diff options
Diffstat (limited to 'lisp/emacs-lisp/generator.el')
| -rw-r--r-- | lisp/emacs-lisp/generator.el | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/lisp/emacs-lisp/generator.el b/lisp/emacs-lisp/generator.el index 4ae20ba4205..ac1412704b0 100644 --- a/lisp/emacs-lisp/generator.el +++ b/lisp/emacs-lisp/generator.el @@ -143,8 +143,7 @@ the CPS state machinery." (setf ,static-var ,dynamic-var))))) (defmacro cps--with-dynamic-binding (dynamic-var static-var &rest body) - "Evaluate BODY such that generated atomic evaluations run with -DYNAMIC-VAR bound to STATIC-VAR." + "Run BODY's atomic evaluations run with DYNAMIC-VAR bound to STATIC-VAR." (declare (indent 2)) `(cps--with-value-wrapper (cps--make-dynamic-binding-wrapper ,dynamic-var ,static-var) @@ -291,22 +290,28 @@ DYNAMIC-VAR bound to STATIC-VAR." (cps--transform-1 `(progn ,@rest) next-state))) - ;; Process `let' in a helper function that transforms it into a - ;; let* with temporaries. + (`(,(or 'let 'let*) () . ,body) + (cps--transform-1 `(progn ,@body) next-state)) + + ;; Transform multi-variable `let' into `let*': + ;; (let ((v1 e1) ... (vN eN)) BODY) + ;; -> (let* ((t1 e1) ... (tN-1 eN-1) (vN eN) (v1 t1) (vN-1 tN-1)) BODY) (`(let ,bindings . ,body) (let* ((bindings (cl-loop for binding in bindings collect (if (symbolp binding) (list binding nil) binding))) - (temps (cl-loop for (var _value-form) in bindings + (butlast-bindings (butlast bindings)) + (temps (cl-loop for (var _value-form) in butlast-bindings collect (cps--add-binding var)))) (cps--transform-1 `(let* ,(append - (cl-loop for (_var value-form) in bindings + (cl-loop for (_var value-form) in butlast-bindings for temp in temps collect (list temp value-form)) - (cl-loop for (var _binding) in bindings + (last bindings) + (cl-loop for (var _binding) in butlast-bindings for temp in temps collect (list var temp))) ,@body) @@ -315,9 +320,6 @@ DYNAMIC-VAR bound to STATIC-VAR." ;; Process `let*' binding: process one binding at a time. Flatten ;; lexical bindings. - (`(let* () . ,body) - (cps--transform-1 `(progn ,@body) next-state)) - (`(let* (,binding . ,more-bindings) . ,body) (let* ((var (if (symbolp binding) binding (car binding))) (value-form (car (cdr-safe binding))) @@ -467,7 +469,7 @@ DYNAMIC-VAR bound to STATIC-VAR." (guard (cps--special-form-p name)) (guard (not (memq name cps-standard-special-forms)))) name ; Shut up byte compiler - (error "special form %S incorrect or not supported" form)) + (error "Special form %S incorrect or not supported" form)) ;; Process regular function applications with nontrivial ;; parameters, converting them to applications of trivial @@ -633,7 +635,7 @@ modified copy." ;; If we're exiting non-locally (error, quit, ;; etc.) close the iterator. ,(cps--make-close-iterator-form terminal-state))))) - (t (error "unknown iterator operation %S" op)))))) + (t (error "Unknown iterator operation %S" op)))))) ,(when finalizer-symbol '(funcall iterator :stash-finalizer @@ -642,12 +644,11 @@ modified copy." (iter-close iterator))))) iterator)))) -(defun iter-yield (value) +(defun iter-yield (_value) "When used inside a generator, yield control to caller. The caller of `iter-next' receives VALUE, and the next call to `iter-next' resumes execution with the form immediately following this `iter-yield' call." - (identity value) (error "`iter-yield' used outside a generator")) (defmacro iter-yield-from (value) @@ -668,7 +669,7 @@ sub-iterator function returns via `iter-end-of-sequence'." (iter-close ,valsym))))) (defmacro iter-defun (name arglist &rest body) - "Creates a generator NAME. + "Create a generator NAME that accepts ARGLIST as its arguments. When called as a function, NAME returns an iterator value that encapsulates the state of a computation that produces a sequence of values. Callers can retrieve each value using `iter-next'." @@ -711,7 +712,7 @@ iterator cannot supply more values." (defun iter-close (iterator) "Terminate an iterator early. -Run any unwind-protect handlers in scope at the point ITERATOR +Run any `unwind-protect' handlers in scope at the point ITERATOR is blocked." (funcall iterator :close nil)) |