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Backport some docstring updates, warn about upcoming obsolescence

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Try to save people some time if they're developing on Emacs 30.x.

Do not merge to master.

* lisp/subr.el (if-let*, when-let*, if-let, when-let): Move
docstring text around so that if-let* and when-let* descriptions
no longer refer to if-let and when-let.  Note that if-let and
when-let will be marked obsolete, and recommend if-let*,
when-let* and and-let* for new code.
This commit is contained in:
Sean Whitton 2024-10-27 11:37:42 +08:00
parent 3f94b979d8
commit bd2b064438
1 changed files with 25 additions and 19 deletions
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@ -2625,8 +2625,17 @@ Affects only hooks run in the current buffer."
(defmacro if-let* (varlist then &rest else)
"Bind variables according to VARLIST and evaluate THEN or ELSE.
This is like `if-let' but doesn't handle a VARLIST of the form
\(SYMBOL SOMETHING) specially."
Evaluate each binding in turn, as in `let*', stopping if a
binding value is nil. If all are non-nil return the value of
THEN, otherwise the value of the last form in ELSE, or nil if
there are none.
Each element of VARLIST is a list (SYMBOL VALUEFORM) that binds
SYMBOL to the value of VALUEFORM. An element can additionally be
of the form (VALUEFORM), which is evaluated and checked for nil;
i.e. SYMBOL can be omitted if only the test result is of
interest. It can also be of the form SYMBOL, then the binding of
SYMBOL is checked for nil."
(declare (indent 2)
(debug ((&rest [&or symbolp (symbolp form) (form)])
body)))
@ -2639,8 +2648,10 @@ This is like `if-let' but doesn't handle a VARLIST of the form
(defmacro when-let* (varlist &rest body)
"Bind variables according to VARLIST and conditionally evaluate BODY.
This is like `when-let' but doesn't handle a VARLIST of the form
\(SYMBOL SOMETHING) specially.
Evaluate each binding in turn, stopping if a binding value is nil.
If all are non-nil, return the value of the last form in BODY.
The variable list VARLIST is the same as in `if-let*'.
See also `and-let*'."
(declare (indent 1) (debug if-let*))
@ -2667,21 +2678,13 @@ for forms evaluated for side-effect with returned values ignored."
(defmacro if-let (spec then &rest else)
"Bind variables according to SPEC and evaluate THEN or ELSE.
Evaluate each binding in turn, as in `let*', stopping if a
binding value is nil. If all are non-nil return the value of
THEN, otherwise the value of the last form in ELSE, or nil if
there are none.
This is like `if-let*' except, as a special case, interpret a SPEC of
the form \(SYMBOL SOMETHING) like \((SYMBOL SOMETHING)). This exists
for backward compatibility with an old syntax that accepted only one
binding.
Each element of SPEC is a list (SYMBOL VALUEFORM) that binds
SYMBOL to the value of VALUEFORM. An element can additionally be
of the form (VALUEFORM), which is evaluated and checked for nil;
i.e. SYMBOL can be omitted if only the test result is of
interest. It can also be of the form SYMBOL, then the binding of
SYMBOL is checked for nil.
As a special case, interprets a SPEC of the form \(SYMBOL SOMETHING)
like \((SYMBOL SOMETHING)). This exists for backward compatibility
with an old syntax that accepted only one binding."
This macro will be marked obsolete in Emacs 31.1; prefer `if-let*' in
new code."
(declare (indent 2)
(debug ([&or (symbolp form) ; must be first, Bug#48489
(&rest [&or symbolp (symbolp form) (form)])]
@ -2697,7 +2700,10 @@ with an old syntax that accepted only one binding."
Evaluate each binding in turn, stopping if a binding value is nil.
If all are non-nil, return the value of the last form in BODY.
The variable list SPEC is the same as in `if-let'."
The variable list SPEC is the same as in `if-let'.
This macro will be marked obsolete in Emacs 31.1; prefer `when-let*' and
`and-let*' in new code."
(declare (indent 1) (debug if-let))
(list 'if-let spec (macroexp-progn body)))