syntax: if_false_variable_ctx

[nit.git] / src / syntax / typing.nit

diff --git a/src/syntax/typing.nit b/src/syntax/typing.nit
index 679b88e..f9d5eba 100644 (file)
--- a/src/syntax/typing.nit
+++ b/src/syntax/typing.nit
@@ -65,9 +65,14 @@ special AbsSyntaxVisitor
        private meth use_if_true_variable_ctx(e: PExpr)
        do
                var ctx = e.if_true_variable_ctx
-               if ctx != null then
-                       variable_ctx = ctx
-               end
+               if ctx != null then variable_ctx = ctx
+       end
+
+       # Make the if_false_variable_ctx of the expression effective
+       private meth use_if_false_variable_ctx(e: PExpr)
+       do
+               var ctx = e.if_false_variable_ctx
+               if ctx != null then variable_ctx = ctx
        end
 
        # Number of nested once
@@ -303,6 +308,9 @@ redef class PExpr
 
        # The variable type information if current boolean expression is true
        readable private attr _if_true_variable_ctx: VariableContext
+
+       # The variable type information if current boolean expression is false
+       readable private attr _if_false_variable_ctx: VariableContext
 end
 
 redef class AVardeclExpr
@@ -420,24 +428,31 @@ redef class AIfExpr
                v.visit(n_expr)
                v.check_conform_expr(n_expr, v.type_bool)
 
+               # Prepare 'then' context
                v.use_if_true_variable_ctx(n_expr)
-               v.variable_ctx = v.variable_ctx.sub(n_then)
 
-               v.visit(n_then)
+               # Process the 'then'
+               if n_then != null then
+                       v.variable_ctx = v.variable_ctx.sub(n_then)
+                       v.visit(n_then)
+               end
 
-               if n_else == null then
-                       # Restore variable ctx since the 'then' block is optional
-                       v.variable_ctx = old_var_ctx
-               else
-                       # Remember what appened in the 'then'
-                       var then_var_ctx = v.variable_ctx
-                       # Reset to process the 'else'
-                       v.variable_ctx = old_var_ctx.sub(n_else)
+               # Remember what appened in the 'then'
+               var then_var_ctx = v.variable_ctx
+
+               # Prepare 'else' context
+               v.variable_ctx = old_var_ctx
+               v.use_if_false_variable_ctx(n_expr)
+
+               # Process the 'else'
+               if n_else != null then
+                       v.variable_ctx = v.variable_ctx.sub(n_else)
                        v.visit(n_else)
-                       # Merge then and else in the old control_flow
-                       old_var_ctx.merge2(then_var_ctx, v.variable_ctx)
-                       v.variable_ctx = old_var_ctx
                end
+
+               # Merge 'then' and 'else' contexts
+               old_var_ctx.merge2(then_var_ctx, v.variable_ctx)
+               v.variable_ctx = old_var_ctx
                _is_typed = true
        end
 end
@@ -635,6 +650,7 @@ redef class AIfexprExpr
                v.use_if_true_variable_ctx(n_expr)
                v.visit(n_then)
                v.variable_ctx = old_var_ctx
+               v.use_if_false_variable_ctx(n_expr)
                v.visit(n_else)
 
                v.check_conform_expr(n_expr, v.type_bool)
@@ -655,6 +671,20 @@ end
 redef class AOrExpr
        redef meth after_typing(v)
        do
+               var old_var_ctx = v.variable_ctx
+
+               v.visit(n_expr)
+               v.use_if_false_variable_ctx(n_expr)
+
+               v.visit(n_expr2)
+               if n_expr2.if_false_variable_ctx != null then 
+                       _if_false_variable_ctx = n_expr2.if_false_variable_ctx
+               else
+                       _if_false_variable_ctx = v.variable_ctx
+               end
+
+               v.variable_ctx = old_var_ctx
+
                v.check_conform_expr(n_expr, v.type_bool)
                v.check_conform_expr(n_expr2, v.type_bool)
                _stype = v.type_bool
@@ -690,6 +720,11 @@ redef class ANotExpr
        redef meth after_typing(v)
        do
                v.check_conform_expr(n_expr, v.type_bool)
+
+               # Invert if_true/if_false information
+               _if_false_variable_ctx = n_expr._if_true_variable_ctx
+               _if_true_variable_ctx = n_expr._if_false_variable_ctx
+
                _stype = v.type_bool
                _is_typed = true
        end