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* lisp/emacs-lisp/pcase.el: Improve docstrings.

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This commit is contained in:
Stefan Monnier 2018-10-30 14:24:31 -04:00
parent 86abbb3cb8
commit eb903d8f20
1 changed files with 12 additions and 6 deletions
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18
lisp/emacs-lisp/pcase.el
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@ -266,7 +266,8 @@ variable name being but a special case of it)."
(defmacro pcase-let* (bindings &rest body) (defmacro pcase-let* (bindings &rest body)
"Like `let*' but where you can use `pcase' patterns for bindings. "Like `let*' but where you can use `pcase' patterns for bindings.
BODY should be an expression, and BINDINGS should be a list of bindings BODY should be an expression, and BINDINGS should be a list of bindings
of the form (PAT EXP)." of the form (PATTERN EXP).
See `pcase-let' for discussion of how PATTERN is matched."
(declare (indent 1) (declare (indent 1)
(debug ((&rest (pcase-PAT &optional form)) body))) (debug ((&rest (pcase-PAT &optional form)) body)))
(let ((cached (gethash bindings pcase--memoize))) (let ((cached (gethash bindings pcase--memoize)))
@ -281,10 +282,11 @@ of the form (PAT EXP)."
(defmacro pcase-let (bindings &rest body) (defmacro pcase-let (bindings &rest body)
"Like `let' but where you can use `pcase' patterns for bindings. "Like `let' but where you can use `pcase' patterns for bindings.
BODY should be a list of expressions, and BINDINGS should be a list of bindings BODY should be a list of expressions, and BINDINGS should be a list of bindings
of the form (PAT EXP). of the form (PATTERN EXP).
The macro is expanded and optimized under the assumption that those The PATTERNs are only used to extract data, so the code does not test
patterns *will* match, so a mismatch may go undetected or may cause whether the data does match the corresponding patterns: a mismatch
any kind of error." may signal an error or may go undetected, binding variables to arbitrary
values, such as nil."
(declare (indent 1) (debug pcase-let*)) (declare (indent 1) (debug pcase-let*))
(if (null (cdr bindings)) (if (null (cdr bindings))
`(pcase-let* ,bindings ,@body) `(pcase-let* ,bindings ,@body)
@ -302,7 +304,11 @@ any kind of error."
;;;###autoload ;;;###autoload
(defmacro pcase-dolist (spec &rest body) (defmacro pcase-dolist (spec &rest body)
"Like `dolist' but where the binding can be a `pcase' pattern. "Superset of `dolist' where the VAR binding can be a `pcase' PATTERN.
More specifically, this is just a shorthand for the following combination
of `dolist' and `pcase-let':
(dolist (x LIST) (pcase-let ((PATTERN x)) BODY...))
\n(fn (PATTERN LIST) BODY...)" \n(fn (PATTERN LIST) BODY...)"
(declare (indent 1) (debug ((pcase-PAT form) body))) (declare (indent 1) (debug ((pcase-PAT form) body)))
(if (pcase--trivial-upat-p (car spec)) (if (pcase--trivial-upat-p (car spec))