f36fca875c
Comment from parser.h
This commit makes sure that all declaration parameters must be surrounded with some kind of bracket. (e.g., '()', '{}', '[]').
The goal is to avoid counter-intuitive declarations such as:
example p : false := trivial
def main proof : false := trivial
which would be parsed as
example (p : false) : _ := trivial
def main (proof : false) : _ := trivial
where `_` in both cases is elaborated into `true`. This issue was raised by @gebner in the slack channel.
Remark: we still want implicit delimiters for lambda/pi expressions. That is, we want to write
fun x : t, s
or
fun x, s
instead of
fun (x : t), s
38 lines
1.1 KiB
Text
38 lines
1.1 KiB
Text
open nat
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inductive type : Type
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| Nat : type
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| Func : type → type → type
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open type
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section var
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variable {var : type → Type}
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inductive term : type → Type
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| Var : ∀ {t}, var t → term t
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| Const : nat → term Nat
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| Plus : term Nat → term Nat → term Nat
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| Abs : ∀ {dom ran}, (var dom → term ran) → term (Func dom ran)
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| App : ∀ {dom ran}, term (Func dom ran) → term dom → term ran
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| Let : ∀ {t1 t2}, term t1 → (var t1 → term t2) → term t2
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end var
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open term
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definition Term (t) := Π (var : type → Type), @term var t
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open unit
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definition count_vars : Π {t : type}, @term (λ x, unit) t -> nat
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| A (Var x) := 1
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| Nat (Const x) := 0
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| Nat (Plus e1 e2) := count_vars e1 + count_vars e2
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| (Func A B) (Abs e1) := count_vars (e1 star)
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| B (@App ._ A .(B) e1 e2) := count_vars e1 + count_vars e2
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| B (@Let ._ A .(B) e1 e2) := count_vars e1 + count_vars (e2 star)
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definition var (t : type) : @term (λ x, unit) t :=
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Var star
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example : count_vars (App (App (var (Func Nat (Func Nat Nat))) (var Nat)) (var Nat)) = 3 :=
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rfl
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