Try using Convert python bytecode to Simple AST and using Stack Machine to simple type check

usage

from TVar import *
from check import T
@T
def sum( ilst : [Int] ) -> Int :
    if ilst == [ ]:
        return 0
    else:
        return ilst[0] + sum(ilst[1:])
"""
this example is right 
but next example is not right
"""

• bad usage:

  from TVar import *
  from check import T
  @T
  def sum( ilst : [Int] ) -> Int :
      if ilst == [ ]:
          return None
      else:
          return ilst[0] + sum(ilst[1:])
      

  • there will raise error

# when ilst is empty list then sum function return None , None in TVar is Unit ,
# but sum function __annotations__ return type is Int , so , will raise a Error of typecheck
# machine.CheckError: for return type(s): Int and Unit