A rule is a useless chain iff it's a chain (aka unit, or injection)
rule (i.e., the RHS has length 1), and it's useless (it has no used
defined semantic action).
* src/gram.h, src/gram.c (rule_useless_chain_p): New.
(grammar_dump): Report useless chain rules.
* tests/sets.at: Check the traces.
There are several places where we need to recover the rule from an
item, let's factor that into item_rule. We also want to print items
in a nice way: we do it when generating the *output file, but it is
also useful in debug messages.
* src/gram.h, src/gram.c (item_rule, item_print): New.
* src/print.c (print_core): Use them.
* src/state.h, src/state.c: Propagate constness.
The memory allocated by 'closure' (and some data such as 'fderives')
is used to computed a state's full itemset from its core. This is
needed during the construction of the LR(0) automaton, and the memory
is reclaimed immediately afterwards.
Unfortunately the reports (graph, text, xml) also need this
information when describing the states with their full itemsets. As a
consequence the memory was allocated again, fderives computed again
too, and more --trace reports are generated which only duplicate what
was already reported.
Stop that. It does mean that we release the memory later (hence the
peak memory usage is higher now), but I don't think that's a problem
today.
* src/lr0.c (generate_states): Don't call closure_free.
* src/state.c (states_free): Do it here.
(for symmetry with closure_new which is called in generate_states).
* src/print-graph.c, src/print-xml.c, src/print.c: You can now expect
the closure module to be functional.
This is more consistent with the other files.
* closure.h, closure.c (new_closure, free_closure): Rename as...
(closure_new, closure_free): this.
Adjust dependencies.
This will make it easier to add new elements (that might already be
part of shift_symbol) without having to worry about the size of
shift_symbol (which is currently a fixed size vector).
I could not measure any significant differences in performances in the
generation of LR(0) automaton (benched on gramamrs of Ruby, C, and C++).
* src/lr0.c (shift_symbol): Make it a bitset.
When debugging Bison itself, this is very handy, especially when
tweaking the frontend badly enough to break the backends. It can also
be used to check a grammar.
* src/getargs.h, src/getargs.c (feature_syntax_only): New.
(feature_args, feature_types): Adjust.
* src/main.c (main): Use it.
* src/symtab.h (status): Rename as...
(declaration_status): this, to avoid colliding with status, the
argument of 'usage'.
'status' seems a tad too general to be used only here.
* maint:
maint: post-release administrivia
version 3.3.1
yacc: issue warnings, not errors, for Bison extensions
style: formatting changes in NEWS and complain.c
tests: don't depend on the user's definition of SHELL
* src/gram.c (grammar_dump): Print the effective number first instead
of last. And fix it (remove the incorrect "+1").
Use t/f for Booleans.
* src/reduce.c: When asked, always print the reduced grammar, even if
there was nothing useless.
* tests/sets.at (Reduced Grammar): Check that.
It is inconvenient that we also generate the output files when we
update the grammar file, and it's somewhat unexpected. Let's not do
that.
* src/main.c (main): Skip generation when --update is passed.
* src/getargs.c (usage): Update the help message.
* doc/bison.texi (Bison Options): Likewise.
* tests/input.at: Check that we don't generate the output.
After all, this is clearly harmless.
* src/muscle-tab.c (muscle_percent_define_insert): Let equal
definitions of a %define variable be only a warning.
Adjust test cases.
* tests/input.at ("%define" backward compatibility): Don't define
twice "api.namespace", so that we don't get an error, which stops the
process too soon to see an error about the value given to
'lr.keep-unreachable-state'.
Don't repeat the name of the warning in the sub messages. E.g.,
remove the second "[-Wother]" in the following message
foo.y:2.1-27: warning: %define variable 'parse.error' redefined [-Wother]
%define parse.error verbose
^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.y:1.1-27: previous definition [-Wother]
%define parse.error verbose
^~~~~~~~~~~~~~~~~~~~~~~~~~~
* src/complain.c (error_message): Don't print the warning type when
it's indented.
Adjust test cases.
Reported by Derek Clegg
http://lists.gnu.org/archive/html/bug-bison/2019-01/msg00021.html
aux/parser-internal.h:429:12: error: 'syntax_error' has no out-of-line virtual
method definitions; its vtable will be emitted in every translation unit
[-Werror,-Wweak-vtables]
struct syntax_error : std::runtime_error
To avoid this warning, we need syntax_error to have a virtual function
defined in a compilation unit. Let it be the destructor. To comply
with C++98, this dtor should be 'throw()'. Merely making YY_NOEXCEPT
be 'throw()' in C++98 triggers
errors (http://lists.gnu.org/archive/html/bug-bison/2019-01/msg00022.html),
so let's introduce YY_NOTHROW and flag only ~syntax_error with it.
Also, since we now have an explicit dtor, we need to provide an copy
ctor.
* configure.ac (warn_cxx): Add -Wweak-vtables.
* data/skeletons/c++.m4 (YY_NOTHROW): New.
(syntax_error): Declare the dtor, and define the copy ctor.
* data/skeletons/glr.cc, data/skeletons/lalr1.cc (~syntax_error):
Define.
