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Move the when-let family of macros to subr.el
* lisp/subr.el (internal--build-binding) (internal--build-bindings): Moved from subr-x.el and rewritten to not use the threading macro. (if-let*, when-let*, and-let*, if-let, when-let): Moved from subr-x.el. This avoids breaking the build every time somebody uses these macros in functions that end up being called during bootstrap.
This commit is contained in:
Lars Ingebrigtsen
parent
93549c2b28
commit
b05a103ea7
2 changed files with 96 additions and 110 deletions
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@ -81,116 +81,6 @@ Note how the single `-' got converted into a list before
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threading."
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threading."
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(declare (indent 0) (debug thread-first))
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(declare (indent 0) (debug thread-first))
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`(internal--thread-argument nil ,@forms))
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`(internal--thread-argument nil ,@forms))
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(defsubst internal--listify (elt)
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"Wrap ELT in a list if it is not one.
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If ELT is of the form ((EXPR)), listify (EXPR) with a dummy symbol."
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(cond
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((symbolp elt) (list elt elt))
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((null (cdr elt))
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(list (make-symbol "s") (car elt)))
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(t elt)))
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(defsubst internal--check-binding (binding)
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"Check BINDING is properly formed."
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(when (> (length binding) 2)
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(signal
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'error
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(cons "`let' bindings can have only one value-form" binding)))
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binding)
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(defsubst internal--build-binding-value-form (binding prev-var)
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"Build the conditional value form for BINDING using PREV-VAR."
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(let ((var (car binding)))
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`(,var (and ,prev-var ,(cadr binding)))))
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(defun internal--build-binding (binding prev-var)
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"Check and build a single BINDING with PREV-VAR."
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(thread-first
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binding
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internal--listify
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internal--check-binding
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(internal--build-binding-value-form prev-var)))
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(defun internal--build-bindings (bindings)
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"Check and build conditional value forms for BINDINGS."
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(let ((prev-var t))
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(mapcar (lambda (binding)
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(let ((binding (internal--build-binding binding prev-var)))
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(setq prev-var (car binding))
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binding))
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bindings)))
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(defmacro if-let* (varlist then &rest else)
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"Bind variables according to VARLIST and evaluate THEN or ELSE.
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This is like `if-let' but doesn't handle a VARLIST of the form
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\(SYMBOL SOMETHING) specially."
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(declare (indent 2)
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(debug ((&rest [&or symbolp (symbolp form) (form)])
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body)))
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(if varlist
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`(let* ,(setq varlist (internal--build-bindings varlist))
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(if ,(caar (last varlist))
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,then
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,@else))
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`(let* () ,then)))
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(defmacro when-let* (varlist &rest body)
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"Bind variables according to VARLIST and conditionally evaluate BODY.
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This is like `when-let' but doesn't handle a VARLIST of the form
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\(SYMBOL SOMETHING) specially."
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(declare (indent 1) (debug if-let*))
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(list 'if-let* varlist (macroexp-progn body)))
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(defmacro and-let* (varlist &rest body)
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"Bind variables according to VARLIST and conditionally evaluate BODY.
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Like `when-let*', except if BODY is empty and all the bindings
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are non-nil, then the result is non-nil."
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(declare (indent 1) (debug if-let*))
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(let (res)
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(if varlist
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`(let* ,(setq varlist (internal--build-bindings varlist))
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(when ,(setq res (caar (last varlist)))
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,@(or body `(,res))))
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`(let* () ,@(or body '(t))))))
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;;;###autoload
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(defmacro if-let (spec then &rest else)
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"Bind variables according to SPEC and evaluate THEN or ELSE.
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Evaluate each binding in turn, as in `let*', stopping if a
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binding value is nil. If all are non-nil return the value of
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THEN, otherwise the last form in ELSE.
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Each element of SPEC is a list (SYMBOL VALUEFORM) that binds
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SYMBOL to the value of VALUEFORM. An element can additionally be
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of the form (VALUEFORM), which is evaluated and checked for nil;
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i.e. SYMBOL can be omitted if only the test result is of
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interest. It can also be of the form SYMBOL, then the binding of
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SYMBOL is checked for nil.
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As a special case, interprets a SPEC of the form \(SYMBOL SOMETHING)
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like \((SYMBOL SOMETHING)). This exists for backward compatibility
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with an old syntax that accepted only one binding."
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(declare (indent 2)
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(debug ([&or (symbolp form) ; must be first, Bug#48489
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(&rest [&or symbolp (symbolp form) (form)])]
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body)))
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(when (and (<= (length spec) 2)
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(not (listp (car spec))))
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;; Adjust the single binding case
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(setq spec (list spec)))
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(list 'if-let* spec then (macroexp-progn else)))
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;;;###autoload
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(defmacro when-let (spec &rest body)
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"Bind variables according to SPEC and conditionally evaluate BODY.
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Evaluate each binding in turn, stopping if a binding value is nil.
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If all are non-nil, return the value of the last form in BODY.
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The variable list SPEC is the same as in `if-let'."
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(declare (indent 1) (debug if-let))
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(list 'if-let spec (macroexp-progn body)))
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(defsubst hash-table-empty-p (hash-table)
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(defsubst hash-table-empty-p (hash-table)
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"Check whether HASH-TABLE is empty (has 0 elements)."
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"Check whether HASH-TABLE is empty (has 0 elements)."
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(zerop (hash-table-count hash-table)))
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(zerop (hash-table-count hash-table)))
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96
lisp/subr.el
96
lisp/subr.el
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@ -2371,6 +2371,102 @@ Affects only hooks run in the current buffer."
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(let ((delay-mode-hooks t))
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(let ((delay-mode-hooks t))
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,@body)))
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,@body)))
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;;; `when-let' and friends.
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(defun internal--build-binding (binding prev-var)
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"Check and build a single BINDING with PREV-VAR."
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(setq binding
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(cond
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((symbolp binding)
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(list binding binding))
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((null (cdr binding))
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(list (make-symbol "s") (car binding)))
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(t binding)))
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(when (> (length binding) 2)
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(signal 'error
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(cons "`let' bindings can have only one value-form" binding)))
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(let ((var (car binding)))
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`(,var (and ,prev-var ,(cadr binding)))))
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(defun internal--build-bindings (bindings)
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"Check and build conditional value forms for BINDINGS."
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(let ((prev-var t))
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(mapcar (lambda (binding)
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(let ((binding (internal--build-binding binding prev-var)))
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(setq prev-var (car binding))
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binding))
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bindings)))
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(defmacro if-let* (varlist then &rest else)
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"Bind variables according to VARLIST and evaluate THEN or ELSE.
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This is like `if-let' but doesn't handle a VARLIST of the form
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\(SYMBOL SOMETHING) specially."
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(declare (indent 2)
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(debug ((&rest [&or symbolp (symbolp form) (form)])
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body)))
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(if varlist
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`(let* ,(setq varlist (internal--build-bindings varlist))
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(if ,(caar (last varlist))
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,then
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,@else))
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`(let* () ,then)))
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(defmacro when-let* (varlist &rest body)
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"Bind variables according to VARLIST and conditionally evaluate BODY.
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This is like `when-let' but doesn't handle a VARLIST of the form
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\(SYMBOL SOMETHING) specially."
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(declare (indent 1) (debug if-let*))
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(list 'if-let* varlist (macroexp-progn body)))
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(defmacro and-let* (varlist &rest body)
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"Bind variables according to VARLIST and conditionally evaluate BODY.
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Like `when-let*', except if BODY is empty and all the bindings
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are non-nil, then the result is non-nil."
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(declare (indent 1) (debug if-let*))
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(let (res)
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(if varlist
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`(let* ,(setq varlist (internal--build-bindings varlist))
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(when ,(setq res (caar (last varlist)))
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,@(or body `(,res))))
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`(let* () ,@(or body '(t))))))
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(defmacro if-let (spec then &rest else)
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"Bind variables according to SPEC and evaluate THEN or ELSE.
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Evaluate each binding in turn, as in `let*', stopping if a
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binding value is nil. If all are non-nil return the value of
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THEN, otherwise the last form in ELSE.
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Each element of SPEC is a list (SYMBOL VALUEFORM) that binds
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SYMBOL to the value of VALUEFORM. An element can additionally be
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of the form (VALUEFORM), which is evaluated and checked for nil;
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i.e. SYMBOL can be omitted if only the test result is of
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interest. It can also be of the form SYMBOL, then the binding of
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SYMBOL is checked for nil.
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As a special case, interprets a SPEC of the form \(SYMBOL SOMETHING)
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like \((SYMBOL SOMETHING)). This exists for backward compatibility
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with an old syntax that accepted only one binding."
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(declare (indent 2)
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(debug ([&or (symbolp form) ; must be first, Bug#48489
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(&rest [&or symbolp (symbolp form) (form)])]
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body)))
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(when (and (<= (length spec) 2)
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(not (listp (car spec))))
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;; Adjust the single binding case
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(setq spec (list spec)))
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(list 'if-let* spec then (macroexp-progn else)))
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(defmacro when-let (spec &rest body)
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"Bind variables according to SPEC and conditionally evaluate BODY.
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Evaluate each binding in turn, stopping if a binding value is nil.
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If all are non-nil, return the value of the last form in BODY.
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The variable list SPEC is the same as in `if-let'."
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(declare (indent 1) (debug if-let))
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(list 'if-let spec (macroexp-progn body)))
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;; PUBLIC: find if the current mode derives from another.
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;; PUBLIC: find if the current mode derives from another.
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(defun provided-mode-derived-p (mode &rest modes)
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(defun provided-mode-derived-p (mode &rest modes)
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