Add default values for some primitive type attributes.

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

diff --git a/src/syntax/control_flow.nit b/src/syntax/control_flow.nit
index 50fcb57..f044cd1 100644 (file)
--- a/src/syntax/control_flow.nit
+++ b/src/syntax/control_flow.nit
@@ -29,6 +29,17 @@ redef class MMSrcModule
        end
 end
 
+redef class Variable
+       # Is the variable must be set before being used ?
+       meth must_be_set: Bool do return false
+end
+
+redef class VarVariable
+       redef meth must_be_set do return true
+end
+
+
+
 # Control flow visitor
 # * Check reachability in methods
 # * Associate breaks and continues
@@ -41,14 +52,14 @@ special AbsSyntaxVisitor
        end
 
        # Number of nested once
-       readable writable attr _once_count: Int
+       readable writable attr _once_count: Int = 0
 
        # Current knowledge about variables types
        readable writable attr _control_flow_ctx: ControlFlowContext
 
        meth check_is_set(n: PNode, v: Variable)
        do
-               if not control_flow_ctx.is_set(v) then
+               if v.must_be_set and not control_flow_ctx.is_set(v) then
                        error(n, "Error: variable '{v}' is possibly unset.")
                        var cfc = control_flow_ctx
                        while cfc != null do
@@ -70,15 +81,12 @@ private class ControlFlowContext
        # Previous control flow context if any
        readable attr _prev: ControlFlowContext
 
-       # Is a return met?
-       readable writable attr _has_return: Bool 
-
        # Is a control flow break met? (return, break, continue)
-       readable writable attr _unreash: Bool
+       readable writable attr _unreash: Bool = false
 
        # Is a control flow already broken?
        # Used to avoid repeating the same error message
-       readable writable attr _already_unreash: Bool
+       readable writable attr _already_unreash: Bool = false
 
        # Current controlable block (for or while)
        readable writable attr _base_block: AControlableBlock
@@ -94,17 +102,16 @@ private class ControlFlowContext
 
        meth sub: ControlFlowContext
        do
-               return new ControlFlowContext.with(self)
+               return new ControlFlowContext.with_prev(self)
        end
 
        init
        do 
        end
 
-       init with(p: ControlFlowContext)
+       init with_prev(p: ControlFlowContext)
        do
                _prev = p
-               _has_return = p.has_return
                _unreash = p.unreash
                _already_unreash = p.already_unreash
                _base_block = p.base_block
@@ -132,20 +139,12 @@ redef class AConcreteMethPropdef
        redef meth accept_control_flow(v)
        do
                super
-               if v.control_flow_ctx.has_return == false and method.signature.return_type != null then
-                       v.error(self, "Control error: Reached end of function.")
+               if v.control_flow_ctx.unreash == false and method.signature.return_type != null then
+                       v.error(self, "Control error: Reached end of function (a 'return' with a value was expected).")
                end
        end
 end
 
-redef class PParam
-       redef meth accept_control_flow(v)
-       do
-               super
-               v.mark_is_set(variable)
-       end
-end
-
 redef class AVardeclExpr
        redef meth accept_control_flow(v)
        do
@@ -171,7 +170,6 @@ redef class AReturnExpr
        redef meth accept_control_flow(v)
        do
                super
-               v.control_flow_ctx.has_return = true
                v.control_flow_ctx.unreash = true
        end
 end
@@ -214,7 +212,6 @@ redef class AAbortExpr
        redef meth accept_control_flow(v)
        do
                super
-               v.control_flow_ctx.has_return = true
                v.control_flow_ctx.unreash = true
        end
 end
@@ -241,7 +238,6 @@ redef class AIfExpr
                        v.visit(n_else)
 
                        # Merge then and else in the old control_flow
-                       old_control_flow_ctx.has_return = v.control_flow_ctx.has_return and then_control_flow_ctx.has_return
                        old_control_flow_ctx.unreash = v.control_flow_ctx.unreash and then_control_flow_ctx.unreash
 
                        if v.control_flow_ctx.unreash then v.control_flow_ctx = then_control_flow_ctx
@@ -282,15 +278,6 @@ redef class AForExpr
 special AControlableBlock
 end
 
-redef class AForVardeclExpr
-       redef meth accept_control_flow(v)
-       do
-               super
-               v.mark_is_set(variable)
-       end
-end     
-
-
 redef class AVarExpr
        redef meth accept_control_flow(v)
        do