classes: use check-instance in a few places, to remove duplication.

basis/core-text/core-text.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors alien.c-types alien.data alien.syntax arrays
-assocs cache colors combinators core-foundation
+assocs cache classes colors combinators core-foundation
 core-foundation.attributed-strings core-foundation.strings
 core-graphics core-graphics.types core-text.fonts destructors
 fonts init kernel locals make math math.functions math.order
@@ -34,8 +34,6 @@ FUNCTION: CGRect CTLineGetImageBounds ( CTLineRef line, CGContextRef context )
 
 SYMBOL: retina?
 
-ERROR: not-a-string object ;
-
 MEMO: make-attributes ( open-font color -- hashtable )
     [
         kCTForegroundColorAttributeName ,,
@@ -46,7 +44,7 @@ MEMO: make-attributes ( open-font color -- hashtable )
     [
         [
             dup selection? [ string>> ] when
-            dup string? [ not-a-string ] unless
+            string check-instance
         ] 2dip
         make-attributes <CFAttributedString> &CFRelease
         CTLineCreateWithAttributedString

basis/debugger/debugger.factor

@@ -215,9 +215,6 @@ M: inconsistent-next-method summary
 M: check-method-error summary
     drop "Invalid parameters for create-method" ;
 
-M: not-a-tuple summary
-    drop "Not a tuple" ;
-
 M: bad-superclass summary
     drop "Tuple classes can only inherit from non-final tuple classes" ;
 
@@ -372,8 +369,6 @@ M: bad-escape error.
 
 M: bad-literal-tuple summary drop "Bad literal tuple" ;
 
-M: not-a-mixin-class summary drop "Not a mixin class" ;
-
 M: not-found-in-roots summary
     path>> "Cannot resolve vocab: " prepend ;
 

basis/delegate/delegate.factor

@@ -1,10 +1,10 @@
 ! Copyright (C) 2007, 2008 Daniel Ehrenberg
 ! Portions copyright (C) 2009, 2010 Slava Pestov, Joe Groff
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays assocs classes.tuple definitions effects generic
+USING: accessors arrays assocs classes classes.tuple
-generic.standard hashtables kernel lexer math parser
+compiler.units definitions effects fry generic generic.standard
-generic.parser sequences sets slots words words.symbol fry
+hashtables kernel lexer make math parser sequences sets slots
-compiler.units make ;
+words words.symbol ;
 IN: delegate
 
 ERROR: broadcast-words-must-have-no-outputs group ;
@@ -159,11 +159,8 @@ M: consultation forget*
 : show-words ( wordlist' -- wordlist )
     [ dup second zero? [ first ] when ] map ;
 
-ERROR: not-a-generic word ;
-
 : check-generic ( generic -- )
-    dup array? [ first ] when
+    dup array? [ first ] when generic check-instance drop ;
-    dup generic? [ drop ] [ not-a-generic ] if ;
 
 PRIVATE>
 

basis/interval-maps/interval-maps.factor

@@ -1,7 +1,8 @@
 ! Copyright (C) 2008 Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays assocs binary-search grouping kernel
+USING: accessors arrays assocs binary-search classes grouping
-locals make math math.order sequences sequences.private sorting ;
+kernel locals make math math.order sequences sequences.private
+sorting ;
 IN: interval-maps
 
 ! Intervals are triples of { start end value }
@@ -28,15 +29,10 @@ TUPLE: interval-map { array array read-only } ;
 : >intervals ( specification -- intervals )
     [ suffix ] { } assoc>map concat 3 group ;
 
-ERROR: not-an-interval-map obj ;
-
-: check-interval-map ( map -- map )
-    dup interval-map? [ not-an-interval-map ] unless ; inline
-
 PRIVATE>
 
 : interval-at* ( key map -- value ? )
-    check-interval-map
+    interval-map check-instance
     [ drop ] [ find-interval ] 2bi
     [ nip ] [ interval-contains? ] 2bi
     [ third-unsafe t ] [ drop f f ] if ; inline
@@ -46,7 +42,7 @@ PRIVATE>
 : interval-key? ( key map -- ? ) interval-at* nip ; inline
 
 : interval-values ( map -- values )
-    check-interval-map array>> [ third-unsafe ] map ;
+    interval-map check-instance array>> [ third-unsafe ] map ;
 
 : <interval-map> ( specification -- map )
     all-intervals [ first-unsafe second-unsafe ] sort-with

basis/interval-sets/interval-sets.factor

@@ -1,8 +1,9 @@
 ! Copyright (C) 2009 Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors alien.c-types arrays assocs binary-search
-combinators fry grouping kernel locals make math math.order
+classes combinators fry grouping kernel locals make math
-sequences sequences.private sorting specialized-arrays ;
+math.order sequences sequences.private sorting
+specialized-arrays ;
 SPECIALIZED-ARRAY: uint
 IN: interval-sets
 ! Sets of positive integers
@@ -10,17 +11,8 @@ IN: interval-sets
 ! Intervals are a pair of { start end }
 TUPLE: interval-set { array uint-array read-only } ;
 
-<PRIVATE
-
-ERROR: not-an-interval-set obj ;
-
-: check-interval-set ( map -- map )
-    dup interval-set? [ not-an-interval-set ] unless ; inline
-
-PRIVATE>
-
 : in? ( key set -- ? )
-    check-interval-set array>>
+    interval-set check-instance array>>
     dupd [ <=> ] with search swap [
         even? [ >= ] [ 1 - <= ] if
     ] [ 2drop f ] if* ;

basis/io/backend/unix/unix.factor

@@ -1,6 +1,6 @@
 ! Copyright (C) 2004, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors alien.c-types alien.data alien.syntax
+USING: accessors alien.c-types alien.data alien.syntax classes
 classes.struct combinators destructors destructors.private fry
 io.backend io.backend.unix.multiplexers io.buffers io.files
 io.ports io.timeouts kernel kernel.private libc locals make math
@@ -83,13 +83,8 @@ M: unix wait-for-fd ( handle event -- )
 
 ! Some general stuff
 
-ERROR: not-a-buffered-port port ;
-
-: check-buffered-port ( port -- port )
-    dup buffered-port? [ not-a-buffered-port ] unless ; inline
-
 M: fd refill
-    [ check-buffered-port buffer>> ] [ fd>> ] bi*
+    [ buffered-port check-instance buffer>> ] [ fd>> ] bi*
     over [ buffer-end ] [ buffer-capacity ] bi read
     { fixnum } declare dup 0 >= [
         swap buffer+ f
@@ -108,7 +103,7 @@ M: unix (wait-to-read) ( port -- )
 
 ! Writers
 M: fd drain
-    [ check-buffered-port buffer>> ] [ fd>> ] bi*
+    [ buffered-port check-instance buffer>> ] [ fd>> ] bi*
     over [ buffer@ ] [ buffer-length ] bi write
     { fixnum } declare dup 0 >= [
         over buffer-consume

basis/io/ports/ports.factor

@@ -1,6 +1,6 @@
 ! Copyright (C) 2005, 2010 Slava Pestov, Doug Coleman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors alien combinators destructors hints io
+USING: accessors alien classes combinators destructors hints io
 io.backend io.buffers io.encodings io.files io.timeouts kernel
 kernel.private libc locals math math.order math.private
 namespaces sequences strings system ;
@@ -42,11 +42,6 @@ M: input-port stream-read1
     check-disposed
     dup wait-to-read [ drop f ] [ buffer>> buffer-pop ] if ; inline
 
-ERROR: not-a-c-ptr object ;
-
-: check-c-ptr ( c-ptr -- c-ptr )
-    dup c-ptr? [ not-a-c-ptr ] unless ; inline
-
 <PRIVATE
 
 : read-step ( count port -- count ptr/f )
@@ -73,11 +68,11 @@ ERROR: not-a-c-ptr object ;
 PRIVATE>
 
 M: input-port stream-read-partial-unsafe
-    [ check-c-ptr swap ] dip prepare-read read-step
+    [ c-ptr check-instance swap ] dip prepare-read read-step
     [ swap [ memcpy ] keep ] [ 2drop 0 ] if* ;
 
 M: input-port stream-read-unsafe
-    [ check-c-ptr swap ] dip prepare-read 0 read-loop ;
+    [ c-ptr check-instance swap ] dip prepare-read 0 read-loop ;
 
 <PRIVATE
 
@@ -158,7 +153,7 @@ PRIVATE>
 M: output-port stream-write
     check-disposed [
         binary-object
-        [ check-c-ptr ] [ integer>fixnum-strict ] bi*
+        [ c-ptr check-instance ] [ integer>fixnum-strict ] bi*
     ] [ port-write ] bi* ;
 
 HOOK: tell-handle os ( handle -- n )

basis/tuple-arrays/tuple-arrays-tests.factor

@@ -33,7 +33,7 @@ TUPLE-ARRAY: broken
 
 ! Can't define a tuple array for a non-tuple class
 [ "IN: tuple-arrays.tests USING: tuple-arrays words ; TUPLE-ARRAY: word" eval( -- ) ]
-[ error>> not-a-tuple? ]
+[ error>> not-an-instance? ]
 must-fail-with
 
 ! Can't define a tuple array for a non-final class

basis/tuple-arrays/tuple-arrays.factor

@@ -26,11 +26,9 @@ MACRO: write-tuple ( class -- quot )
     bi '[ _ dip @ ] ;
 
 : check-final ( class -- )
-    {
+    tuple-class check-instance
-        { [ dup tuple-class? not ] [ not-a-tuple ] }
+    final-class check-instance
-        { [ dup final-class? not ] [ not-final ] }
+    drop ;
-        [ drop ]
-    } cond ;
 
 PRIVATE>
 

basis/ui/gadgets/labels/labels.factor

@@ -1,9 +1,10 @@
 ! Copyright (C) 2005, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays colors.constants combinators fonts fry
+USING: accessors arrays classes colors.constants combinators
-kernel make math.functions models namespaces sequences splitting
+fonts fry kernel make math.functions models namespaces sequences
-strings ui.baseline-alignment ui.gadgets ui.gadgets.tracks
+splitting strings ui.baseline-alignment ui.gadgets
-ui.pens.solid ui.render ui.text ui.theme.images ;
+ui.gadgets.tracks ui.pens.solid ui.render ui.text
+ui.theme.images ;
 IN: ui.gadgets.labels
 
 ! A label gadget draws a string.
@@ -23,15 +24,11 @@ PRIVATE>
 : ?string-lines ( string -- string/array )
     CHAR: \n over member-eq? [ string-lines ] when ;
 
-ERROR: not-a-string object ;
-
 M: label string<< ( string label -- )
     [
-        {
+        dup string-array? [
-            { [ dup string-array? ] [ ] }
+            string check-instance ?string-lines
-            { [ dup string? ] [ ?string-lines ] }
+        ] unless
-            [ not-a-string ]
-        } cond
     ] dip [ text<< ] [ relayout ] bi ; inline
 
 : label-theme ( gadget -- gadget )

core/classes/algebra/algebra.factor

@@ -13,21 +13,10 @@ TUPLE: anonymous-union { members read-only } ;
 
 INSTANCE: anonymous-union classoid
 
-ERROR: not-classoids sequence ;
-
-: check-classoids ( members -- members )
-    dup [ classoid? ] all?
-    [ [ classoid? ] reject not-classoids ] unless ;
-
-ERROR: not-a-classoid object ;
-
-: check-classoid ( object -- object )
-    dup classoid? [ not-a-classoid ] unless ;
-
 : <anonymous-union> ( members -- classoid )
-    check-classoids
+    [ classoid check-instance ] map [ null eq? ] reject
-    [ null eq? ] reject members
+    members dup length 1 =
-    dup length 1 = [ first ] [ sort-classes f like anonymous-union boa ] if ;
+    [ first ] [ sort-classes f like anonymous-union boa ] if ;
 
 M: anonymous-union rank-class drop 6 ;
 
@@ -36,7 +25,7 @@ TUPLE: anonymous-intersection { participants read-only } ;
 INSTANCE: anonymous-intersection classoid
 
 : <anonymous-intersection> ( participants -- classoid )
-    check-classoids
+    [ classoid check-instance ] map
     members dup length 1 =
     [ first ] [ sort-classes f like anonymous-intersection boa ] if ;
 
@@ -47,7 +36,7 @@ TUPLE: anonymous-complement { class read-only } ;
 INSTANCE: anonymous-complement classoid
 
 : <anonymous-complement> ( object -- classoid )
-    check-classoid anonymous-complement boa ;
+    classoid check-instance anonymous-complement boa ;
 
 M: anonymous-complement rank-class drop 3 ;
 

core/classes/builtin/builtin.factor

@@ -9,11 +9,6 @@ SYMBOL: builtins
 PREDICATE: builtin-class < class
     "metaclass" word-prop builtin-class eq? ;
 
-ERROR: not-a-builtin object ;
-
-: check-builtin ( class -- )
-    dup builtin-class? [ drop ] [ not-a-builtin ] if ;
-
 : class>type ( class -- n ) "type" word-prop ; foldable
 
 : type>class ( n -- class ) builtins get-global nth ; foldable

core/classes/maybe/maybe-tests.factor

@@ -63,4 +63,4 @@ M: f lol2 drop "lol22" ;
 [ 3 lol2 ] [ no-method? ] must-fail-with
 
 [ "IN: classes-tests maybe{ 1 2 3 }" eval( -- ) ]
-[ error>> not-classoids? ] must-fail-with
+[ error>> not-an-instance? ] must-fail-with

core/classes/mixin/mixin-tests.factor

@@ -125,7 +125,7 @@ SYMBOL: a-symbol
     [
         \ a-symbol \ silly-mixin add-mixin-instance
     ] with-compilation-unit
-] [ not-a-class? ] must-fail-with
+] [ not-an-instance? ] must-fail-with
 
 SYMBOL: not-a-mixin
 TUPLE: a-class ;
@@ -134,7 +134,7 @@ TUPLE: a-class ;
     [
         \ a-class \ not-a-mixin add-mixin-instance
     ] with-compilation-unit
-] [ not-a-mixin-class? ] must-fail-with
+] [ not-an-instance? ] must-fail-with
 
 ! Changing a mixin member's metaclass should not remove it from the mixin
 MIXIN: metaclass-change-mixin

core/classes/mixin/mixin.factor

@@ -61,13 +61,8 @@ M: mixin-class rank-class drop 8 ;
 
 PRIVATE>
 
-ERROR: not-a-class object ;
-
-ERROR: not-a-mixin-class object ;
-
 : check-types ( class mixin -- class mixin )
-    [ dup class? [ not-a-class ] unless ]
+    [ class check-instance ] [ mixin-class check-instance ] bi* ;
-    [ dup mixin-class? [ not-a-mixin-class ] unless ] bi* ;
 
 : add-mixin-instance ( class mixin -- )
     check-types [ 2drop ] [ (add-mixin-instance) ] if-mixin-member? ;

core/classes/tuple/tuple-docs.factor

@@ -390,11 +390,6 @@ HELP: define-tuple-slots
 { $description "Defines slot accessor and mutator words for the tuple." }
 $low-level-note ;
 
-HELP: check-tuple
-{ $values { "class" class } }
-{ $description "Throws a " { $link check-tuple } " error if " { $snippet "word" } " is not a tuple class word." }
-{ $error-description "Thrown if " { $link POSTPONE: C: } " is called with a word which does not name a tuple class." } ;
-
 HELP: define-tuple-class
 { $values { "class" word } { "superclass" class } { "slots" { $sequence string } } }
 { $description "Defines a tuple class inheriting from " { $snippet "superclass" } " with slots named by " { $snippet "slots" } ". This is the run time equivalent of " { $link POSTPONE: TUPLE: } "." }

core/classes/tuple/tuple.factor

@@ -17,8 +17,6 @@ PREDICATE: tuple-class < class
 
 ERROR: too-many-slots class slots got max ;
 
-ERROR: not-a-tuple object ;
-
 : all-slots ( class -- slots )
     superclasses-of [ "slots" word-prop ] map concat ;
 
@@ -59,14 +57,12 @@ M: tuple class-of layout-of 2 slot { word } declare ; inline
     layout-of 3 slot { fixnum } declare ; inline
 
 : layout-up-to-date? ( object -- ? )
-    dup tuple?
+    dup tuple? [
-    [ [ layout-of ] [ class-of tuple-layout ] bi eq? ] [ drop t ] if ;
+        [ layout-of ] [ class-of tuple-layout ] bi eq?
-
+    ] [ drop t ] if ;
-: check-tuple ( object -- tuple )
-    dup tuple? [ not-a-tuple ] unless ; inline
 
 : prepare-tuple-slots ( tuple -- n tuple )
-    check-tuple [ tuple-size <iota> ] keep ;
+    tuple check-instance [ tuple-size <iota> ] keep ;
 
 : copy-tuple-slots ( n tuple -- array )
     [ array-nth ] curry map ;
@@ -323,13 +319,9 @@ M: tuple-class (define-tuple-class)
 : boa-effect ( class -- effect )
     [ all-slots [ name>> ] map ] [ name>> 1array ] bi <effect> ;
 
-ERROR: not-a-tuple-class object ;
-
-: check-tuple-class ( class -- class )
-    dup tuple-class? [ not-a-tuple-class ] unless ; inline
-
 : define-boa-word ( word class -- )
-    check-tuple-class [ [ boa ] curry ] [ boa-effect ] bi
+    tuple-class check-instance
+    [ [ boa ] curry ] [ boa-effect ] bi
     define-inline ;
 
 : forget-slot-accessors ( class slots -- )

core/io/streams/sequence/sequence.factor

@@ -1,8 +1,8 @@
 ! Copyright (C) 2009 Daniel Ehrenberg
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors byte-arrays combinators destructors growable
+USING: accessors byte-arrays classes combinators destructors
-io io.private io.streams.plain kernel math math.order sequences
+growable io io.private io.streams.plain kernel math math.order
-sequences.private strings ;
+sequences sequences.private strings ;
 IN: io.streams.sequence
 
 ! Readers
@@ -29,21 +29,13 @@ SLOT: i
         [ [ dup pick + ] change-i underlying>> ] bi
     ] dip [ <sequence-copy> (copy) drop ] 3curry keep ; inline
 
-ERROR: not-a-byte-array obj ;
-: check-byte-array ( buf stream offset -- buf stream offset )
-    pick byte-array? [ pick not-a-byte-array ] unless ; inline
-
-ERROR: not-a-string obj ;
-: check-string ( buf stream offset -- buf stream offset )
-    pick string? [ pick not-a-string ] unless ; inline
-
 : (sequence-read-unsafe) ( n buf stream -- count )
     [ integer>fixnum ]
     [ dup slice? [ [ seq>> ] [ from>> ] bi ] [ 0 ] if ]
     [
         tuck stream-element-type +byte+ eq?
-        [ check-byte-array sequence-copy-unsafe ]
+        [ [ byte-array check-instance ] 2dip sequence-copy-unsafe ]
-        [ check-string sequence-copy-unsafe ] if
+        [ [ string check-instance ] 2dip sequence-copy-unsafe ] if
     ] tri* ; inline
 
 PRIVATE>

core/lexer/lexer.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2008, 2010 Slava Pestov, Joe Groff.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays combinators continuations io kernel
+USING: accessors arrays classes combinators continuations io
-kernel.private math math.parser namespaces sequences
+kernel kernel.private math math.parser namespaces sequences
 sequences.private source-files.errors strings vectors ;
 IN: lexer
 
@@ -15,13 +15,8 @@ TUPLE: lexer
 
 TUPLE: lexer-parsing-word word line line-text column ;
 
-ERROR: not-a-lexer object ;
-
-: check-lexer ( lexer -- lexer )
-    dup lexer? [ not-a-lexer ] unless ; inline
-
 : next-line ( lexer -- )
-    check-lexer
+    lexer check-instance
     dup [ line>> ] [ text>> ] bi ?nth "" or
     [ >>line-text ] [ length >>line-length ] bi
     [ 1 + ] change-line
@@ -29,13 +24,13 @@ ERROR: not-a-lexer object ;
     drop ;
 
 : push-parsing-word ( word -- )
-    lexer get check-lexer [
+    lexer get lexer check-instance [
         [ line>> ] [ line-text>> ] [ column>> ] tri
         lexer-parsing-word boa
     ] [ parsing-words>> push ] bi ;
 
 : pop-parsing-word ( -- )
-    lexer get check-lexer parsing-words>> pop* ;
+    lexer get lexer check-instance parsing-words>> pop* ;
 
 : new-lexer ( text class -- lexer )
     new
@@ -58,7 +53,7 @@ ERROR: unexpected want got ;
     ] dip or ; inline
 
 : change-lexer-column ( ..a lexer quot: ( ..a col line -- ..b newcol ) -- ..b )
-    [ check-lexer [ column>> ] [ line-text>> ] bi ] prepose
+    [ lexer check-instance [ column>> ] [ line-text>> ] bi ] prepose
     keep column<< ; inline
 
 GENERIC: skip-blank ( lexer -- )
@@ -89,13 +84,13 @@ M: lexer skip-word
     ] change-lexer-column ;
 
 : still-parsing? ( lexer -- ? )
-    check-lexer [ line>> ] [ text>> length ] bi <= ;
+    lexer check-instance [ line>> ] [ text>> length ] bi <= ;
 
 : still-parsing-line? ( lexer -- ? )
-    check-lexer [ column>> ] [ line-length>> ] bi < ;
+    lexer check-instance [ column>> ] [ line-length>> ] bi < ;
 
 : (parse-raw) ( lexer -- str )
-    check-lexer {
+    lexer check-instance {
         [ column>> ]
         [ skip-word ]
         [ column>> ]
@@ -159,6 +154,8 @@ M: lexer-error error-line [ error>> error-line ] [ line>> ] bi or ;
         } cleave
     ] dip lexer-error boa ;
 
+<PRIVATE
+
 : simple-lexer-dump ( error -- )
     [ line>> number>string ": " append ]
     [ line-text>> ]
@@ -166,24 +163,22 @@ M: lexer-error error-line [ error>> error-line ] [ line>> ] bi or ;
     pick length + CHAR: \s <string>
     [ write ] [ print ] [ write "^" print ] tri* ;
 
-: (parsing-word-lexer-dump) ( error parsing-word -- )
+: parsing-word-lexer-dump ( error parsing-word -- error )
+    2dup [ line>> ] same? [ drop ] [
         [
             line>> number>string
             over line>> number>string length
             CHAR: \s pad-head
             ": " append write
         ] [ line-text>> print ] bi
-    simple-lexer-dump ;
+    ] if ;
 
-: parsing-word-lexer-dump ( error parsing-word -- )
+PRIVATE>
-    2dup [ line>> ] same?
-    [ drop simple-lexer-dump ]
-    [ (parsing-word-lexer-dump) ] if ;
 
 : lexer-dump ( error -- )
-    dup parsing-words>>
+    dup parsing-words>> ?last [
-    [ simple-lexer-dump ]
+        parsing-word-lexer-dump
-    [ last parsing-word-lexer-dump ] if-empty ;
+    ] when* simple-lexer-dump ;
 
 : with-lexer ( lexer quot -- newquot )
     [ [ <lexer-error> rethrow ] recover ] curry

core/syntax/syntax.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2004, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays byte-arrays byte-vectors
-classes.algebra.private classes.builtin classes.error
+classes classes.algebra.private classes.builtin classes.error
 classes.intersection classes.maybe classes.mixin classes.parser
 classes.predicate classes.singleton classes.tuple classes.tuple.parser
 classes.union combinators compiler.units definitions effects
@@ -128,7 +128,8 @@ IN: bootstrap.syntax
     "BUILTIN:" [
         scan-word-name
         current-vocab lookup-word
-        (parse-tuple-definition) 2drop check-builtin
+        (parse-tuple-definition)
+        2drop builtin-class check-instance drop
     ] define-core-syntax
 
     "SYMBOL:" [

extra/euler/operators/operators.factor

@@ -29,10 +29,8 @@ ERROR: edges-in-same-face ;
     [ dup opposite-edge>> assert-same-face ]
     bi ;
 
-ERROR: not-a-base-face face ;
-
 : assert-base-face ( face -- )
-    dup base-face? [ drop ] [ not-a-base-face ] if ;
+    base-face check-instance drop ;
 
 ERROR: has-rings face ;
 

extra/math/matrices/laplace/laplace.factor

@@ -29,12 +29,7 @@ INSTANCE: missing immutable-sequence
         v* [ odd? [ neg ] when ] map-index sum
     ] if ;
 
-ERROR: not-a-square-matrix matrix ;
-
-: check-square-matrix ( matrix -- matrix )
-    dup square-matrix? [ not-a-square-matrix ] unless ; inline
-
 PRIVATE>
 
 : determinant ( matrix -- x )
-    check-square-matrix 0 swap laplace-expansion ;
+    square-matrix check-instance 0 swap laplace-expansion ;