Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
f63ddd67a2
This PR adds `simpControl`, a simproc that handles control-flow expressions such as `if-then-else`. It simplifies conditions while avoiding unnecessary work on branches that won't be taken. The key behavior of `simpControl`: - Simplifies the condition of `if-then-else` expressions - If the condition reduces to `True` or `False`, returns the appropriate branch, and continue simplifying. - If the condition simplifies to a new expression, rebuilds the `if-then-else` with the simplified condition (synthesizing a new `Decidable` instance), and mark it as "done". That is, simplifier main loop will not visit branches. - Does **not** visit branches unless the condition becomes `True` or `False` This is useful for symbolic simplification where we want to avoid wasting effort simplifying branches that may be eliminated after the condition is resolved. This PR also fixes a bug in `Sym/Simp/EvalGround.lean`, and adds some helper functions. |
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