public override Expression Generate(Expression expr, ProofState proofState)
{
if (expr is ExprDotName)
{
var src = Expr.SimpExpr.SimpTacticExpr(proofState, (expr as ExprDotName).Lhs);
if (src is NameSegment && proofState.ContainDafnyVar(src as NameSegment))
{
var type = proofState.GetDafnyVarType((src as NameSegment).Name);
if (type is UserDefinedType)
{
return(new LiteralExpr(new Boogie.Token(TacnyDriver.TacticCodeTokLine, 0), true));
}
}
return(new LiteralExpr(new Boogie.Token(TacnyDriver.TacticCodeTokLine, 0), false));
}
else
{
proofState.ReportTacticError(expr.tok, "Illform for \"const?\", expect form in the shape of *.const?");
return(null);
}
}
public override IEnumerable <ProofState> EvalInit(Statement statement, ProofState state)
{
Contract.Assume(statement != null);
Contract.Assume(statement is TacticCasesBlockStmt);
var stmt = statement as TacticCasesBlockStmt;
NameSegment caseVar;
//get guards
Debug.Assert(stmt != null, "stmt != null");
var guard = stmt.Guard as ParensExpression;
if (guard == null)
{
caseVar = stmt.Guard as NameSegment;
}
else
{
caseVar = guard.E as NameSegment;
}
var srcVar = SimpExpr.SimpTacticExpr(state, caseVar) as NameSegment;
if (srcVar == null)
{
state.ReportTacticError(statement.Tok, Printer.ExprToString(caseVar) + " is not a valid variable.");
yield break;
}
var datatype = state.GetDafnyVarType(srcVar.Name).AsDatatype;
if (datatype == null)
{
state.ReportTacticError(statement.Tok, Printer.ExprToString(caseVar) + " is not an inductive datatype variable.");
yield break;
}
if (statement.Attributes != null && statement.Attributes.Name.Equals("vars"))
{
_nameVars = new List <string>();
var attrs = statement.Attributes.Args;
foreach (var attr in attrs)
{
var segment = attr as NameSegment;
if (segment != null && !state.ContainDafnyVar(segment))
{
_nameVars.Add(segment.Name);
}
}
}
//generate a test program to check which cases need to apply tacny
bool[] ctorFlags;
InitCtorFlags(datatype, out ctorFlags);
List <Func <int, List <Statement> > > fList = new List <Func <int, List <Statement> > >();
int i;
for (i = 0; i < datatype.Ctors.Count; i++)
{
fList.Add(GenerateAssumeFalseStmtAsStmtList);
}
//var matchStmt = GenerateMatchStmt(state.TacticApplication.Tok.line, srcVar.Copy(), datatype, fList);
var matchStmt = GenerateMatchStmt(TacnyDriver.TacticCodeTokLine, srcVar.Copy(), datatype, fList);
_matchStmt = matchStmt;
var matchCtrl = this;
//use a dummystmt to creat a frame for match, note that this stmts is never be evaluated
var dummystmt = new List <Statement>();
dummystmt.Add(stmt);
dummystmt.Add(stmt);
_matchStmt = matchStmt;
matchCtrl.InitBasicFrameCtrl(dummystmt, state.IsCurFramePartial(), null, VerifyN);
state.AddNewFrame(matchCtrl);
//push a frame for the first case
var caseCtrl = new DefaultTacticFrameCtrl();
caseCtrl.InitBasicFrameCtrl(stmt.Body.Body, state.IsCurFramePartial(), null, VerifyN);
state.AddNewFrame(caseCtrl);
foreach (var tmp in matchStmt.Cases[0].CasePatterns)
{
state.AddDafnyVar(tmp.Var.Name, new ProofState.VariableData {
Variable = tmp.Var, Type = tmp.Var.Type
});
}
//with this flag set to true, dafny will check the case brnach before evaluates any tacny code
state.NeedVerify = true;
yield return(state);
}
