Commit 606cdb89 authored by Juanma Barranquero's avatar Juanma Barranquero
Browse files

(user_variable_p_eh): New function.

(Fuser_variable_p): Use it.  Clarify docstring.
Return t for aliases of user options, nil for alias loops.
parent 27484eb0
......@@ -889,12 +889,24 @@ usage: (defconst SYMBOL INITVALUE [DOCSTRING]) */)
return sym;
}
/* Error handler used in Fuser_variable_p. */
static Lisp_Object
user_variable_p_eh (ignore)
Lisp_Object ignore;
{
return Qnil;
}
DEFUN ("user-variable-p", Fuser_variable_p, Suser_variable_p, 1, 1, 0,
doc: /* Returns t if VARIABLE is intended to be set and modified by users.
doc: /* Return t if VARIABLE is intended to be set and modified by users.
\(The alternative is a variable used internally in a Lisp program.)
Determined by whether the first character of the documentation
for the variable is `*' or if the variable is customizable (has a non-nil
value of `standard-value' or of `custom-autoload' on its property list). */)
A variable is a user variable if
\(1) the first character of its documentation is `*', or
\(2) it is customizable (its property list contains a non-nil value
of `standard-value' or `custom-autoload'), or
\(3) it is an alias for another user variable.
Return nil if VARIABLE is an alias and there is a loop in the
chain of symbols. */)
(variable)
Lisp_Object variable;
{
......@@ -903,23 +915,37 @@ value of `standard-value' or of `custom-autoload' on its property list). */)
if (!SYMBOLP (variable))
return Qnil;
documentation = Fget (variable, Qvariable_documentation);
if (INTEGERP (documentation) && XINT (documentation) < 0)
return Qt;
if (STRINGP (documentation)
&& ((unsigned char) SREF (documentation, 0) == '*'))
return Qt;
/* If it is (STRING . INTEGER), a negative integer means a user variable. */
if (CONSP (documentation)
&& STRINGP (XCAR (documentation))
&& INTEGERP (XCDR (documentation))
&& XINT (XCDR (documentation)) < 0)
return Qt;
/* Customizable? See `custom-variable-p'. */
if ((!NILP (Fget (variable, intern ("standard-value"))))
|| (!NILP (Fget (variable, intern ("custom-autoload")))))
return Qt;
return Qnil;
/* If indirect and there's an alias loop, don't check anything else. */
if (XSYMBOL (variable)->indirect_variable
&& NILP (internal_condition_case_1 (indirect_variable, variable,
Qt, user_variable_p_eh)))
return Qnil;
while (1)
{
documentation = Fget (variable, Qvariable_documentation);
if (INTEGERP (documentation) && XINT (documentation) < 0)
return Qt;
if (STRINGP (documentation)
&& ((unsigned char) SREF (documentation, 0) == '*'))
return Qt;
/* If it is (STRING . INTEGER), a negative integer means a user variable. */
if (CONSP (documentation)
&& STRINGP (XCAR (documentation))
&& INTEGERP (XCDR (documentation))
&& XINT (XCDR (documentation)) < 0)
return Qt;
/* Customizable? See `custom-variable-p'. */
if ((!NILP (Fget (variable, intern ("standard-value"))))
|| (!NILP (Fget (variable, intern ("custom-autoload")))))
return Qt;
if (!XSYMBOL (variable)->indirect_variable)
return Qnil;
/* An indirect variable? Let's follow the chain. */
variable = XSYMBOL (variable)->value;
}
}
DEFUN ("let*", FletX, SletX, 1, UNEVALLED, 0,
......
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