{ $values { "n" "a starting index" } { "seq" sequence } { "quot" { $quotation "( elt -- ? )" } } { "i" "the index of the first match, or f" } { "elt" "the first matching element, or " { $link f } } }
{ $description "Applies the quotation to each element of the sequence in reverse order, until it outputs a true value or the start of the sequence is reached. If the quotation yields a true value for some sequence element, the word outputs the element index and the element itself. Otherwise, the word outputs an index of f and " { $link f } " as the element." } ;
-HELP: contains?
+HELP: any?
{ $values { "seq" sequence } { "quot" { $quotation "( elt -- ? )" } } { "?" "a boolean" } }
{ $description "Tests if the sequence contains an element satisfying the predicate, by applying the predicate to each element in turn until a true value is found. If the sequence is empty or if the end of the sequence is reached, outputs " { $link f } "." } ;
{ $values { "seq" sequence } { "n" "a non-negative integer" } { "elt" object } { "quot" { $quotation "( seq1 seq2 -- newseq )" } } { "newseq" "a new sequence" } }
{ $description "Outputs a new string sequence of " { $snippet "elt" } " repeated, that when appended to " { $snippet "seq" } ", yields a sequence of length " { $snippet "n" } ". If the length of " { $snippet "seq" } " is greater than " { $snippet "n" } ", this word outputs an empty sequence." } ;
-HELP: pad-left
+HELP: pad-head
{ $values { "seq" sequence } { "n" "a non-negative integer" } { "elt" object } { "padded" "a new sequence" } }
{ $description "Outputs a new sequence consisting of " { $snippet "seq" } " padded on the left with enough repetitions of " { $snippet "elt" } " to have the result be of length " { $snippet "n" } "." }
-{ $examples { $example "USING: io sequences ;" "{ \"ab\" \"quux\" } [ 5 CHAR: - pad-left print ] each" "---ab\n-quux" } } ;
+{ $examples { $example "USING: io sequences ;" "{ \"ab\" \"quux\" } [ 5 CHAR: - pad-head print ] each" "---ab\n-quux" } } ;
-HELP: pad-right
+HELP: pad-tail
{ $values { "seq" sequence } { "n" "a non-negative integer" } { "elt" object } { "padded" "a new sequence" } }
{ $description "Outputs a new sequence consisting of " { $snippet "seq" } " padded on the right with enough repetitions of " { $snippet "elt" } " to have the result be of length " { $snippet "n" } "." }
-{ $examples { $example "USING: io sequences ;" "{ \"ab\" \"quux\" } [ 5 CHAR: - pad-right print ] each" "ab---\nquux-" } } ;
+{ $examples { $example "USING: io sequences ;" "{ \"ab\" \"quux\" } [ 5 CHAR: - pad-tail print ] each" "ab---\nquux-" } } ;
HELP: sequence=
{ $values { "seq1" sequence } { "seq2" sequence } { "?" "a boolean" } }
}
{ $notes "Used to implement the " { $link filter } " word." } ;
-HELP: trim-left
+HELP: trim-head
{ $values
{ "seq" sequence } { "quot" quotation }
{ "newseq" sequence } }
{ $description "Removes elements starting from the left side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a new sequence." }
{ $example "" "USING: prettyprint math sequences ;"
- "{ 0 0 1 2 3 0 0 } [ zero? ] trim-left ."
+ "{ 0 0 1 2 3 0 0 } [ zero? ] trim-head ."
"{ 1 2 3 0 0 }"
} ;
-HELP: trim-left-slice
+HELP: trim-head-slice
{ $values
{ "seq" sequence } { "quot" quotation }
{ "slice" slice } }
{ $description "Removes elements starting from the left side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a slice" }
{ $example "" "USING: prettyprint math sequences ;"
- "{ 0 0 1 2 3 0 0 } [ zero? ] trim-left-slice ."
+ "{ 0 0 1 2 3 0 0 } [ zero? ] trim-head-slice ."
"T{ slice { from 2 } { to 7 } { seq { 0 0 1 2 3 0 0 } } }"
} ;
-HELP: trim-right
+HELP: trim-tail
{ $values
{ "seq" sequence } { "quot" quotation }
{ "newseq" sequence } }
{ $description "Removes elements starting from the right side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a new sequence." }
{ $example "" "USING: prettyprint math sequences ;"
- "{ 0 0 1 2 3 0 0 } [ zero? ] trim-right ."
+ "{ 0 0 1 2 3 0 0 } [ zero? ] trim-tail ."
"{ 0 0 1 2 3 }"
} ;
-HELP: trim-right-slice
+HELP: trim-tail-slice
{ $values
{ "seq" sequence } { "quot" quotation }
{ "slice" slice } }
{ $description "Removes elements starting from the right side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a slice." }
{ $example "" "USING: prettyprint math sequences ;"
- "{ 0 0 1 2 3 0 0 } [ zero? ] trim-right-slice ."
+ "{ 0 0 1 2 3 0 0 } [ zero? ] trim-tail-slice ."
"T{ slice { from 0 } { to 5 } { seq { 0 0 1 2 3 0 0 } } }"
} ;
"T{ slice { from 2 } { to 5 } { seq { 0 0 1 2 3 0 0 } } }"
} ;
-{ trim trim-slice trim-left trim-left-slice trim-right trim-right-slice } related-words
+{ trim trim-slice trim-head trim-head-slice trim-tail trim-tail-slice } related-words
HELP: sift
{ $values
{ $subsection concat }
{ $subsection join }
"A pair of words useful for aligning strings:"
-{ $subsection pad-left }
-{ $subsection pad-right } ;
+{ $subsection pad-head }
+{ $subsection pad-tail } ;
ARTICLE: "sequences-slices" "Subsequences and slices"
"Extracting a subsequence:"
{ $subsection push-if }
{ $subsection filter }
"Testing if a sequence contains elements satisfying a predicate:"
-{ $subsection contains? }
+{ $subsection any? }
{ $subsection all? }
{ $subsection "sequence-2combinators" }
{ $subsection "sequence-3combinators" } ;
ARTICLE: "sequences-trimming" "Trimming sequences"
"Trimming words:"
{ $subsection trim }
-{ $subsection trim-left }
-{ $subsection trim-right }
+{ $subsection trim-head }
+{ $subsection trim-tail }
"Potentially more efficient trim:"
{ $subsection trim-slice }
-{ $subsection trim-left-slice }
-{ $subsection trim-right-slice } ;
+{ $subsection trim-head-slice }
+{ $subsection trim-tail-slice } ;
ARTICLE: "sequences-destructive-discussion" "When to use destructive operations"
"Constructive (non-destructive) operations should be preferred where possible because code without side-effects is usually more re-usable and easier to reason about. There are two main reasons to use destructive operations:"
projects / factor.git / blobdiff