public override IEnumerable <ProofState> EvalInit(Statement statement, ProofState state)
{
Contract.Assume(statement != null);
Contract.Assume(statement is TacticForallStmt);
_stmt = statement as TacticForallStmt;
Contract.Assert(_stmt != null);
// do basic simplification
// maybe do a check and throw an error instead?
// fixme: error returns null!
//var e = (ForallExpr) SimpTacticExpr.SimpTacExpr(state0, _stmt.Spec);
var e = (ForallExpr)SimpExpr.SimpTacticExpr(state, _stmt.Spec);
// var e = _stmt.Spec as ForallExpr;
// to rename expressions
RenameVar rn = new RenameVar();
// to rename in the body of statement
RenameVar rnBody = new RenameVar();
List <String> usedVars = state.GetAllDafnyVars().Keys.ToList();
usedVars.AddRange(state.GetAllTVars().Keys.ToList());
//List<String> tmp = new List<string>();
AllVars.DeclaredVars(_stmt.Body.Body[0], ref usedVars);
if (_stmt.Attributes != null && _stmt.Attributes.Name.Equals("vars"))
{
var attrs = _stmt.Attributes.Args;
for (int i = 0; i < attrs.Count; i++)
{
// todo: should really report an errors if first condition does not hold
var segment = attrs[i] as NameSegment;
if (segment != null && i < e.BoundVars.Count)
{
NameSegment ns = segment;
String fv;
if (GenFreeVar(ns.Name, usedVars, out fv))
{
rnBody.AddRename(ns.Name, fv);
}
rn.AddRename(e.BoundVars[i].Name, fv);
} // else we should have an error
_vars = new List <BoundVar>();
foreach (BoundVar bv in e.BoundVars)
{
_vars.Add(rn.CloneBoundVar(bv));
}
}
}
else
{
_vars = e.BoundVars;
}
foreach (var tmp in _vars)
{
state.AddDafnyVar(tmp.Name, new ProofState.VariableData {
Variable = tmp, Type = tmp.Type
});
}
// we could even break _ens into a set of all conjunctions?
// what about forall x (forall y) x
var expr = e.Term as BinaryExpr;
if (expr != null && (expr.Op.Equals(BinaryExpr.Opcode.Imp)))
{
var be = expr;
_range = rn.CloneExpr(be.E0);
var t = new MaybeFreeExpression(rn.CloneExpr(be.E1));
var l = new List <MaybeFreeExpression> {
t
};
_ens = l;
}
else
{
_range = new LiteralExpr(_stmt.Tok, true);
var t = new MaybeFreeExpression(rn.CloneExpr(e.Term));
var l = new List <MaybeFreeExpression> {
t
};
_ens = l;
}
// Note that we do not need to rename variables in the body (unless the variables in vars is changed)
InitBasicFrameCtrl(new List <Statement>(), state.IsCurFramePartial(), null, VerifyN);
state.AddNewFrame(this);
var bodyFrame = new DefaultTacticFrameCtrl();
var newBody = rnBody.CloneBlockStmt(_stmt.Body);
bodyFrame.InitBasicFrameCtrl(newBody.Body, state.IsCurFramePartial(), null, VerifyN);
bodyFrame.IsPartial = IsPartial;
state.AddNewFrame(bodyFrame);
yield return(state);
}
