leanprover / leanprover/lean4

suffices syntax could be made more uniform with other tactics

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#2,520 4 comments 4 reactions 0 assignees View on GitHub

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low priority P-low RFC
Dominant language
Lean
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Description

Currently suffices has its own syntax, either suffices h : t from x or suffices h : t by tac. This feels like a Lean3-ism, and it would be better to be consistent with other tactics and require instead suffices h : t := x or suffices h : t := by tac.

Prompted by a suggestion from @sgouezel.

It is possibly simply too late to change this, but for now I will leave this here marked as low priority to see what people think.

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Research direction

Review the existing suffices syntax and compare it with the other tactics whose syntax it should match. Verify the accepted from, by, and proposed := forms, then check that the change is consistent across parser behavior and relevant syntax tests. Done means the proposed forms work and the old forms are handled as intended.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Refactor
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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