public void CachedHashCodeLambdaExpr()
{
var x = new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken, "x", BasicType.Int));
var y = new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken, "x", BasicType.Int));
var body = Expr.Gt (new IdentifierExpr (Token.NoToken, x, /*immutable=*/true),
new IdentifierExpr(Token.NoToken, y, /*immutable=*/true));
var lambda = new LambdaExpr(Token.NoToken, new List<TypeVariable>(), new List<Variable>() { x, y},
null, body, /*immutable=*/true);
Assert.AreEqual(lambda.ComputeHashCode(), lambda.GetHashCode());
}
public override Expr VisitLambdaExpr(LambdaExpr node) {
Contract.Ensures(Contract.Result<Expr>() == node);
return this.VisitBinderExpr(node);
}
public void ProtectedLambdaExprBody()
{
var x = new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken, "x", BasicType.Int));
var y = new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken, "x", BasicType.Int));
var xId = new IdentifierExpr(Token.NoToken, x, /*immutable=*/true);
var yId = new IdentifierExpr(Token.NoToken, y, /*immutable=*/true);
var body = Expr.Gt(xId, yId);
var lambda = new LambdaExpr(Token.NoToken, new List<TypeVariable>(), new List<Variable>() { x, y},
null, body, /*immutable=*/true);
lambda.Body = Expr.Lt(xId, yId); // Changing the body of an immutable ExistsExpr should fail
}
public virtual Expr VisitLambdaExpr(LambdaExpr node) {
Contract.Requires(node != null);
Contract.Ensures(Contract.Result<Expr>() != null);
node = (LambdaExpr)this.VisitBinderExpr(node);
return node;
}
void LambdaExpression(out Expression e, bool allowSemi)
{
IToken x = Token.NoToken;
IToken id; BoundVar bv;
var bvs = new List<BoundVar>();
FrameExpression fe; Expression ee;
var reads = new List<FrameExpression>();
Expression req = null;
bool oneShot;
Expression body = null;
if (la.kind == 1) {
WildIdent(out id, true);
x = t; bvs.Add(new BoundVar(id, id.val, new InferredTypeProxy()));
} else if (la.kind == 50) {
Get();
x = t;
if (la.kind == 1) {
IdentTypeOptional(out bv);
bvs.Add(bv);
while (la.kind == 22) {
Get();
IdentTypeOptional(out bv);
bvs.Add(bv);
}
}
Expect(51);
} else SynErr(229);
while (la.kind == 44 || la.kind == 45) {
if (la.kind == 44) {
Get();
PossiblyWildFrameExpression(out fe, true);
reads.Add(fe);
} else {
Get();
Expression(out ee, true, false);
req = req == null ? ee : new BinaryExpr(req.tok, BinaryExpr.Opcode.And, req, ee);
}
}
LambdaArrow(out oneShot);
Expression(out body, allowSemi, true);
e = new LambdaExpr(x, oneShot, bvs, req, reads, body);
theBuiltIns.CreateArrowTypeDecl(bvs.Count);
}
void AtomExpression(out Expr/*!*/ e) {
Contract.Ensures(Contract.ValueAtReturn(out e) != null); IToken/*!*/ x; int n; BigNum bn; BigDec bd; BigFloat bf;
List<Expr>/*!*/ es; List<Variable>/*!*/ ds; Trigger trig;
List<TypeVariable>/*!*/ typeParams;
IdentifierExpr/*!*/ id;
QKeyValue kv;
e = dummyExpr;
List<Variable>/*!*/ locals;
List<Block/*!*/>/*!*/ blocks;
switch (la.kind) {
case 83: {
Get();
e = new LiteralExpr(t, false);
break;
}
case 84: {
Get();
e = new LiteralExpr(t, true);
break;
}
case 3: {
Nat(out bn);
e = new LiteralExpr(t, bn);
break;
}
case 5: case 6: {
Dec(out bd);
e = new LiteralExpr(t, bd);
break;
}
case 7: {
Float(out bf);
e = new LiteralExpr(t, bf);
break;
}
case 2: {
BvLit(out bn, out n);
e = new LiteralExpr(t, bn, n);
break;
}
case 1: {
Ident(out x);
id = new IdentifierExpr(x, x.val); e = id;
if (la.kind == 10) {
Get();
if (StartOf(9)) {
Expressions(out es);
e = new NAryExpr(x, new FunctionCall(id), es);
} else if (la.kind == 11) {
e = new NAryExpr(x, new FunctionCall(id), new List<Expr>());
} else SynErr(124);
Expect(11);
}
break;
}
case 85: {
Get();
x = t;
Expect(10);
Expression(out e);
Expect(11);
e = new OldExpr(x, e);
break;
}
case 15: {
Get();
x = t;
Expect(10);
Expression(out e);
Expect(11);
e = new NAryExpr(x, new ArithmeticCoercion(x, ArithmeticCoercion.CoercionType.ToInt), new List<Expr>{ e });
break;
}
case 16: {
Get();
x = t;
Expect(10);
Expression(out e);
Expect(11);
e = new NAryExpr(x, new ArithmeticCoercion(x, ArithmeticCoercion.CoercionType.ToReal), new List<Expr>{ e });
break;
}
case 10: {
Get();
if (StartOf(9)) {
Expression(out e);
if (e is BvBounds)
this.SemErr("parentheses around bitvector bounds " +
"are not allowed");
} else if (la.kind == 89 || la.kind == 90) {
Forall();
x = t;
QuantifierBody(x, out typeParams, out ds, out kv, out trig, out e);
if (typeParams.Count + ds.Count > 0)
e = new ForallExpr(x, typeParams, ds, kv, trig, e);
} else if (la.kind == 91 || la.kind == 92) {
Exists();
x = t;
QuantifierBody(x, out typeParams, out ds, out kv, out trig, out e);
if (typeParams.Count + ds.Count > 0)
e = new ExistsExpr(x, typeParams, ds, kv, trig, e);
} else if (la.kind == 93 || la.kind == 94) {
Lambda();
x = t;
QuantifierBody(x, out typeParams, out ds, out kv, out trig, out e);
if (trig != null)
SemErr("triggers not allowed in lambda expressions");
if (typeParams.Count + ds.Count > 0)
e = new LambdaExpr(x, typeParams, ds, kv, e);
} else SynErr(125);
Expect(11);
break;
}
case 41: {
IfThenElseExpression(out e);
break;
}
case 86: {
CodeExpression(out locals, out blocks);
e = new CodeExpr(locals, blocks);
break;
}
default: SynErr(126); break;
}
}
public override Expr VisitLambdaExpr(LambdaExpr lambda) {
var baseResult = base.VisitLambdaExpr(lambda);
lambda = baseResult as LambdaExpr;
if (lambda == null) {
return baseResult; // apparently, the base visitor already turned the lambda into something else
}
// We start by getting rid of any use of "old" inside the lambda. This is done as follows.
// For each variable "g" occurring inside lambda as "old(... g ...)", create a new name "og".
// Replace each old occurrence of "g" with "og", removing the enclosing "old" wrappers.
var oldFinder = new OldFinder();
oldFinder.Visit(lambda);
var oldSubst = new Dictionary<Variable, Expr>(); // g -> g0
var callOldMapping = new Dictionary<Variable, Expr>(); // g0 -> old(g)
foreach (var v in oldFinder.FreeOldVars) {
var g = v as GlobalVariable;
if (g != null) {
var g0 = new GlobalVariable(g.tok, new TypedIdent(g.tok, g.TypedIdent.Name + "@old", g.TypedIdent.Type));
oldSubst.Add(g, new IdentifierExpr(g0.tok, g0));
callOldMapping.Add(g0, new OldExpr(g0.tok, new IdentifierExpr(g.tok, g)));
}
}
var lambdaBody = Substituter.ApplyReplacingOldExprs(
Substituter.SubstitutionFromHashtable(new Dictionary<Variable,Expr>()),
Substituter.SubstitutionFromHashtable(oldSubst),
lambda.Body);
var lambdaAttrs = Substituter.ApplyReplacingOldExprs(
Substituter.SubstitutionFromHashtable(new Dictionary<Variable, Expr>()),
Substituter.SubstitutionFromHashtable(oldSubst),
lambda.Attributes);
if (0 < CommandLineOptions.Clo.VerifySnapshots && QKeyValue.FindStringAttribute(lambdaAttrs, "checksum") == null)
{
// Attach a dummy checksum to avoid issues in the dependency analysis.
var checksumAttr = new QKeyValue(lambda.tok, "checksum", new List<object> { "lambda expression" }, null);
if (lambdaAttrs == null)
{
lambdaAttrs = checksumAttr;
}
else
{
lambdaAttrs.AddLast(checksumAttr);
}
}
// this is ugly, the output will depend on hashing order
var subst = new Dictionary<Variable, Expr>();
var substFnAttrs = new Dictionary<Variable, Expr>();
var formals = new List<Variable>();
var callArgs = new List<Expr>();
var axCallArgs = new List<Expr>();
var dummies = new List<Variable>(lambda.Dummies);
var freeTypeVars = new List<TypeVariable>();
var fnTypeVarActuals = new List<Type/*!*/>();
var freshTypeVars = new List<TypeVariable>(); // these are only used in the lambda@n function's definition
// compute the free variables of the lambda expression, but with lambdaBody instead of lambda.Body
Set freeVars = new Set();
BinderExpr.ComputeBinderFreeVariables(lambda.TypeParameters, lambda.Dummies, lambdaBody, lambdaAttrs, freeVars);
foreach (object o in freeVars) {
// 'o' is either a Variable or a TypeVariable.
if (o is Variable) {
var v = o as Variable;
var ti = new TypedIdent(v.TypedIdent.tok, v.TypedIdent.Name, v.TypedIdent.Type);
var f = new Formal(v.tok, ti, true);
formals.Add(f);
substFnAttrs.Add(v, new IdentifierExpr(f.tok, f));
var b = new BoundVariable(v.tok, ti);
dummies.Add(b);
if (callOldMapping.ContainsKey(v)) {
callArgs.Add(callOldMapping[v]);
} else {
callArgs.Add(new IdentifierExpr(v.tok, v));
}
Expr id = new IdentifierExpr(b.tok, b);
subst.Add(v, id);
axCallArgs.Add(id);
} else {
var tv = (TypeVariable)o;
freeTypeVars.Add(tv);
fnTypeVarActuals.Add(tv);
freshTypeVars.Add(new TypeVariable(tv.tok, tv.Name));
}
}
var sw = new System.IO.StringWriter();
var wr = new TokenTextWriter(sw, true);
lambda.Emit(wr);
string lam_str = sw.ToString();
FunctionCall fcall;
IToken tok = lambda.tok;
Formal res = new Formal(tok, new TypedIdent(tok, TypedIdent.NoName, cce.NonNull(lambda.Type)), false);
if (liftedLambdas.TryGetValue(lambda, out fcall)) {
if (CommandLineOptions.Clo.TraceVerify) {
Console.WriteLine("Old lambda: {0}", lam_str);
}
} else {
if (CommandLineOptions.Clo.TraceVerify) {
Console.WriteLine("New lambda: {0}", lam_str);
}
Function fn = new Function(tok, FreshLambdaFunctionName(), freshTypeVars, formals, res, "auto-generated lambda function",
Substituter.Apply(Substituter.SubstitutionFromHashtable(substFnAttrs), lambdaAttrs));
fn.OriginalLambdaExprAsString = lam_str;
fcall = new FunctionCall(new IdentifierExpr(tok, fn.Name));
fcall.Func = fn; // resolve here
liftedLambdas[lambda] = fcall;
List<Expr/*!*/> selectArgs = new List<Expr/*!*/>();
foreach (Variable/*!*/ v in lambda.Dummies) {
Contract.Assert(v != null);
selectArgs.Add(new IdentifierExpr(v.tok, v));
}
NAryExpr axcall = new NAryExpr(tok, fcall, axCallArgs);
axcall.Type = res.TypedIdent.Type;
axcall.TypeParameters = SimpleTypeParamInstantiation.From(freeTypeVars, fnTypeVarActuals);
NAryExpr select = Expr.Select(axcall, selectArgs);
select.Type = lambdaBody.Type;
List<Type/*!*/> selectTypeParamActuals = new List<Type/*!*/>();
List<TypeVariable> forallTypeVariables = new List<TypeVariable>();
foreach (TypeVariable/*!*/ tp in lambda.TypeParameters) {
Contract.Assert(tp != null);
selectTypeParamActuals.Add(tp);
forallTypeVariables.Add(tp);
}
forallTypeVariables.AddRange(freeTypeVars);
select.TypeParameters = SimpleTypeParamInstantiation.From(lambda.TypeParameters, selectTypeParamActuals);
Expr bb = Substituter.Apply(Substituter.SubstitutionFromHashtable(subst), lambdaBody);
NAryExpr body = Expr.Eq(select, bb);
body.Type = Type.Bool;
body.TypeParameters = SimpleTypeParamInstantiation.EMPTY;
Trigger trig = new Trigger(select.tok, true, new List<Expr> { select });
lambdaFunctions.Add(fn);
lambdaAxioms.Add(new ForallExpr(tok, forallTypeVariables, dummies,
Substituter.Apply(Substituter.SubstitutionFromHashtable(subst), lambdaAttrs),
trig, body));
}
NAryExpr call = new NAryExpr(tok, fcall, callArgs);
call.Type = res.TypedIdent.Type;
call.TypeParameters = SimpleTypeParamInstantiation.From(freeTypeVars, fnTypeVarActuals);
return call;
}
public void SimpleLambda() {
var boundVar = new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken,"foo",Microsoft.Boogie.Type.Bool));
var id = new IdentifierExpr(Token.NoToken, boundVar);
// This is basically an Identity Map
var lambdaExpr = new LambdaExpr(Token.NoToken, new List<TypeVariable>() , new List<Variable>() { boundVar }, null, id);
var id2 = new IdentifierExpr(Token.NoToken, boundVar);
var lambdaExpr2 = new LambdaExpr(Token.NoToken, new List<TypeVariable>() , new List<Variable>() { boundVar }, null, id2);
Assert.AreNotSame(lambdaExpr, lambdaExpr2); // These are different references
Assert.IsTrue(lambdaExpr.Equals(lambdaExpr2)); // These are "structurally equal"
Assert.AreEqual(lambdaExpr.GetHashCode(), lambdaExpr2.GetHashCode()); // If the .Equals() is true then hash codes must be the same
}
