Keywords are symbolic constants which evaluate to themselves. A keyword is a symbol whose first (or last) character is a colon (":").
keyword obj | STKLOS Procedure |
Returns #t if obj is a keyword, otherwise returns #f .
(keyword? 'foo) => #f (keyword? ':foo) => #t (keyword? 'foo:) => #t (keyword? :foo) => #t (keyword? foo:) => #t |
make-keyword s | STKLOS Procedure |
Builds a keyword from the given s . The parameter s must be a symbol
or a string.
(make-keyword "test") => :test (make-keyword 'test) => :test (make-keyword ":hello") => ::hello |
keyword->string key | STKLOS Procedure |
Returns the name of key as a string. The result does not contain a colon.
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key-get list key | STKLOS Procedure |
key-get list key default | STKLOS Procedure |
List must be a list of keywords and their respective values.
key-get scans the list and returns the value
associated with the given key . If key does
not appear in an odd position in list , the specified
default is returned, or an error is raised if no default was
specified.
(key-get '(:one 1 :two 2) :one) => 1 (key-get '(:one 1 :two 2) :four #f) => #f (key-get '(:one 1 :two 2) :four) => error |
key-set! list key value | STKLOS Procedure |
List must be a list of keywords and their respective values.
key-set! sets the value associated to key in the keyword list.
If the key is already present in list , the keyword list is
physically changed.
(let ((l '(:one 1 :two 2))) (set! l (key-set! l :three 3)) (cons (key-get l :one) (key-get l :three)) => (1 . 3) |
key-delete! list key | STKLOS Procedure |
List must be a list of keywords and their respective values.
key-delete remove the key and its associated value of the keyword
list. The key can be absent of the list.
(key-delete '(:one 1 :two 2) :one) => (:one 1) (key-delete '(:one 1 :two 2) :three) => (:one 1 :two 2) |