23 lines
945 B
Factor
23 lines
945 B
Factor
|
USING: combinators help.markup help.syntax ;
|
||
|
|
|
||
|
|
IN: combinators.extras
|
||
|
|
|
||
|
|
HELP: cond-case
|
||
|
|
{ $values { "assoc" "a sequence of quotation pairs and an optional quotation" } }
|
||
|
|
{ $description
|
||
|
"Similar to " { $link case } ", this evaluates an " { $snippet "obj" } " according to the first quotation in each pair. If any quotation returns true, calls the second quotation without " { $snippet "obj" } " on the stack."
|
||
|
|
$nl
|
||
|
|
"If there is no quotation that returns true, the default case is taken. If the last element of " { $snippet "assoc" } " is a quotation, the quotation is called with " { $snippet "obj" } " on the stack. Otherwise, a " { $link no-cond } " error is raised."
|
||
|
|
}
|
||
|
|
{ $examples
|
||
|
|
{ $example
|
||
|
|
"USING: combinators.extras io kernel math ;"
|
||
|
|
"0 {"
|
||
|
|
" { [ 0 > ] [ \"positive\" ] }"
|
||
|
|
" { [ 0 < ] [ \"negative\" ] }"
|
||
|
|
" [ drop \"zero\" ]"
|
||
|
|
"} cond-case print"
|
||
|
|
"zero"
|
||
|
|
}
|
||
|
|
} ;
|