masscollaborationlabs/emacs
2
0
Fork 0
mirror of https://github.com/masscollaborationlabs/emacs.git synced 2025-07-16 17:00:06 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Clarify lexical binding with symbol args behavior

Browse source 
* doc/lispref/variables.texi (Lexical Binding): Clarify that symbol
arguments always refer to dynamic values (Bug #23781).  Remove mention
of obsolete restriction regarding lexical binding for defun and
defmacro, this no longer applies since 61b108cc 2012-05-29 "*
lisp/emacs-lisp/byte-run.el (defmacro, defun): Move from C...".
This commit is contained in:
Noam Postavsky 2016-06-24 20:39:24 -04:00
parent f981b31367
commit 850ba444a7
1 changed files with 8 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

14
doc/lispref/variables.texi
View file

@ -974,7 +974,7 @@ itself.
@cindex lexical environment @cindex lexical environment
Here is how lexical binding works. Each binding construct defines a Here is how lexical binding works. Each binding construct defines a
@dfn{lexical environment}, specifying the symbols that are bound @dfn{lexical environment}, specifying the variables that are bound
within the construct and their local values. When the Lisp evaluator within the construct and their local values. When the Lisp evaluator
wants the current value of a variable, it looks first in the lexical wants the current value of a variable, it looks first in the lexical
environment; if the variable is not specified in there, it looks in environment; if the variable is not specified in there, it looks in
@ -1032,11 +1032,13 @@ lives on even after the @code{let} binding construct has exited. Each
time we evaluate the closure, it increments @code{x}, using the time we evaluate the closure, it increments @code{x}, using the
binding of @code{x} in that lexical environment. binding of @code{x} in that lexical environment.
Note that functions like @code{symbol-value}, @code{boundp}, and Note that unlike dynamic variables which are tied to the symbol
@code{set} only retrieve or modify a variable's dynamic binding object itself, the relationship between lexical variables and symbols
(i.e., the contents of its symbol's value cell). Also, the code in is only present in the interpreter (or compiler). Therefore,
the body of a @code{defun} or @code{defmacro} cannot refer to functions which take a symbol argument (like @code{symbol-value},
surrounding lexical variables. @code{boundp}, and @code{set}) can only retrieve or modify a
variable's dynamic binding (i.e., the contents of its symbol's value
cell).
@node Using Lexical Binding @node Using Lexical Binding
@subsection Using Lexical Binding @subsection Using Lexical Binding