Cleans up a few places where we were constructing trees piece by piece
rather than using the `tree!` macro.
In the process, Copilot noticed an issue that should probably be
addressed: the labeled_statement rule can never fire, since there are no
such nodes in the input. This is possibly a simple as making
_labeled_statement (which _does_ exist) named, but I haven't attempted
this.
Finally, a small change to yeast makes it so that the contents of a {}
interpolation can be a Rust block (previously it could only be a single
expression). This avoids the need to double-wrap instances where you
want to interpolate a single node produced as the final value of some
block.
(Both reduce_left and map are still supported, but we could remove them
at this point.)
I think this way of writing things makes the intent a lot clearer -- it
avoids extending the yeast rule language with complicated constructs,
pushing the complexity (such as it is) into Rust instead.
Gets rid of the final uses of mutation (via prepend_field). The approach
is the same as in the preceding commits: we set the appropriate fields
on the context when processing the outer node, and then access these
fields on the inner nodes.
The repeated use of `modifier` fields is a _bit_ clunky, but since we're
likely moving to an out-of-band modifier mechanism at some point, I
think it's good enough for now.
Avoids more "mutation after creation" via prepend_field.
Also adds a test to the corpus for exercising this syntax. Although it's
not evident, the test output was unchanged by this refactoring.
Extends the context with a field for keeping track of the default value.
In the process, we also rename the context to SwiftContext as it now
doesn't only concern itself with properties.
Propagates in name and type information for various property
declarations, using the context mechanism. This avoids mutating
already-translated nodes in-place, and is generally much easier to read.
This was necessary since otherwise the generic type of the
user-specified context (which should only be a concern for yeast) starts
to bleed out into the shared extractor. Instead, we type-erase it by
putting it inside the aforementioned trait.
Adds `manual_rule!` which provides a more low-level interface for
defining rewrites. (I'm not entirely sold on the name, so any
suggestions would be welcome.)
Notably, the captures bound in the body of such rules have _not_ been
translated yet -- they still come from the _input_ tree. It is the
user's duty to call ctx.translate on these (which has the effect of
recursively invoking the translation) before substituting them into the
output.
For _truly_ low-level access, the user can still construct a Rule
directly, but this is now somewhat cumbersome as the closure contained
therein takes quite a few parameters. Still, the possibility remains.
This enables users to specify how and when these captures get
translated. In conjunction with the context mechanism, this can be used
to e.g. translate some piece of information (e.g. the type of
something), record it in the context, and then recursively translate
some other capture that relies on this information. This allows
information to be cleanly passed into descendants (which can be written
using context accesses in the `rule!` macro form).
As a consequence of this change, we now need to pass around a
TranslatorHandle to perform the manual translation. For Repeating rules,
it doesn't really make sense to translate things, so in this case we
simply signal an error.
Also, the implementation of the `rule!` macro changes slightly (without
changing semantics): it now essentially delegates to `Rule::new`,
receiving raw captures, but then immediately applies the translation to
those captures (which, for the majority of cases, is likely the desired
behaviour).
Renames what was previously called `__yeast_ctx` into just `ctx`, and
adds a new field `user_ctx` to this context. Said field can contain a
struct of any user type (necessitating making various parts of the
implementation generic in said type).
Through some Deref magic, field accesses are delegated to the inner
struct (assuming they are not already defined on `ctx`), which should
hopefully make the interface a bit more ergonomic.
Patterns have an unusual parse tree, but now the matching should
at least be a bit easier to follow.
The TODO regarding not being able to pass down context to handle
var/let is still relevant, and can't be solved in the mapping alone.
Adds a test case 'Switch with labeled case pattern arguments' covering:
- case .implicit(isAcknowledged: false) — labeled bool literal
- case .thread(threadRowId: _, let rowId) — labeled wildcard + binding
The current output contains type errors: pattern_element::key is being
produced as name_expr instead of identifier. These will be fixed in the
following commit.
The switch_entry rule was capturing switch_pattern wrapper nodes instead of
drilling into them to extract the actual pattern nodes. This caused patterns
from switch cases to be lost during desugaring.
Changed the pattern match from:
(switch_entry pattern: (switch_pattern)* @pats ...)
to:
(switch_entry pattern: (switch_pattern pattern: @pats)* ...)
This now correctly extracts the pattern field from each switch_pattern node,
ensuring that patterns from cases like 'case 1:' and 'case .circle(let r):'
are preserved in the switch_case AST nodes.
Updated control-flow.txt corpus outputs to reflect the new behavior.
Previously, when a node was synthesized it would always take the
location from the node that matched the current rule. This resulted
in overly broad locations however.
For (foo #{bar}) we now take the location of the 'bar' node.
For non-leaf nodes we merge all its child node locations.
When a field pattern has a bare capture with no preceding pattern
atom (i.e. `foo: @bar`), implicitly use a true wildcard (`_`,
match_unnamed: true) as the node pattern, making it equivalent to
`foo: _ @bar`.
This is a convenience shorthand: in practice every `field: _ @cap`
in the Swift rules can now be written more concisely as `field: @cap`.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
A left fold over an iterable where the first element seeds the accumulator:
- first -> init : converts the first element to the initial accumulator
- acc, elem -> fold : fold step; acc = current accumulator, elem = next element
- Empty iterable produces nothing (0-element splice)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
After a {expr} or {..expr} placeholder, an optional chain of
.<builtin>() calls may follow. Currently the only builtin is:
.map(param -> template)
which applies the template to each element of the iterable and
collects the resulting node IDs. A chain auto-splices into the
enclosing field/child position.
Example:
path: {parts}.map(p -> (identifier #{p}))
The framework is extensible: additional builtins can be added by
matching on the method name in parse_chain_suffix.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
