Ludovic Courtès (2015-10-17 16:34 +0300) wrote: > Alex Kost <[email protected]> skribis: > >> From dd793147718cb18766268c8aad50d24b88ffe6b6 Mon Sep 17 00:00:00 2001 >> From: Alex Kost <[email protected]> >> Date: Fri, 16 Oct 2015 20:34:32 +0300 >> Subject: [PATCH 1/2] build: Set DOT_USER_PROGRAM for Emacs interface. >> MIME-Version: 1.0 >> Content-Type: text/plain; charset=UTF-8 >> Content-Transfer-Encoding: 8bit >> >> Suggested by Ludovic Courtès <[email protected]>. >> >> * configure.ac: Set DOT_USER_PROGRAM variable. >> * emacs/guix-config.el.in (guix-config-dot-program): New constant. >> * emacs/guix-external.el (guix-dot-program): Use it. > > [...] > >> +(defconst guix-config-dot-program "@DOT_USER_PROGRAM@" >> + "Name of the 'dot' executable defined at the configure time.") > > “at configure time”
Thanks. > The docstring should mention that it can be the empty string. > Alternately, ‘configure’ could set DOT_USER_PROGRAM to “dot” when it’s > not found, which I think is ever preferable. WDYT? IMO an empty string is preferable (explained below), so I would like to leave it like this (with an improved docstring as you pointed), if you don't mind. >> +(defcustom guix-dot-program >> + (if (string= "" guix-config-dot-program) >> + (executable-find "dot") >> + guix-config-dot-program) > > Thus here we’d be checking whether ‘guix-config-dot-program’ is an > absolute file name. I think (executable-find "dot") is more reliable than just "dot" which may not exist. So if there is no "dot" program, then ‘guix-dot-program’ variable will be set to nil. And once "dot" will be needed, a user will get a useful (I hope) emacs error that "dot" is missing (it is handled by ‘guix-dot-arguments’ function). While with just "dot" as you suggest, there will be some unpleasant error in Guix REPL (it will happen in ‘pipe-guix-output’ proc in “emacs/guix-main.scm”). -- Alex
