Introduce function types.

Function types are just functions from types to check-results. Nothing more than
delayed computation. Efficiency will initially be no better than current.
Caching results could help, but that's a future problem.

An alternative approach is introducing constraints. That would be a bigger
architectural change, with more complex processing. On the other hand, adding
future extensions would be easier.

1 files changed, 1 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 0d48eb1..7e2197b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ members = ["autochomp", "chewed", "chomp-bench", "chomp-macro"]
 
 [dependencies]
 heck = "0.3.2"
+once_cell = "1.7.2"
 proc-macro2 = "1.0.24"
 quote = "1.0.8"
 syn = "1.0.58"