Rework the formatting for the listing of optional passes, refactor the
handling of --pass-on/--pass-off (to enable/disable optional passes), fix
a couple of crashes and add a testcase to exercise this little used part
of Langkit.
Whether or not case insensitivity should be enabled is tied to the
language itself, so this setting belongs to the language specification
better than to a CompileCtx argument.
Whether unparsers are generated or not has implications on legality
checks for the grammar, so it makes sense for this to be a property of
the grammar itself: introduce an Lkt annotation as well as a
langkit.parsers.Grammar argument for it, and remove the corresponding
CompileCtx argument.
Also rename "generate_unparser" to "generate_unparsers" for consistency
across the codebase.
Avoding this will allow lkt_compile/lkt_build_and_run tests to inspect
the compile context of Libfoolang from their "test.py" script, allowing
more "python" tests to transition to these drivers.
Transition all relevant testcases to it. In the process, port
docstrings/comments from test.py files to expected_concrete_syntax.lkt
(now test.lkt) sources and fix stylechecks issues there.
This makes the convention consistent with the DSL, and avoids
workarounds for conflicts with Lkt keywords: in Libadalang, the Null
token can stay Null, instead of null_tok (no API breakage needed).
This change enhances the unparsing engine so that template instantiation
keeps track of tokens from the source code to reformat as the unparsed
token are produced.
This is preparatory work to preserve formatting information from the
original source code (empty lines and comments), but no change of
behavior is expected at this stage.
Whether to generate unparsers or not has non-trivial implications on the
language spec. For this reason, it does not make much sense to keep this
setting as a code generation option: it should instead be a property of
the language spec itself.
