##binary-imm ; INSN: ##not < ##unary ; +INSN: ##log2 < ##unary ; ! Overflowing arithmetic TUPLE: ##fixnum-overflow < insn src1 src2 ; diff --git a/basis/compiler/cfg/intrinsics/fixnum/fixnum.factor b/basis/compiler/cfg/intrinsics/fixnum/fixnum.factor index 69cd5e5669..3ad716d847 100644 --- a/basis/compiler/cfg/intrinsics/fixnum/fixnum.factor +++ b/basis/compiler/cfg/intrinsics/fixnum/fixnum.factor @@ -53,6 +53,9 @@ IN: compiler.cfg.intrinsics.fixnum : emit-fixnum-bitnot ( -- ) ds-pop ^^not tag-mask get ^^xor-imm ds-push ; +: emit-fixnum-log2 ( -- ) + ds-pop ^^log2 tag-bits get ^^sub-imm ^^tag-fixnum ds-push ; + : (emit-fixnum*fast) ( -- dst ) 2inputs ^^untag-fixnum ^^mul ; diff --git a/basis/compiler/cfg/intrinsics/intrinsics.factor b/basis/compiler/cfg/intrinsics/intrinsics.factor index 41f4bf47a5..6656cd11f7 100644 --- a/basis/compiler/cfg/intrinsics/intrinsics.factor +++ b/basis/compiler/cfg/intrinsics/intrinsics.factor @@ -19,6 +19,7 @@ QUALIFIED: slots.private QUALIFIED: strings.private QUALIFIED: classes.tuple.private QUALIFIED: math.private +QUALIFIED: math.integers.private QUALIFIED: alien.accessors IN: compiler.cfg.intrinsics @@ -93,6 +94,9 @@ IN: compiler.cfg.intrinsics alien.accessors:set-alien-double } [ t "intrinsic" set-word-prop ] each ; +: enable-fixnum-log2 ( -- ) + \ math.integers.private:fixnum-log2 t "intrinsic" set-word-prop ; + : emit-intrinsic ( node word -- node/f ) { { \ kernel.private:tag [ drop emit-tag iterate-next ] } @@ -108,6 +112,7 @@ IN: compiler.cfg.intrinsics { \ math.private:fixnum-bitxor [ [ ^^xor ] [ ^^xor-imm ] emit-fixnum-op iterate-next ] } { \ math.private:fixnum-shift-fast [ emit-fixnum-shift-fast iterate-next ] } { \ math.private:fixnum-bitnot [ drop emit-fixnum-bitnot iterate-next ] } + { \ math.integers.private:fixnum-log2 [ drop emit-fixnum-log2 iterate-next ] } { \ math.private:fixnum*fast [ emit-fixnum*fast iterate-next ] } { \ math.private:fixnum< [ cc< emit-fixnum-comparison iterate-next ] } { \ math.private:fixnum<= [ cc<= emit-fixnum-comparison iterate-next ] } diff --git a/basis/compiler/codegen/codegen.factor b/basis/compiler/codegen/codegen.factor index fe3da93130..9f134c02d7 100644 --- a/basis/compiler/codegen/codegen.factor +++ b/basis/compiler/codegen/codegen.factor @@ -163,6 +163,7 @@ M: ##shl-imm generate-insn dst/src1/src2 %shl-imm ; M: ##shr-imm generate-insn dst/src1/src2 %shr-imm ; M: ##sar-imm generate-insn dst/src1/src2 %sar-imm ; M: ##not generate-insn dst/src %not ; +M: ##log2 generate-insn dst/src %log2 ; : src1/src2 ( insn -- src1 src2 ) [ src1>> register ] [ src2>> register ] bi ; inline diff --git a/basis/cpu/architecture/architecture.factor b/basis/cpu/architecture/architecture.factor index 836385574d..c609b9e98d 100644 --- a/basis/cpu/architecture/architecture.factor +++ b/basis/cpu/architecture/architecture.factor @@ -77,6 +77,7 @@ HOOK: %shl-imm cpu ( dst src1 src2 -- ) HOOK: %shr-imm cpu ( dst src1 src2 -- ) HOOK: %sar-imm cpu ( dst src1 src2 -- ) HOOK: %not cpu ( dst src -- ) +HOOK: %log2 cpu ( dst src -- ) HOOK: %fixnum-add cpu ( src1 src2 -- ) HOOK: %fixnum-add-tail cpu ( src1 src2 -- ) diff --git a/basis/cpu/x86/assembler/assembler.factor b/basis/cpu/x86/assembler/assembler.factor index 27c00cb3c0..2bea887295 100644 --- a/basis/cpu/x86/assembler/assembler.factor +++ b/basis/cpu/x86/assembler/assembler.factor @@ -384,6 +384,8 @@ M: operand CMP OCT: 070 2-operand ; : XCHG ( dst src -- ) OCT: 207 2-operand ; +: BSR ( dst src -- ) swap { HEX: 0f HEX: bd } (2-operand) ; + : NOT ( dst -- ) { BIN: 010 t HEX: f7 } 1-operand ; : NEG ( dst -- ) { BIN: 011 t HEX: f7 } 1-operand ; : MUL ( dst -- ) { BIN: 100 t HEX: f7 } 1-operand ; diff --git a/basis/cpu/x86/x86.factor b/basis/cpu/x86/x86.factor index c477e98aa7..44300a75f9 100644 --- a/basis/cpu/x86/x86.factor +++ b/basis/cpu/x86/x86.factor @@ -5,10 +5,12 @@ cpu.x86.assembler cpu.x86.assembler.private cpu.architecture kernel kernel.private math memory namespaces make sequences words system layouts combinators math.order fry locals compiler.constants compiler.cfg.registers -compiler.cfg.instructions compiler.codegen -compiler.codegen.fixup ; +compiler.cfg.instructions compiler.cfg.intrinsics +compiler.codegen compiler.codegen.fixup ; IN: cpu.x86 +<< enable-fixnum-log2 >> + M: x86 two-operand? t ; HOOK: temp-reg-1 cpu ( -- reg ) @@ -92,6 +94,7 @@ M: x86 %shl-imm nip SHL ; M: x86 %shr-imm nip SHR ; M: x86 %sar-imm nip SAR ; M: x86 %not drop NOT ; +M: x86 %log2 BSR ; : ?MOV ( dst src -- ) 2dup = [ 2drop ] [ MOV ] if ; inline diff --git a/core/math/integers/integers.factor b/core/math/integers/integers.factor index fcb1b65d80..910d394c55 100644 --- a/core/math/integers/integers.factor +++ b/core/math/integers/integers.factor @@ -40,11 +40,13 @@ M: fixnum bitnot fixnum-bitnot ; M: fixnum bit? neg shift 1 bitand 0 > ; -: (fixnum-log2) ( accum n -- accum ) - dup 1 number= [ drop ] [ [ 1+ ] [ 2/ ] bi* (fixnum-log2) ] if ; - inline recursive +: fixnum-log2 ( x -- n ) + 0 swap [ dup 1 number= not ] [ [ 1+ ] [ 2/ ] bi* ] [ ] while drop ; -M: fixnum (log2) 0 swap (fixnum-log2) ; +M: fixnum (log2) fixnum-log2 ; + +M: integer next-power-of-2 + dup 2 <= [ drop 2 ] [ 1- log2 1+ 2^ ] if ; M: bignum >fixnum bignum>fixnum ; M: bignum >bignum ; diff --git a/core/math/math.factor b/core/math/math.factor index 5c53d99cff..8b064725d3 100644 --- a/core/math/math.factor +++ b/core/math/math.factor @@ -53,7 +53,7 @@ PRIVATE> "log2 expects positive inputs" throw ] [ (log2) - ] if ; foldable + ] if ; inline : zero? ( x -- ? ) 0 number= ; inline : 1+ ( x -- y ) 1 + ; inline @@ -103,14 +103,9 @@ M: float fp-infinity? ( float -- ? ) drop f ] if ; -: (next-power-of-2) ( i n -- n ) - 2dup >= [ - drop - ] [ - [ 1 shift ] dip (next-power-of-2) - ] if ; +GENERIC: next-power-of-2 ( m -- n ) foldable -: next-power-of-2 ( m -- n ) 2 swap (next-power-of-2) ; foldable +M: real next-power-of-2 1+ >integer next-power-of-2 ; : power-of-2? ( n -- ? ) dup 0 <= [ drop f ] [ dup 1- bitand zero? ] if ; foldable From bac338663da5965245c686e10537a97b76d9b38c Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Sat, 6 Dec 2008 15:31:35 -0600 Subject: [PATCH 7/7] Mark a word inline --- core/hashtables/hashtables.factor | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/core/hashtables/hashtables.factor b/core/hashtables/hashtables.factor index a52ac65d18..8663f25a70 100644 --- a/core/hashtables/hashtables.factor +++ b/core/hashtables/hashtables.factor @@ -40,7 +40,7 @@ TUPLE: hashtable 0 >>count 0 >>deleted drop ; inline : reset-hash ( n hash -- ) - swap >>array init-hash ; + swap >>array init-hash ; inline : (new-key@) ( key keys i -- keys n empty? ) 3dup swap array-nth dup ((empty)) eq? [