问题
How can we get the definition/type for those notations like "+", or "++" of List?
I have tried : Search ++, Search "++", Search (++),
SearchAbout ... and
Check ++, Check "++", Check(++).
None of them work however...
SearchAbout "++" does show some info, but not the definition of "++".
回答1:
Do:
Locate "++".
To lookup for notations.
Then you can Print/Check the actual term being denoted.
回答2:
In addition to previous answer, you can use Unfold "++" to unfold it's definition without locating it first.
Example:
Coq < Goal forall A (l : list A), l ++ [] = [].
1 subgoal
============================
forall (A : Type) (l : list A), l ++ [] = []
Unnamed_thm < unfold "++".
1 subgoal
============================
forall (A : Type) (l : list A),
(fix app (l0 m : list A) {struct l0} : list A :=
match l0 with
| [] => m
| a :: l1 => a :: app l1 m
end) l [] = []
来源：https://stackoverflow.com/questions/26029594/find-the-definition-and-notations-like-in-coq