Macro MATCH
Package:
COMMON-LISP.EXTENSIONS.DATA-AND-CONTROL-FLOW.UNIFICATION
Syntax:
match (template object &key substitution errorp error-value) &body forms => results*
Arguments and Values:
template---a unification template
object---an object
substitution---a substitution
errorp---a generalized boolean
error-value---an object
forms---an implicit progn
results---the values returned by forms
Description:
MATCH sets up a lexical environment to evaluate forms after a unification operation. MATCH unifies a template and an object and then sets up a lexical environment where the variables present in the template are bound lexically. Note that both variable names '?FOO' and 'FOO' are bound for convenience.
The MATCH form returns the values returned by the evaluation of the last of the forms.
If errorp is non-NIL (the default) then the form raises a UNIFICATION-FAILURE, otherwise the result of evaluating error-value, whose default is NIL is returned.
Affected By:
None.
Exceptional Situations:
See above.
See Also:
UNIFY, UNIFICATION-FAILURE
Notes:
Note that UNIFICATION-FAILUREs raising from the evaluation of forms will also be caught and handled by the enclosing MATCH according to errorp settings.