Let primitive operators be normal function

[ENvironmentSet]

lambda2wasm has some primitive operators such as + and -. these are handled specially in type checker and code generator, but I hope them not to be, to reduce complexity of language and increase ease of adding other operations.

Here, I suggest to write module for handling syntactic sugars before type check process. this module will transform arithmetic operators and other structured expressions such as pattern matching, if-then-else into normal functions.