internal bool IsTVar(Expression expr)
{
string key = null;
if (expr is TacticLiteralExpr)
{
key = (string)((TacticLiteralExpr)expr).Value;
}
else if (expr is NameSegment)
{
key = (expr as NameSegment).Name;
}
return(key == null ? false : _state.ContainTVal(key));
}
public override IEnumerable <ProofState> Generate(Statement statement, ProofState state)
{
AssignSuchThatStmt suchThat = null;
if (statement is AssignSuchThatStmt)
{
suchThat = (AssignSuchThatStmt)statement;
}
else
{
state.ReportTacticError(statement.Tok, "Unexpected statement for suchthat(:|)");
yield break;
}
var nameExpr = suchThat.Lhss[0];
if (nameExpr is IdentifierExpr)
{
var id = nameExpr as IdentifierExpr;
name = id.Name;
}
else if (nameExpr is NameSegment)
{
var id = nameExpr as NameSegment;
if (!state.ContainTVal(id.Name))
{
state.ReportTacticError(statement.Tok, "Fail to register variable " + id.Name);
yield break;
}
else
{
name = id.Name;
}
}
else
{
state.ReportTacticError(statement.Tok, "Fail to register variable.");
yield break;
}
string errInfo;
// var expr = Expr.SimpExpr.SimpTacticExpr(state, suchThat.Expr);
var expr = suchThat.Expr;
/*
* if (!CheckExpr(expr, out errInfo)) {
* state.ReportTacticError(statement.Tok, "Unexpceted expression in suchthat statement: " + errInfo);
* yield break;
* }*/
Expression pos, neg, pred;
if (!RewriteExpr(expr as BinaryExpr, out pos, out neg, out pred))
{
state.ReportTacticError(expr.tok, "Syntax error in Suchthat expression.");
yield break;
}
if (pos != null)
{
pos = EvalExpr.EvalTacticExpression(state, pos);
if (pos == null)
{
yield break;
}
}
if (neg != null)
{
neg = EvalExpr.EvalTacticExpression(state, neg);
if (neg == null)
{
yield break;
}
}
if (pos == null)
{
state.ReportTacticError(statement.Tok, "Suchthat expression is evaluated as an empty sequence.");
yield break;
}
if (pos is SeqDisplayExpr)
{
if (neg != null && !(neg is SeqDisplayExpr))
{
state.ReportTacticError(statement.Tok, "Unexpceted expression in suchthat statement.");
yield break;
}
var eles = EvalExpr.RemoveDup((pos as SeqDisplayExpr).Elements);
if (eles.Count == 0)
{
state.ReportTacticError(statement.Tok, "The expression is evaluated as an empty set.");
yield break;
}
foreach (var item in eles)
{
var copy = state.Copy();
copy.UpdateTacticVar(name, item);
if (neg != null)
{
var inNeg = EvalExpr.EvalTacticExpression(state,
new BinaryExpr(new Token(TacnyDriver.TacticCodeTokLine, 0),
BinaryExpr.Opcode.In, item, neg));
if (inNeg is LiteralExpr && (inNeg as LiteralExpr).Value is bool)
{
if ((bool)(inNeg as LiteralExpr).Value)
{
continue;
}
}
else
{
throw new Exception("A unhandled error orrurs when evaluating a suchtaht statement");
}
}
if (pred != null)
{
var value = new BinaryExpr(new Token(TacnyDriver.TacticCodeTokLine, 0),
BinaryExpr.Opcode.Eq, suchThat.Lhss[0].Copy(), item);
var candidate = new BinaryExpr(new Token(TacnyDriver.TacticCodeTokLine, 0), BinaryExpr.Opcode.Add, value, pred);
var res = EvalExpr.EvalTacticExpression(copy, pred);
Console.WriteLine(Printer.ExprToString(res));
if (res is LiteralExpr && (res as LiteralExpr).Value is bool)
{
if (!(bool)(res as LiteralExpr).Value)
{
continue;
}
}
else
{
throw new Exception("A unhandled error orrurs when evaluating a suchtaht statement");
}
}
yield return(copy);
}
}
else
{
state.ReportTacticError(statement.Tok, "Unexpceted expression in suchthat statement.");
yield break;
}
}
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);
}
}
}