leanprover / leanprover/reference-manual
Improve description of `grind_pattern`
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Description
What question should the reference manual answer?
This feedback was provided on Zulip:
I'm finally getting around to reading about grind in the reference manual. In 17.6.1 the introduction of grind_pattern gf => f x is done in a sort of matter-of-fact way, but its not clear (a) what exactly that does, or (b) why that suddenly causes grind to be able to solve the goal. The lead up to that motivates the move by explaining that the base gf rule doesn't fire (at least in part) because "the goal does not even contain the function symbol g", but the goal doesn't contain f either.
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Research direction
Start by reading section 17.6.1 of the reference manual and the linked Zulip discussion. Clarify what the grind_pattern gf => f x pattern does and why it lets grind solve the goal, especially given that the goal contains neither g nor f. Done means the example's motivation and behavior are understandable from the manual alone.
Written by the indexing model from the issue text.
Assessment
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 52/100