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Add ncleave combinator to generalizations

db4
Slava Pestov 2008-12-09 04:20:20 -06:00
parent 1e1640abb3
commit 474b718337
2 changed files with 18 additions and 1 deletions
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15
basis/generalizations/generalizations-docs.factor
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@ -1,5 +1,5 @@
USING: help.syntax help.markup kernel sequences quotations USING: help.syntax help.markup kernel sequences quotations
math arrays ; math arrays combinators ;
IN: generalizations IN: generalizations
HELP: nsequence HELP: nsequence
@ -234,6 +234,18 @@ HELP: napply
} }
} ; } ;
HELP: ncleave
{ $values { "quots" "a sequence of quotations" } { "n" integer } }
{ $description "A generalization of " { $link cleave } " and " { $link 2cleave } " that can work for any quotation arity."
}
{ $examples
"Some core words expressed in terms of " { $link ncleave } ":"
{ $table
{ { $link cleave } { $snippet "1 ncleave" } }
{ { $link 2cleave } { $snippet "2 ncleave" } }
}
} ;
HELP: mnswap HELP: mnswap
{ $values { "m" integer } { "n" integer } } { $values { "m" integer } { "n" integer } }
{ $description "Swaps the top " { $snippet "m" } " stack elements with the " { $snippet "n" } " elements directly underneath." } { $description "Swaps the top " { $snippet "m" } " stack elements with the " { $snippet "n" } " elements directly underneath." }
@ -269,6 +281,7 @@ $nl
{ $subsection nslip } { $subsection nslip }
{ $subsection nkeep } { $subsection nkeep }
{ $subsection napply } { $subsection napply }
{ $subsection ncleave }
"Generalized quotation construction:" "Generalized quotation construction:"
{ $subsection ncurry } { $subsection ncurry }
{ $subsection nwith } ; { $subsection nwith } ;

4
basis/generalizations/generalizations.factor
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@ -69,6 +69,10 @@ MACRO: ncurry ( n -- )
MACRO: nwith ( n -- ) MACRO: nwith ( n -- )
[ with ] n*quot ; [ with ] n*quot ;
MACRO: ncleave ( quots n -- )
[ '[ _ '[ _ _ nkeep ] ] map [ ] join ] [ '[ _ ndrop ] ] bi
compose ;
MACRO: napply ( n -- ) MACRO: napply ( n -- )
2 [a,b] 2 [a,b]
[ [ 1- ] [ ] bi '[ _ ntuck _ nslip ] ] [ [ 1- ] [ ] bi '[ _ ntuck _ nslip ] ]