From 80ba4c170756049a101b4e6692882ac30ba5e1a5 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Wed, 25 May 2022 17:53:39 -0400 Subject: eval.c: New functions `defvar-1` and `defconst-1` (bug#55156) The bytecode interpreter can't directly call special forms, so the byte-compiler usually converts special forms into some sequence of byte codes (basically, providing a duplicate definition of the special form). There are still two exceptions to this: `defconst` and `defvar`, where the compiler instead generates a convoluted chunk of code like: (funcall '(lambda (x) (defvar x )) ) where the quote makes sure we keep the function non-compiled, so as to end up running the special form at run time. Get rid of this workaround by introducing `defvar-1` and `defconst-1` which provide a *functional* interface to the functionality of the corresponding special form. * src/eval.c (defvar, Fdefvar_1, Fdefconst_1): New functions, extracted from `Fdefvar` and `Fdefconst`. (Fdefvar, Fdefconst): Use them. (syms_of_eval): `defsubr` the new functions. * lisp/emacs-lisp/bytecomp.el (byte-compile-tmp-var): Delete const. (byte-compile-defvar): Simplify using the new functions. * doc/lispref/variables.texi (Defining Variables): Adjust the doc of `defvar` to reflect the actual semantics implemented. --- doc/lispref/variables.texi | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'doc/lispref/variables.texi') diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi index f0e3f337a69..c29547d00db 100644 --- a/doc/lispref/variables.texi +++ b/doc/lispref/variables.texi @@ -527,10 +527,11 @@ If @var{symbol} has a buffer-local binding in the current buffer, rather than the buffer-local binding. It sets the default value if the default value is void. @xref{Buffer-Local Variables}. -If @var{symbol} is already lexically bound (e.g., if the @code{defvar} -form occurs in a @code{let} form with lexical binding enabled), then -@code{defvar} sets the dynamic value. The lexical binding remains in -effect until its binding construct exits. @xref{Variable Scoping}. +If @var{symbol} is already let bound (e.g., if the @code{defvar} +form occurs in a @code{let} form), then @code{defvar} sets the toplevel +default value, like @code{set-default-toplevel-value}. +The let binding remains in effect until its binding construct exits. +@xref{Variable Scoping}. @cindex @code{eval-defun}, and @code{defvar} forms @cindex @code{eval-last-sexp}, and @code{defvar} forms -- cgit v1.2.3