Rename Dict[Var, TypeVar] to VarTyping; Add VarMap (Dict[Var,Var]). Add {Ast, Def, Rtl}.{vars(), substitution()} and Def.uses(), Def.definitions() - these enable checking structural equivalence between Rtls and doing variable substitutions between compatible Rtls; Add TypeEnv.permits() routine - allows checking if a given TypeEnv allows a given concrete typing without enumerating all typings (will be useful for determing which semantic transform applies to a given concrete typing).

lib/cretonne/meta/cdsl/instructions.py

@@ -7,14 +7,16 @@ from .formats import InstructionFormat
 
 try:
     from typing import Union, Sequence, List, Tuple, Any, TYPE_CHECKING  # noqa
+    from typing import Dict # noqa
     if TYPE_CHECKING:
-        from .ast import Expr, Apply  # noqa
+        from .ast import Expr, Apply, Var  # noqa
         from .typevar import TypeVar  # noqa
         from .ti import TypeConstraint  # noqa
         # List of operands for ins/outs:
         OpList = Union[Sequence[Operand], Operand]
         ConstrList = Union[Sequence[TypeConstraint], TypeConstraint]
         MaybeBoundInst = Union['Instruction', 'BoundInstruction']
+        VarTyping = Dict[Var, TypeVar]
 except ImportError:
     pass