syntax: clean class VariableContext

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

diff --git a/src/syntax/typing.nit b/src/syntax/typing.nit
index 512288d..cb72b44 100644 (file)
--- a/src/syntax/typing.nit
+++ b/src/syntax/typing.nit
@@ -123,7 +123,7 @@ end
 
 # Associate symbols to variable and variables to type
 # Can be nested
-private class VariableContext
+abstract class VariableContext
        # Look for the variable from its name
        # Return null if nothing found
        meth [](s: Symbol): Variable
@@ -141,7 +141,6 @@ private class VariableContext
                _dico[v.name] = v
        end
 
-
        # The effective static type of a given variable
        # May be different from the declaration static type
        meth stype(v: Variable): MMType
@@ -153,24 +152,40 @@ private class VariableContext
        attr _dico: Map[Symbol, Variable]
 
        # Build a new VariableContext
-       meth sub: SubVariableContext
+       meth sub(node: PNode): SubVariableContext
        do
-               return new SubVariableContext.with_prev(self)
+               return new SubVariableContext.with_prev(self, node)
        end
 
        # Build a nested VariableContext with new variable information
-       meth sub_with(v: Variable, t: MMType): SubVariableContext
+       meth sub_with(node: PNode, v: Variable, t: MMType): SubVariableContext
        do
-               return new CastVariableContext.with_prev(self, v, t)
+               return new CastVariableContext.with_prev(self, node, v, t)
        end
 
-       init
-       do 
+       # The visitor of the context (used to display error)
+       attr _visitor: AbsSyntaxVisitor
+
+       # The syntax node that introduced the context
+       readable attr _node: PNode
+
+       init(visitor: AbsSyntaxVisitor, node: PNode)
+       do
+               _visitor = visitor
+               _node = node
                _dico = new HashMap[Symbol, Variable]
        end
 end
 
-private class SubVariableContext
+class RootVariableContext
+special VariableContext
+       init(visitor: AbsSyntaxVisitor, node: PNode)
+       do
+               super(visitor, node)
+       end
+end
+
+class SubVariableContext
 special VariableContext
        readable attr _prev: VariableContext
 
@@ -188,14 +203,14 @@ special VariableContext
                return prev.stype(v)
        end
 
-       init with_prev(p: VariableContext)
+       init with_prev(p: VariableContext, node: PNode)
        do
-               init
+               init(p._visitor, node)
                _prev = p
        end
 end
 
-private class CastVariableContext
+class CastVariableContext
 special SubVariableContext
        attr _variable: Variable
        attr _var_type: MMType
@@ -208,9 +223,9 @@ special SubVariableContext
                return prev.stype(v)
        end
 
-       init with_prev(p: VariableContext, v: Variable, t: MMType)
+       init with_prev(p: VariableContext, node: PNode, v: Variable, t: MMType)
        do
-               super(p)
+               super(p, node)
                _variable = v
                _var_type =t
        end
@@ -250,7 +265,7 @@ redef class AMethPropdef
        redef readable attr _self_var: ParamVariable
        redef meth accept_typing(v)
        do
-               v.variable_ctx = new VariableContext
+               v.variable_ctx = new RootVariableContext(v, self)
                _self_var = v.self_var
                super
        end
@@ -324,7 +339,7 @@ redef class AClosureDecl
                v.variable_ctx.add(variable)
 
                var old_var_ctx = v.variable_ctx
-               v.variable_ctx = v.variable_ctx.sub
+               v.variable_ctx = v.variable_ctx.sub(self)
 
                _escapable = new EscapableClosure(self, variable.closure, null)
                v.escapable_ctx.push(_escapable)
@@ -398,7 +413,7 @@ redef class ABlockExpr
        redef meth accept_typing(v)
        do
                var old_var_ctx = v.variable_ctx
-               v.variable_ctx = v.variable_ctx.sub
+               v.variable_ctx = v.variable_ctx.sub(self)
 
                super
 
@@ -493,10 +508,13 @@ redef class AWhileExpr
        do
                _escapable = new EscapableBlock(self)
                v.escapable_ctx.push(_escapable)
+               var old_var_ctx = v.variable_ctx
+               v.variable_ctx = v.variable_ctx.sub(self)
 
                super
 
                v.check_conform_expr(n_expr, v.type_bool)
+               v.variable_ctx = old_var_ctx
                v.escapable_ctx.pop
                _is_typed = true
        end
@@ -515,7 +533,8 @@ redef class AForExpr
                _escapable = new EscapableBlock(self)
                v.escapable_ctx.push(_escapable)
 
-               v.variable_ctx = v.variable_ctx.sub
+               var old_var_ctx = v.variable_ctx
+               v.variable_ctx = v.variable_ctx.sub(self)
                var va = new AutoVariable(n_id.to_symbol, self)
                variable = va
                v.variable_ctx.add(va)
@@ -552,10 +571,7 @@ redef class AForExpr
                if n_block != null then v.visit(n_block)
 
                # pop context
-               var varctx = v.variable_ctx
-               assert varctx isa SubVariableContext
-               v.variable_ctx = varctx.prev
-
+               v.variable_ctx = old_var_ctx
                v.escapable_ctx.pop
                _is_typed = true
        end
@@ -1450,7 +1466,8 @@ redef class AClosureDef
 
                closure = esc.closure
 
-               v.variable_ctx = v.variable_ctx.sub
+               var old_var_ctx = v.variable_ctx
+               v.variable_ctx = v.variable_ctx.sub(self)
                variables = new Array[AutoVariable]
                for i in [0..n_id.length[ do
                        var va = new AutoVariable(n_id[i].to_symbol, self)
@@ -1461,6 +1478,7 @@ redef class AClosureDef
 
                _accept_typing2 = true
                accept_typing(v)
+               v.variable_ctx = old_var_ctx
        end
 end
 
@@ -1486,7 +1504,7 @@ special ATypeCheckExpr
                check_expr_cast(v, n_expr, n_type)
                var variable = n_expr.its_variable
                if variable != null then
-                       _if_true_variable_ctx = v.variable_ctx.sub_with(variable, n_type.stype)
+                       _if_true_variable_ctx = v.variable_ctx.sub_with(self, variable, n_type.stype)
                end
                _stype = v.type_bool
                _is_typed = true