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add filter-as to sequences

db4
Joe Groff 2009-10-22 17:28:01 -05:00
parent 1a7b4d7c63
commit e31ed3eda4
2 changed files with 13 additions and 2 deletions
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5
core/sequences/sequences-docs.factor
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@ -426,6 +426,10 @@ HELP: filter
{ $values { "seq" sequence } { "quot" { $quotation "( elt -- ? )" } } { "subseq" "a new sequence" } } { $values { "seq" sequence } { "quot" { $quotation "( elt -- ? )" } } { "subseq" "a new sequence" } }
{ $description "Applies the quotation to each element in turn, and outputs a new sequence containing the elements of the original sequence for which the quotation output a true value." } ; { $description "Applies the quotation to each element in turn, and outputs a new sequence containing the elements of the original sequence for which the quotation output a true value." } ;
HELP: filter-as
{ $values { "seq" sequence } { "quot" { $quotation "( elt -- ? )" } } { "exemplar" sequence } { "subseq" "a new sequence" } }
{ $description "Applies the quotation to each element in turn, and outputs a new sequence of the same type as " { $snippet "exemplar" } " containing the elements of the original sequence for which the quotation output a true value." } ;
HELP: filter-here HELP: filter-here
{ $values { "seq" "a resizable mutable sequence" } { "quot" { $quotation "( elt -- ? )" } } } { $values { "seq" "a resizable mutable sequence" } { "quot" { $quotation "( elt -- ? )" } } }
{ $description "Applies the quotation to each element in turn, and removes elements for which the quotation outputs a false value." } { $description "Applies the quotation to each element in turn, and removes elements for which the quotation outputs a false value." }
@ -1512,6 +1516,7 @@ ARTICLE: "sequences-combinators" "Sequence combinators"
"Filtering:" "Filtering:"
{ $subsections { $subsections
filter filter
filter-as
partition partition
} }
"Testing if a sequence contains elements satisfying a predicate:" "Testing if a sequence contains elements satisfying a predicate:"

10
core/sequences/sequences.factor
View File

@ -483,11 +483,17 @@ PRIVATE>
: push-if ( elt quot accum -- ) : push-if ( elt quot accum -- )
[ keep ] dip rot [ push ] [ 2drop ] if ; inline [ keep ] dip rot [ push ] [ 2drop ] if ; inline
: pusher-for ( quot exemplar -- quot accum )
[ length ] keep new-resizable [ [ push-if ] 2curry ] keep ; inline
: pusher ( quot -- quot accum ) : pusher ( quot -- quot accum )
V{ } clone [ [ push-if ] 2curry ] keep ; inline V{ } pusher-for ; inline
: filter-as ( seq quot exemplar -- subseq )
dup [ pusher-for [ each ] dip ] curry dip like ; inline
: filter ( seq quot -- subseq ) : filter ( seq quot -- subseq )
over [ pusher [ each ] dip ] dip like ; inline over filter-as ; inline
: push-either ( elt quot accum1 accum2 -- ) : push-either ( elt quot accum1 accum2 -- )
[ keep swap ] 2dip ? push ; inline [ keep swap ] 2dip ? push ; inline