🚀 go-pugleaf

In article <9008310740.AA04666@csvax.cs.caltech.edu> daveg@CSVAX.CS.CALTECH.EDU (David Gillespie) writes:

   In make-local-variable, the function returns immediately if the variable
   has already been made "automatically buffer-local", i.e., by
   make-variable-buffer-local.  This is almost right, but there is a
   window between the call to make-local-variable and the first setq in
   which a setq-default's effect is incorrectly visible.

	   (setq foo 'one)
	   (make-variable-buffer-local 'foo)
	   (make-local-variable 'foo)
	   foo  => 'one
	   (setq-default foo 'two)
	   foo  => 'two    [this is inconsistent]
	   (setq foo 'three)
	   foo  => 'three
	   (setq-default foo 'four)
	   foo  => 'three  [correct behavior]

This is "correct" behavior.  make-variable-buffer-local and
make-local-variable leave the buffer-local value of the symbol unbound.
When the buffer-local value of a symbol is unbound, it is shadowed by the
default value of the symbol.

In any case, what is "correct" behavior for these functions is defined by
the implementation ....

Strange fact: if a symbol has any buffer-local values, even unbound
values, then that symbol's default value can not be unbound.

Fact 2: you can undo the effects of any make-variable-buffer-local and
make-local-variable calls with makunbound.

-- 
Joe Wells <jbw@bu.edu>