syntax: better internal VariableContex stype handling

Remove the sublcass CastVariableContex.
Add the method VariableContext::stype=

Current client does not need to be updated.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/syntax/control_flow.nit b/src/syntax/control_flow.nit
index ceadd4e..2eddf2c 100644 (file)
--- a/src/syntax/control_flow.nit
+++ b/src/syntax/control_flow.nit
@@ -66,7 +66,18 @@ abstract class VariableContext
        # May be different from the declaration static type
        meth stype(v: Variable): MMType
        do
-               return v.stype
+               if _stypes.has_key(v) then
+                       return _stypes[v]
+               else
+                       return v.stype
+               end
+       end
+
+       # Set effective static type of a given variable
+       # May be different from the declaration static type
+       meth stype=(v: Variable, t: MMType)
+       do
+               _stypes[v] = t
        end
 
        # Variables by name (in the current context only)
@@ -75,6 +86,9 @@ abstract class VariableContext
        # All variables in all contextes
        attr _all_variables: Set[Variable]
 
+       # Updated static type of variables
+       attr _stypes: Map[Variable, MMType] = new HashMap[Variable, MMType]
+
        # Build a new VariableContext
        meth sub(node: PNode): SubVariableContext
        do
@@ -84,7 +98,9 @@ abstract class VariableContext
        # Build a nested VariableContext with new variable information
        meth sub_with(node: PNode, v: Variable, t: MMType): SubVariableContext
        do
-               return new CastVariableContext.with_prev(self, node, v, t)
+               var ctx = sub(node)
+               ctx.stype(v) = t
+               return ctx
        end
 
        # The visitor of the context (used to display error)
@@ -171,7 +187,11 @@ special VariableContext
 
        redef meth stype(v)
        do
-               return prev.stype(v)
+               if _stypes.has_key(v) then
+                       return _stypes[v]
+               else
+                       return prev.stype(v)
+               end
        end
 
        init with_prev(p: VariableContext, node: PNode)
@@ -187,27 +207,6 @@ special VariableContext
        end
 end
 
-class CastVariableContext
-special SubVariableContext
-       attr _variable: Variable
-       attr _var_type: MMType
-
-       redef meth stype(v)
-       do
-               if _variable == v then
-                       return _var_type
-               end
-               return prev.stype(v)
-       end
-
-       init with_prev(p: VariableContext, node: PNode, v: Variable, t: MMType)
-       do
-               super(p, node)
-               _variable = v
-               _var_type =t
-       end
-end
-
 redef class Variable
        # Is the variable must be set before being used ?
        meth must_be_set: Bool do return false