Move/rename `LangkitRoot.fetch_prelude` to `LktNode.prelude_unit` so
that this property is easily available from all nodes and so that its
name is more "getter-like".
Also introduce the `LktNode.is_from_prelude` to simplify the codebase.
`LangkitRoot` nodes now define modules, so they must be treated as
declarations for these modules. This is necessary for the semantic
analysis to allow named references to Lkt modules.
This commit is a "backport" of the recent changes in the LKQL pattern
syntax to the lkt pattern syntax.
Unused features, deprecated constructs where removed and the parse-tree
was flattened to simplify lowering.
See langkit-query-language#597 and langkit-query-language#596 for more
details.
* Make the grammar less ambiguous by changing the syntax of the lexer's
forward declartion from `Foo` to `Foo <- null`
* This in turn allows the sharing of the `decl` grammar rule in the
grammar, simplifying the grammar and allowing the production of better
error messages.
* The lexer_decl rule is simplified (lexer_family_decl occured twice)
* GrammarNull is allowed to not have a type suffix
Introduce a new node (`BlockExprClause`) so that:
1. The `;` token belongs to list items in block expressions rather than
being a separator for that list.
2. The inner expression in block exprs belongs to that list, so that
there is no `;` token parser that follows the parser for that list.
The conjunction of both points allows us to introduce `skip`/`dont_skip`
parser for error recovery in the parsing of block expressions. The extra
sources that are accepted by the new parser are rejected by the Lkt
frontend.
Note that, due to a Langkit parser bug (likely
eng/libadalang/langkit#652), sometimes there is no parsing error even
though the parse tree contains an error node. This should be addressed
later.
``custom_image`` was calling ``full_name``, which was a public property:
this implies that PLE would be called when using simple syntaxic
methods, like ast dumping. This introduces ``full_name_internal`` which
is used internally instead of ``full_name``, which becomes a simple
public wrapper.
The first iteration was just a relatively basic copy&paste from the LKQL
grammar, that carries a lot of cruft and legacy at this stage. Following
the comments on the initial review for the merge request, it was decided
to take the opportunity to clean the grammar.
* Rename "BasePattern" into "Pattern"
* Remove every pattern abstract intermediate class (ValuePattern and
NodePattern). The categorizations they introduce is not very useful,
and they introduce a lot of complexity.
* Rename pattern details
* Remove mentions of "node" patterns, since we want to make the notion
of matching on a given type more general than just for node types.
* Rename ExtendedNodePattern -> ExtendedPattern, since we might want to
generalize the notion, and NodeKindPattern was renamed into
TypePattern already.
* Rewrite most of the docstrings
* Rename Splat -> Ellipsis
* Unify the naming of sub pattern fields (call them all
`sub_pattern`/`sub_patterns`.
Parse fields that contain list nodes or qualifier nodes are never
supposed to contain actual null nodes, but empty lists/absent qualifier
nodes instead. However, declaring null fields removes storage for them,
and thus makes the getters return null nodes in the generated libraries,
which is inconsistent.
Reject these null parse fields to avoid this inconsistency. Rework
Liblktlang and the `ada_api/rewriting` testcase to avoid this.
Keep track of whether some expression has null-conditional behavior with
`f_null_cond` fields (to note whether `?` is present) rather than
alternative subclasses (`DotExpr`/`NullCondDotExpr`,
`SubscriptExpr`/`NullCondSubscriptExpr`).
