internal Expression EvalTVar(Expression expr, bool deref)
{
string key = null;
if (expr is TacticLiteralExpr)
{
key = (string)((TacticLiteralExpr)expr).Value;
}
else if (expr is NameSegment)
{
key = (expr as NameSegment).Name;
}
if (key == null)
{
throw new Exception("expression for TVar can only be TacticLiteralExpr or NameSegment: " + expr);
}
var value = _state.GetTVarValue(key);
if (deref && value is TacticLiteralExpr && IsTVar(value as TacticLiteralExpr))
{
return(EvalTVar(value as TacticLiteralExpr, true));
}
else
{
return(value);
}
}
public override IEnumerable <ProofState> EvalInit(Statement statement, ProofState state)
{
var tacApsStmt = statement as UpdateStmt;
if (tacApsStmt != null)
{
var aps = ((ExprRhs)tacApsStmt.Rhss[0]).Expr as ApplySuffix;
var tactic = state.GetTactic(aps) as Tactic;
var frameCtrl = new DefaultTacticFrameCtrl();
if (tactic != null)
{
//unfolding preconditions
List <Statement> body = new List <Statement>();
if (tactic.Req != null)
{
foreach (var expr in tactic.Req)
{
body.Add(
new TacticAssertStmt(
new Token(TacnyDriver.TacticCodeTokLine, 0)
{
val = "tassert"
},
new Token(TacnyDriver.TacticCodeTokLine, 0)
{
val = ";"
},
expr.E,
null, false));
}
}
body.AddRange(tactic.Body.Body);
//unfolding postcondition
if (tactic.Ens != null)
{
foreach (var expr in tactic.Ens)
{
body.Add(
new TacticAssertStmt(
new Token(TacnyDriver.TacticCodeTokLine, 0)
{
val = "tassert"
},
new Token(TacnyDriver.TacticCodeTokLine, 0)
{
val = ";"
},
expr.E,
null, false));
}
}
if (aps != null && aps.Args.Count != tactic.Ins.Count)
{
state.ReportTacticError(tacApsStmt.Tok,
$"Wrong number of method arguments (got {aps.Args.Count}, expected {tactic.Ins.Count})");
yield break;
}
for (var index = 0; index < aps.Args.Count; index++)
{
var arg = aps.Args[index];
var segment = arg as NameSegment;
if (segment != null)
{
var name = segment.Name;
if (state.ContainTVal(name))
{
// in the case that referring to an exisiting tvar, dereference it
arg = state.GetTVarValue(name) as Expression;
}
else
{
state.ReportTacticError(tacApsStmt.Tok,
$"Fail to dereferenen argument({name})");
yield break;
}
}
state.AddTacnyVar(tactic.Ins[index].Name, arg);
}
frameCtrl.InitBasicFrameCtrl(body, true, tacApsStmt.Rhss[0].Attributes, VerifyN, null, tactic.Attributes);
if (!frameCtrl.enabled)
{
yield return(state);
yield break;
}
state.AddNewFrame(frameCtrl);
yield return(state);
}
}
}