API for fcase
This file defines a generic "case" macro called "fcase" which takes
the equality-testing function as an argument. It also defines a
traditional "case" macro that tests using "=" and variants that
test for regular expressions and class membership.
Note (December 23, 2008): This library has been supplanted by the
inclusion of "condp" in clojure.core as of Clojure SVN rev. 1180.
Public Variables and Functions
Usage: (case test-value & clauses)
Like cond, but test-value is compared against the value of each
test expression with =. If they are equal, executes the "body"
expression. Optional last expression is executed if none of the
test expressions match.
Usage: (fcase compare-fn case-value & test-expr-clauses)
Generic switch/case macro. 'fcase' is short for 'function case'.
The 'compare-fn' is a fn of two arguments.
The 'test-expr-clauses' are value-expression pairs without
surrounding parentheses, like in Clojure's 'cond'.
The 'case-value' is evaluated once and cached. Then, 'compare-fn'
is called once for each clause, with the clause's test value as its
first argument and 'case-value' as its second argument. If
'compare-fn' returns logical true, the clause's expression is
evaluated and returned. If 'compare-fn' returns false/nil, we go to
the next test value.
If 'test-expr-clauses' contains an odd number of items, the last
item is the default expression evaluated if no case-value matches.
If there is no default expression and no case-value matches, fcase
See specific forms of this macro in 'case' and 're-case'.
The test expressions in 'fcase' are always evaluated linearly, in
order. For a large number of case expressions it may be more
efficient to use a hash lookup.
Usage: (in-case test-value & clauses)
Like case, but test expressions are sequences. The test expression
is true if any item in the sequence is equal (tested with '=') to
the test value.
Usage: (instance-case test-value & clauses)
Like case, but the test expressions are Java class names, tested with
Usage: (re-case test-value & clauses)
Like case, but the test expressions are regular expressions, tested