chore: prefer · == a over a == ·
#3056
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
github-actions
bot
added
the
toolchain-available
|
kim-em
force-pushed
the
swap_List.elem
branch
from
641d5e0 to
bf60bb6
Compare
leanprover-community-mathlib4-bot
added a commit
to leanprover-community/batteries
that referenced
this pull request
Jun 14, 2024
leanprover-community-mathlib4-bot
added a commit
to leanprover-community/mathlib4
that referenced
this pull request
Jun 14, 2024
leanprover-community-mathlib4-bot
added
the
builds-mathlib
github-merge-queue bot
pushed a commit
that referenced
this pull request
Jul 17, 2024
The previous argument order was a conscious choice, but I had missed #3056.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
We recently discovered inconsistencies in Mathlib and Std over the ordering of the arguments for
==.The most common usage puts the "more variable" term on the LHS, and the "more constant" term on the RHS, however there are plenty of exceptions, and they cause unnecessary pain when switching (particularly, sometimes requiring otherwise unneeded
LawfulBEqhypotheses).This convention is consistent with the (obvious) preference for
x == 0over0 == xwhen one term is a literal.We recently updated Std to use this convention leanprover-community/batteries#430
This PR changes the two major places in Lean that use the opposite convention, and adds a suggestion to the docstring for
BEqabout the preferred convention.