Computes the type of the expression given by node. The type of the node is computed in the context of the context of the supplied type enviro

var = 'a' ..context => Let('var' String('a'), context) var, z = 'a', 'b' ..c

Checks whether a given variable occurs in a list of non-generic variables Note that a variables in such a list may be instantiated to a type term

The main example program. Sets up some predefined types using the type constructors TypeVariable, TypeOperator and Function. Creates a list

sum of the numbers from 0 to n inclusively

Try to evaluate a type printing the result or reporting errors. Args: env: The type environment in which to evaluate the expression.

Names are allocated to TypeVariables lazily, so that only TypeVariables present

rewrite a + b as __add__(a, b) etc

rewrite compile-time decorators to annotations is_native

rewrite a == b as __eq__(a, b) etc

rewrite compile-time decorators to annotations native a_native, a flag specifying if the body should be visited or

rewrite not var as __not__(var) etc