public override BinderExpr VisitBinderExpr(BinderExpr node)
{
var oldToNew = node.Dummies.ToDictionary(x => x, x => new BoundVariable(Token.NoToken, new TypedIdent(Token.NoToken, prefix + x.Name, x.TypedIdent.Type), x.Attributes));
foreach (var x in node.Dummies)
{
bound.Add(x, Expr.Ident(oldToNew[x]));
}
BinderExpr expr = base.VisitBinderExpr(node);
expr.Dummies = node.Dummies.Select(x => oldToNew[x]).ToList <Variable>();
// We process triggers of quantifer expressions here, because otherwise the
// substitutions for bound variables have to be leaked outside this procedure.
if (node is QuantifierExpr quantifierExpr)
{
if (quantifierExpr.Triggers != null)
{
((QuantifierExpr)expr).Triggers = this.VisitTrigger(quantifierExpr.Triggers);
}
}
foreach (var x in node.Dummies)
{
bound.Remove(x);
}
return(expr);
}
bool IEqualityComparer <Expr> .Equals(Expr x, Expr y)
{
var nx = deBruijn.Rename(x);
var ny = deBruijn.Rename(y);
return(BinderExpr.EqualWithAttributesAndTriggers(nx, ny));
}
public override BinderExpr VisitBinderExpr(BinderExpr node) {
base.VisitBinderExpr(node);
// visit attributes, even though StandardVisitor does not do that (but maybe it should?)
if (node.Attributes != null) {
this.Visit(node.Attributes);
}
return node;
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
if (node.TypeParameters.Count > 0)
{
isMonomorphizable = false;
}
return(base.VisitBinderExpr(node));
}
public virtual BinderExpr VisitBinderExpr(BinderExpr node)
{
Contract.Requires(node != null);
Contract.Ensures(Contract.Result <BinderExpr>() != null);
node.Body = this.VisitExpr(node.Body);
node.Dummies = this.VisitVariableSeq(node.Dummies);
//node.Type = this.VisitType(node.Type);
return(node);
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
var subst = new Dictionary <Variable, Expr>();
var newBound = new List <Variable>();
foreach (var bv in node.Dummies)
{
var bvNew = boundVars[boundVarCount++, bv.TypedIdent.Type];
newBound.Add(bvNew);
subst[bv] = new IdentifierExpr(Token.NoToken, bvNew);
}
node.Dummies = this.VisitVariableSeq(newBound);
node.Body = this.VisitExpr(Substituter.Apply(Substituter.SubstitutionFromHashtable(subst), node.Body));
return(node);
}
public override bool Equals(object obj)
{
if (obj == null)
{
return(false);
}
if (!(obj is BinderExpr) ||
this.Kind != ((BinderExpr)obj).Kind)
{
return(false);
}
BinderExpr other = (BinderExpr)obj;
// Note, we consider quantifiers equal modulo the Triggers.
return(object.Equals(this.TypeParameters, other.TypeParameters) &&
object.Equals(this.Dummies, other.Dummies) &&
object.Equals(this.Body, other.Body));
}
public override BinderExpr VisitBinderExpr(BinderExpr node) {
//Contract.Requires(node != null);
Contract.Ensures(Contract.Result<BinderExpr>() != null);
return base.VisitBinderExpr((BinderExpr)node.Clone());
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
// don't go into binder expression, since the terms in there may have more bound variables
return(node);
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
if (node.TypeParameters.Count > 0)
isMonomorphic = false;
return base.VisitBinderExpr(node);
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
Contract.Ensures(Contract.Result<BinderExpr>() == node);
this.VisitExpr(node.Body);
this.VisitVariableSeq(node.Dummies);
// this.VisitType(node.Type);
return node;
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
Debug.Assert(false);
return base.VisitBinderExpr(node);
}
public override BinderExpr VisitBinderExpr(BinderExpr node) {
// don't go into binder expression, since the terms in there may have more bound variables
return node;
}
public override BinderExpr VisitBinderExpr(BinderExpr node)
{
//Contract.Requires(node != null);
Contract.Ensures(Contract.Result <BinderExpr>() != null);
return(base.VisitBinderExpr((BinderExpr)node.Clone()));
}
/// <summary>
/// Performs lambda lifting (see <see cref="LambdaHelper.ExpandLambdas"/>) by replacing the lambda's
/// free variables with bound ones.
/// </summary>
/// <param name="lambda">A lambda expression
/// <code>(lambda x1: T1 ... x_n: T_n :: t)</code>
/// where <c>t</c> contains the free variables <c>y1</c>, ..., <c>y_m</c>.
/// </param>
/// <returns>
/// <list type="bullet">
/// <item>
/// A function application <c>f(y1, ..., y_m)</c> where <c>f</c>'s body is defined to be the result of
/// replacing the free variables <c>y1</c>, ..., <c>y_m</c> in <c>t</c> with bound variables
/// <c>b1</c>, ..., <c>b_m</c>.
/// </item>
/// <item>
/// Adds a definition and axiom for <c>f</c> to <see cref="lambdaFunctions"/> and <see cref="lambdaAxioms"/>.
/// Memoizes <c>f</c> as the lifted lambda for <para>lambda</para>.
/// </item>
/// </list>
/// </returns>
private Expr LiftLambdaFreeVars(LambdaExpr lambda)
{
// 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.SubstitutionFromDictionary(new Dictionary<Variable, Expr>()),
Substituter.SubstitutionFromDictionary(oldSubst),
lambda.Body);
var lambdaAttrs = Substituter.ApplyReplacingOldExprs(
Substituter.SubstitutionFromDictionary(new Dictionary<Variable, Expr>()),
Substituter.SubstitutionFromDictionary(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, null, 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.SubstitutionFromDictionary(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.SubstitutionFromDictionary(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.SubstitutionFromDictionary(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 virtual BinderExpr VisitBinderExpr(BinderExpr node) {
Contract.Requires(node != null);
Contract.Ensures(Contract.Result<BinderExpr>() != null);
node.Body = this.VisitExpr(node.Body);
node.Dummies = this.VisitVariableSeq(node.Dummies);
//node.Type = this.VisitType(node.Type);
return node;
}
public override BinderExpr VisitBinderExpr(BinderExpr node) {
base.VisitBinderExpr(node);
// visit attributes, even though StandardVisitor does not do that (but maybe it should?)
if (node.Attributes != null) {
this.Visit(node.Attributes);
}
return node;
}