leanprover / leanprover/lean4

Statically associate precedence with parsers

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P-low refactoring
Dominant language
Lean
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Forks
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Avg merge
1d 17h
Merged PRs (30d)
175

Description

We noticed that we use non-initial checkPrecs only in two parsers: Type/Type u and Sort/Sort u. Arguably both of these should be split and checkPrec replaced with a precedence attribute parameter, which would simplify retrieving the precedence of a parser in both the pretty printer and the lhsPrec code.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Locate the definitions and uses of the Type/Type u and Sort/Sort u parsers, then trace checkPrec into the pretty printer and lhsPrec code. The refactor is complete when those parsers use precedence attribute parameters and precedence retrieval is simplified in both consumers.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Refactor
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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