Re: RFC: build: be robust to missing flex

[Akim Demaille]

Le 27 mars 2012 à 15:43, Akim Demaille a écrit :

>>> +if `$LEX --version` 2>/dev/null | grep flex; then
>>> 
>> Spurious command substitution here?
> 
> *blush*...

Actually there are other issues.  One is that $missing_dir,
documented by Autoconf, does not seem to exist.  Automake
says nothing about missing's location.  Reading configure,
$MISSING seems to be what I am looking for, but maybe
after all I could just really require flex and stop bothering
with missing.  I was reluctant to this move because historically
Bison did not require it, but on second thought it was wrong.

So that would be the updated proposal.

From af673933e403f380954c3f726079e3273b837b83 Mon Sep 17 00:00:00 2001
From: Akim Demaille <address@hidden>
Date: Tue, 27 Mar 2012 08:22:49 +0200
Subject: [PATCH] build: require flex.

Since the generated files are included in the tarball, it is
not strictly needed.  Yet if the user touches the flex source
files, the builds do not propagate the changes properly.

Besides, the examples now uses flex on the user side, and it
seems better to require flex rather than degrading the way the
package builds itself.

With help from Stefano Lattarini.
* configure.ac: We need flex to build bison, lex does not suffice.
* examples/calc++/local.mk: Comment changes.
---
 configure.ac             |    3 +++
 examples/calc++/local.mk |    2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 622da5d..5c97683 100644
--- a/configure.ac
+++ b/configure.ac
@@ -110,6 +110,9 @@ AC_SUBST([YACC_LIBRARY])
 
 # Checks for programs.
 AC_PROG_LEX
+if $LEX --version 2>/dev/null | $EGREP 'f?lex 2\.5\.3' >/dev/null; then :; else
+  AC_MSG_ERROR([flex 2.5.3* is required])
+fi
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4
diff --git a/examples/calc++/local.mk b/examples/calc++/local.mk
index 16f49c4..d426f7d 100644
--- a/examples/calc++/local.mk
+++ b/examples/calc++/local.mk
@@ -70,4 +70,4 @@ nodist_examples_calc___calc___SOURCES =               \
 
 examples_calc___calc___CPPFLAGS = -I$(top_builddir)/examples/calc++
 dist_TESTS += examples/calc++/calc++.test
-endif
+endif BISON_CXX_WORKS
-- 
1.7.9.4