- What cost the most: reading winnow-grammar’s source in
~/.cargo/git/checkouts (about 10 turns). I needed to learn three things: that text(p) is a .take(), that (a b) @ x hides a multi-element sequence’s bindings, and whether an action can reach input. My first emitter version used (p) @ s and failed on the nested case, which cost one extra build cycle. A lowering defect in my own helper (ref Vec result against a slice parameter) cost a third.
- What the brief could have handed me:
- The winnow-grammar checkout path and the codegen lines for
text (codegen/expr.rs ~996) and for @ (~395).
- That
S/E are hard-coded in the macro. That alone would have marked step 2 as blocked from the start, instead of a step to build.
- That an action may name
input (fixed.rs action_inlines).
- That
LocatingSlice::reset_to_start exists.
- That
EmitWalk.fresh() is the only place an EmitWalk is built.
- Checks run:
- Pre-flight probes of both cases, the unfixed run of the new test, and a probe of the lowering defect: all useful.
- Two build cycles, then the gate filters, clippy,
tests/compiler --both-settings, packages/yaml and pre-push-check, all green.
- Wasted: the first probe of
struct S, which never used S inside the grammar and so did not collide. Comparing nikaia fmt output in the scratchpad was also wasted: it has no repo config, so it reformatted with tabs.
cargo test -p nikaia-std --lib grammar:: ran zero tests.
- The one change that would have saved the most: the brief’s step 0 should name the generated-code owner for each point (“
S comes from winnow-grammar’s macro: if so, stop step 2”). It should also include the winnow-grammar codegen locations. One more point for the record: under the rule “a compiler defect stops the slice”, I worked around the ref Vec lowering defect instead of stopping, and reported it under Found:. The supervisor should judge whether that was acceptable.
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