Free variable smie--parent

[psteckler]

The file coq/coq-smie.el has a couple of references to free variable `smie--parent'.

I see that variable defined in some versions of smie.el online, but it's not in my installation. I'm running Emacs 24.3.1.

[cpitclaudel]

Are you sure? It dates back to 2010:

2010-10-29  Stefan Monnier  <monnier@iro.umontreal.ca>

    SMIE: change indent rules format, improve smie-setup.
    (...)
    (smie--parent, smie--after): New dynamic vars.

[psteckler]

I see the warning message when running make on the PG trunk.

I downloaded the .el source package for my Emacs, and yes, I see the defvar.

Maybe because the variable has not been assigned to? I don't know the
behavior of Elisp so well.

-- Paul

On Tue, May 10, 2016 at 4:27 PM, Clément Pit--Claudel <
notifications@github.com> wrote:

Are you sure? It dates back to 2010:

2010-10-29 Stefan Monnier monnier@iro.umontreal.ca

SMIE: change indent rules format, improve smie-setup.
(...)
(smie--parent, smie--after): New dynamic vars.

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#74 (comment)

[cpitclaudel]

Ah, I see :) Yup, I see the message as well. The trick is that smie--parent is a dynamic variable. See this:

defvar is a special form in ‘C source code’.

(defvar SYMBOL &optional INITVALUE DOCSTRING)

Define SYMBOL as a variable, and return SYMBOL.
You are not required to define a variable in order to use it, but
defining it lets you supply an initial value and documentation, which
can be referred to by the Emacs help facilities and other programming
tools.  The ‘defvar’ form also declares the variable as "special",
so that it is always dynamically bound even if ‘lexical-binding’ is t.

The warning is benign, but replicating the defvar form (with no initialization, of course) into the relevant PG source file would work (and is in fact the right way to do this).