Commit 335cb1ee authored by Michael Heerdegen's avatar Michael Heerdegen
Browse files

* lisp/emacs-lisp/pcase.el (pcase): Tweak docstring.

parent 5d1e2fec
......@@ -107,7 +107,7 @@
;;;###autoload
(defmacro pcase (exp &rest cases)
"Perform ML-style pattern matching on EXP.
"Eval EXP and perform ML-style pattern matching on that value.
CASES is a list of elements of the form (PATTERN CODE...).
Patterns can take the following forms:
......@@ -115,7 +115,7 @@ Patterns can take the following forms:
SYMBOL matches anything and binds it to SYMBOL.
(or PAT...) matches if any of the patterns matches.
(and PAT...) matches if all the patterns match.
\\='VAL matches if the object is `equal' to VAL
\\='VAL matches if the object is `equal' to VAL.
ATOM is a shorthand for \\='ATOM.
ATOM can be a keyword, an integer, or a string.
(pred FUN) matches if FUN applied to the object returns non-nil.
......@@ -131,11 +131,11 @@ FUN can take the form
which is the value being matched.
So a FUN of the form SYMBOL is equivalent to one of the form (FUN).
FUN can refer to variables bound earlier in the pattern.
FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
and two identical calls can be merged into one.
E.g. you can match pairs where the cdr is larger than the car with a pattern
like \\=`(,a . ,(pred (< a))) or, with more checks:
\\=`(,(and a (pred numberp)) . ,(and (pred numberp) (pred (< a))))
FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
and two identical calls can be merged into one.
Additional patterns can be defined via `pcase-defmacro'.
Currently, the following patterns are provided this way:"
......
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