Now that distcheck no longer fails (see previous commit), let's
address the shortcomings.
* Makefile.am (CLEANDIRS, clean-local): New.
* doc/local.mk, examples/calc++/local.mk, examples/local.mk,
* examples/mfcalc/local.mk, examples/rpcalc/local.mk,
* src/local.mk
(CLEANDIRS): Get rid of Apple's *.dSYM directories.
(CLEANFILES): Get rid of *.output files.
* examples/variant-11.yy, examples/variant.yy: Don't generate
any of the auxiliary files (location.hh and the like).
Modern C++ (i.e., C++11 and later) introduced "move only" types: types such
as std::unique_ptr<T> that can never be duplicated. They must never be
copied (by assignments and constructors), they must be "moved". The
implementation of lalr1.cc used to copy symbols (including their semantic
values). This commit ensures that values are only moved in modern C++, yet
remain compatible with C++98/C++03.
Suggested by Frank Heckenbach, who provided a full implementation on
top of C++17's std::variant.
See http://lists.gnu.org/archive/html/bug-bison/2018-03/msg00002.html,
and https://lists.gnu.org/archive/html/bison-patches/2018-04/msg00002.html.
Symbols (terminal/non terminal) are handled by several functions that used
to take const-refs, which resulted eventually in a copy pushed on the stack.
With modern C++ (C++11 and later) the callers must use std::move, and the
callees must take their arguments as rvalue refs (foo&&). In order to avoid
duplicating these functions to support both legacy C++ and modern C++, let's
introduce macros (YY_MOVE, YY_RVREF, etc.) that rely on copy-semantics for
C++98/03, and move-semantics for modern C++.
That's easy for inner types, when the parser's functions pass arguments to
each other. Functions facing the user (make_NUMBER, make_STRING, etc.)
should support both rvalue-refs (for instance to support move-only types:
make_INT (std::make_unique<int> (1))), and lvalue-refs (so that we can pass
a variable: make_INT (my_int)). To avoid the multiplication of the
signatures (there is also the location), let's take the argument by value.
See:
https://lists.gnu.org/archive/html/bison-patches/2018-09/msg00024.html.
* data/c++.m4 (b4_cxx_portability): New.
(basic_symbol): In C++11, replace copy-ctors with move-ctors.
In C++11, replace copies with moves.
* data/lalr1.cc (stack_symbol_type, yypush_): Likewise.
Use YY_MOVE to avoid useless copies.
* data/variant.hh (variant): Support move-semantics.
(make_SYMBOL): In C++11, in order to support both read-only lvalues,
and rvalues, take the argument as a copy.
* data/stack.hh (yypush_): Use rvalue-refs in C++11.
* tests/c++.at: Use move semantics.
* tests/headers.at: Adjust to the new macros (YY_MOVE, etc.).
* configure.ac (CXX98_CXXFLAGS, CXX11_CXXFLAGS, CXX14_CXXFLAGS)
(CXX17_CXXFLAGS, ENABLE_CXX11): New.
* tests/atlocal.in: Receive them.
* examples/variant.yy: Don't define things in std.
* examples/variant-11.test, examples/variant-11.yy: New.
Check the support of move-only types.
* examples/README, examples/local.mk: Adjust.
Currently the examples are too dense, let's put empty lines where
'#line' would be issued. And also remove some spurious empty
lines (remains from @group, @end group, etc.).
* examples/extexi: Do that.
* examples/local.mk (extexiFLAGS): Rename as...
(EXTEXIFLAGS): this.
* examples/mfcalc/local.mk, examples/rpcalc/local.mk: Define the
programs in a more natural order, source, preproc, then linker.
* examples/test: Be ready to work on programs that are not in
a subdir.
* examples/variant.test: New.
* examples/local.mk: Use it.
* examples/variant.yy: Don't use 0 for nullptr.
Use a more natural output for a list of string.
This file was meant to be shown as an example. Install it.
* README, data/README: Put Emacs metadata in the final section.
* examples/README: New.
* examples/variant.yy: Use %empty.
* examples/local.mk: Install both these files.
Currently, we do not install the various examples extracted from the
documentation. Let's do it, as they are useful starting points.
* configure.ac: When --enable-gcc-warnings is set, enable ENABLE_GCC_WARNINGS.
* examples/extexi: No longer issue synclines by default.
* examples/local.mk: Except if ENABLE_GCC_WARNINGS.
* examples/calc++/local.mk, examples/mfcalc/local.mk,
* examples/rpcalc/local.mk: Install the example files.
This is based on what is recommended by both Scott Meyers, in 'Effective
C++', and Andrei Alexandrescu and Herb Sutter in 'C++ Coding Standards'.
Use a static_cast on void* rather than directly use a reinterpret_cast,
which can have nefarious effects on objects. However, even though following
this guideline is good practice in general, I am not quite sure how relevant
it is when applied to conversions from POD to objects. Actually, it might
very well be the opposite: isn't this exactly what reinterpret_cast is for?
What we really want *is* to transmit the memory map as a series of bytes,
which, if I am correct, falls into the kind of "low level" hack for which
this cast is meant.
In any case, this silences the warning, which will be greatly appreciated by
anyone using variants with a compiler supporting -fstrict-aliasing.
* data/variant.hh (as): Here.
* tests/c++.at (Exception safety, C++ Variant-based Symbols, Variants):
Don't use NO_STRICT_ALIAS_CXXFLAGS (revert commit ddb9db15), as type punning
is no longer an issue.
* tests/atlocal.in, configure.ac (NO_STRICT_ALIAS_CXXFLAGS): Remove
definition.
* examples/local.mk (NO_STRICT_ALIAS_CXXFLAGS): Remove from AM_CXXFLAGS.
* doc/bison.texi: Don't mention type punning issues.
Bison uses "/usr/bin/perl" or "perl" in several places, and it does
not appear to be a problem. But, at least to make it simpler to
change PERL on the make command line, check for perl in configure.
* configure.ac (PERL): New.
* doc/Doxyfile.in, doc/local.mk, examples/local.mk,
* tests/bison.in: Use it.
calc++: don't rely on Automake to compile a C++ parser.
Basically, revert commit 609b3d8096,
Automake 1.11.3 is not safe enough for C++ parser.
* examples/calc++/calc++-parser.hh: Remove.
* examples/calc++/local.mk (examples/calc++/calc++-parser.stamp):
New.
examples: factor the extractions into a single step
extexi had to be run in the extraction directory. Now, it can be
given the files with expected output directory. This allows to
use $(*_extracted) variables (before we had to list again their
members, but limited to their base names). In turn, this also
allows fusing the extraction recipes into a single one.
Also, it is currently too hard (or requires too much duplication,
since Make wants all the occurrences of the files to be prefixed with
$(srcdir)/, which is something Automake cannot support for *_SOURCES)
to work in the source tree. So extract, and compile scanners and parsers
in the build tree.
* examples/extexi (basename): New.
(BEGIN): Now "file_wanted" maps base name to extracted file name.
* examples/calc++/local.mk, examples/mfcalc/local.mk,
* examples/rpcalc/local.mk: Fuse extraction rules into...
* examples/local.mk: Here.
(extract, extracted): New.
* examples/mfcalc/test, examples/calc++/test: Extract the
common bits into...
* examples/test: here.
(cwd): New.
Use it to avoid a race on the temporary directory.
Reported by Jim Meyering.
* examples/mfcalc/test, examples/calc++/test: Rename into...
* examples/mfcalc/mfcalc.test, examples/calc++/calc++.test: these.
* examples/calc++/local.mk, examples/mfcalc/local.mk,
* examples/local.mk: Adjust.
* Makefile.am (TESTS, check_PROGRAMS): Initialize here.
* examples/local.mk (doc, extexi): Define here.
* examples/calc++/local.mk: Adjust accordingly.
* configure.ac: Ask for parallel-tests (for the way the logs
are handled).
* examples/calc++/test: As a consequence, always be verbose.
($prog): New.
(run): Use it.
Sort the tests in a more natural order (simplest first).
The directory was still using a local Makefile.am because it provides
"scoped" Make variables: these examples are not meant to use the same
CPPFLAGS etc. If we were to use the same -I set, we'd pick up
gnulib's stdio.h for instance, which we do not want for these simple
examples.
Yet, as a result, the dependencies are less accurate, there is code
duplication, etc. This is especially perceptible when trying to
extract more examples from the documentation, as will be done in
forthcoming changes.
In order to make the tuning of CPPFLAGS easier, discard the predefined
-I from Automake.
* examples/calc++/Makefile.am: Rename as...
* examples/calc++/local.mk: this.
Adjust the paths which are now rooted in top_srcdir/top_builddir.
Handle BISON_CXX_WORKS here, instead of the too crude previous
approach that completely discarded the whole directory.
($(BISON)): Remove now useless bouncing recipe.
(calc___CPPFLAGS): New.
Stay away from -Ilib.
* Makefile.am, configure.ac, examples/local.mk,
* examples/calc++/test: Adjust.
* configure.ac: Pass nostdinc to Automake.
* src/local.mk, lib/local.mk (AM_CPPFLAGS): Move to...
* Makefile.am: here.
* src/local.mk, examples/calc++/Makefile.am (BISON, BISON_IN): Factor
to...
* Makefile.am: here.
* tests/local.mk: Use it.
examples/calc++/Makefile.am might be interesting to keep as is, since
it is an example in itself.
* examples/Makefile.am: Rename as...
* examples/local.mk: this.
Adjust.
* Makefile.am, configure.ac: Adjust.
