407a59d697
This PR modifies the pretty printing of pi types. Now `∀` will be preferred over `→` for propositions if the domain is not a proposition. For example, `∀ (n : Nat), True` pretty prints as `∀ (n : Nat), True` rather than as `Nat → True`. There is also now an option `pp.foralls` (default true) that when false disables using `∀` at all, for pedagogical purposes. This PR also adjusts instance implicit binder pretty printing — nondependent pi types won't show the instance binder name. Closes #1834. The linked RFC also suggests using `_` for binder names in case of non-dependance. We're tabling that idea. Potentially it is useful for hygienic names; this could improve how `Nat → True` pretty prints as `∀ (a : Nat), True`, with this `a` that's chosen by implication notation elaboration. Relatedly, this PR exposes even further the issue where binder names are reused in a confusing way. Consider: `Nat → Nat → (a : Nat) → a = a` pretty prints as `∀ (a a a : Nat), a = a`.
21 lines
255 B
Text
21 lines
255 B
Text
1682.lean:1:25-2:17: error: unsolved goals
|
|
case a
|
|
p : Sort u_1
|
|
q r : Prop
|
|
⊢ ∀ (a : p), q
|
|
|
|
case b
|
|
p : Sort u_1
|
|
q r : Prop
|
|
⊢ r
|
|
1682.lean:4:25-5:26: error: unsolved goals
|
|
case a
|
|
p : Sort u_1
|
|
q r : Prop
|
|
h : p
|
|
⊢ q
|
|
|
|
case b
|
|
p : Sort u_1
|
|
q r : Prop
|
|
⊢ r
|