Leonardo de Moura 0b7d987699 feat(frontends/lean, library/init/lean): opaque constants ... @kha I have added support for opaque constants to the old C++ frontend, and made sure the new frontend can still parse `library/init/core.lean`. The kernel should enforce that opaque constants are really opaque, and the following example should fail ``` constant x : nat := 0 theorem foo : x = 0 := rfl ``` If it doesn't, it is a bug. Here are some remaining issues: 1- `environment.mk_empty` is currently an axiom because we cannot create an inhabitant of an opaque type. A possible solution is to use `option environment` instead of `environment`. 2- There is no support for opaque constants in the new frontend. However, I modified it to handle axioms, and fixed the literal values with decl_cmd_kind. I tried to mark some of my changes with comments, but it is probably much easier for you to just check the commit change list. 3- I did not add any support for automatically constructing `e` at `constant x : t := e`. I think we can do this later after we replace the old frontend with the new one. BTW, it took only a few minutes to provide the inhabitants manually.		2019-03-15 17:41:44 -07:00
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basic.lean	feat(frontends/lean, library/init/lean): opaque constants	2019-03-15 17:41:44 -07:00
default.lean	chore(*): remove more files	2018-05-21 06:42:58 -07:00