void FunctionDecl(MemberModifiers mmod, bool isWithinAbstractModule, out Function/*!*/ f)
{
Contract.Ensures(Contract.ValueAtReturn(out f)!=null);
Attributes attrs = null;
IToken/*!*/ id = Token.NoToken; // to please compiler
List<TypeParameter/*!*/> typeArgs = new List<TypeParameter/*!*/>();
List<Formal/*!*/> formals = new List<Formal/*!*/>();
Type/*!*/ returnType = new BoolType();
List<Expression/*!*/> reqs = new List<Expression/*!*/>();
List<Expression/*!*/> ens = new List<Expression/*!*/>();
List<FrameExpression/*!*/> reads = new List<FrameExpression/*!*/>();
List<Expression/*!*/> decreases;
Expression body = null;
bool isPredicate = false; bool isIndPredicate = false; bool isCoPredicate = false;
bool isFunctionMethod = false;
IToken bodyStart = Token.NoToken;
IToken bodyEnd = Token.NoToken;
IToken signatureEllipsis = null;
bool missingOpenParen;
if (la.kind == 38) {
Get();
if (la.kind == 84) {
Get();
isFunctionMethod = true;
}
if (mmod.IsGhost) { SemErr(t, "functions cannot be declared 'ghost' (they are ghost by default)"); }
while (la.kind == 46) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 50 || la.kind == 52) {
if (la.kind == 52) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, formals);
Expect(21);
Type(out returnType);
} else if (la.kind == 59) {
Get();
signatureEllipsis = t;
} else SynErr(153);
} else if (la.kind == 39) {
Get();
isPredicate = true;
if (la.kind == 84) {
Get();
isFunctionMethod = true;
}
if (mmod.IsGhost) { SemErr(t, "predicates cannot be declared 'ghost' (they are ghost by default)"); }
while (la.kind == 46) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (StartOf(8)) {
if (la.kind == 52) {
GenericParameters(typeArgs);
}
missingOpenParen = true;
if (la.kind == 50) {
Formals(true, isFunctionMethod, formals);
missingOpenParen = false;
}
if (missingOpenParen) { errors.Warning(t, "with the new support of higher-order functions in Dafny, parentheses-less predicates are no longer supported; in the new syntax, parentheses are required for the declaration and uses of predicates, even if the predicate takes no additional arguments"); }
if (la.kind == 21) {
Get();
SemErr(t, "predicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 59) {
Get();
signatureEllipsis = t;
} else SynErr(154);
} else if (la.kind == 40) {
Get();
Expect(39);
isIndPredicate = true;
if (mmod.IsGhost) { SemErr(t, "inductive predicates cannot be declared 'ghost' (they are ghost by default)"); }
while (la.kind == 46) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 50 || la.kind == 52) {
if (la.kind == 52) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, formals);
if (la.kind == 21) {
Get();
SemErr(t, "inductive predicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 59) {
Get();
signatureEllipsis = t;
} else SynErr(155);
} else if (la.kind == 42) {
Get();
isCoPredicate = true;
if (mmod.IsGhost) { SemErr(t, "copredicates cannot be declared 'ghost' (they are ghost by default)"); }
while (la.kind == 46) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 50 || la.kind == 52) {
if (la.kind == 52) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, formals);
if (la.kind == 21) {
Get();
SemErr(t, "copredicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 59) {
Get();
signatureEllipsis = t;
} else SynErr(156);
} else SynErr(157);
decreases = isIndPredicate || isCoPredicate ? null : new List<Expression/*!*/>();
while (StartOf(9)) {
FunctionSpec(reqs, reads, ens, decreases);
}
if (la.kind == 46) {
FunctionBody(out body, out bodyStart, out bodyEnd);
}
if (!isWithinAbstractModule && DafnyOptions.O.DisallowSoundnessCheating && body == null && ens.Count > 0 && !Attributes.Contains(attrs, "axiom") && !Attributes.Contains(attrs, "imported")) {
SemErr(t, "a function with an ensures clause must have a body, unless given the :axiom attribute");
}
IToken tok = theVerifyThisFile ? id : new IncludeToken(id);
if (isPredicate) {
f = new Predicate(tok, id.val, mmod.IsStatic, mmod.IsProtected, !isFunctionMethod, typeArgs, formals,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, Predicate.BodyOriginKind.OriginalOrInherited, attrs, signatureEllipsis);
} else if (isIndPredicate) {
f = new InductivePredicate(tok, id.val, mmod.IsStatic, mmod.IsProtected, typeArgs, formals,
reqs, reads, ens, body, attrs, signatureEllipsis);
} else if (isCoPredicate) {
f = new CoPredicate(tok, id.val, mmod.IsStatic, mmod.IsProtected, typeArgs, formals,
reqs, reads, ens, body, attrs, signatureEllipsis);
} else {
f = new Function(tok, id.val, mmod.IsStatic, mmod.IsProtected, !isFunctionMethod, typeArgs, formals, returnType,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, attrs, signatureEllipsis);
}
f.BodyStartTok = bodyStart;
f.BodyEndTok = bodyEnd;
theBuiltIns.CreateArrowTypeDecl(formals.Count);
if (isIndPredicate || isCoPredicate) {
// also create an arrow type for the corresponding prefix predicate
theBuiltIns.CreateArrowTypeDecl(formals.Count + 1);
}
}
void FunctionDecl(DeclModifierData dmod, bool isWithinAbstractModule, out Function/*!*/ f)
{
Contract.Ensures(Contract.ValueAtReturn(out f)!=null);
Attributes attrs = null;
IToken/*!*/ id = Token.NoToken; // to please compiler
List<TypeParameter/*!*/> typeArgs = new List<TypeParameter/*!*/>();
List<Formal/*!*/> formals = new List<Formal/*!*/>();
Type/*!*/ returnType = new BoolType();
List<Expression/*!*/> reqs = new List<Expression/*!*/>();
List<Expression/*!*/> ens = new List<Expression/*!*/>();
List<FrameExpression/*!*/> reads = new List<FrameExpression/*!*/>();
List<Expression/*!*/> decreases;
Expression body = null;
bool isPredicate = false; bool isIndPredicate = false; bool isCoPredicate = false;
bool isFunctionMethod = false;
IToken bodyStart = Token.NoToken;
IToken bodyEnd = Token.NoToken;
IToken signatureEllipsis = null;
bool missingOpenParen;
bool isTwoState = false;
if (la.kind == 44) {
Get();
isTwoState = true;
}
if (la.kind == 41) {
Get();
if (la.kind == 90) {
Get();
if (isTwoState) { SemErr(t, "twostate functions are supported only as a ghosts, not as function methods"); }
else { isFunctionMethod = true; }
}
AllowedDeclModifiers allowed = AllowedDeclModifiers.AlreadyGhost | AllowedDeclModifiers.Static;
if (!isTwoState) { allowed |= AllowedDeclModifiers.Protected; }
string caption = "Functions";
if (isFunctionMethod) {
allowed |= AllowedDeclModifiers.Extern;
caption = "Function methods";
}
CheckDeclModifiers(dmod, caption, allowed);
while (la.kind == 50) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 54 || la.kind == 56) {
if (la.kind == 56) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, isTwoState, formals);
Expect(22);
Type(out returnType);
} else if (la.kind == 63) {
Get();
signatureEllipsis = t;
} else SynErr(171);
} else if (la.kind == 42) {
Get();
isPredicate = true;
if (la.kind == 90) {
Get();
if (isTwoState) { SemErr(t, "twostate predicates are supported only as a ghosts, not as predicate methods"); }
else { isFunctionMethod = true; }
}
AllowedDeclModifiers allowed = AllowedDeclModifiers.AlreadyGhost | AllowedDeclModifiers.Static;
if (!isTwoState) { allowed |= AllowedDeclModifiers.Protected; }
string caption = "Predicates";
if (isFunctionMethod) {
allowed |= AllowedDeclModifiers.Extern;
caption = "Predicate methods";
}
CheckDeclModifiers(dmod, caption, allowed);
while (la.kind == 50) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (StartOf(11)) {
if (la.kind == 56) {
GenericParameters(typeArgs);
}
missingOpenParen = true;
if (la.kind == 54) {
Formals(true, isFunctionMethod, isTwoState, formals);
missingOpenParen = false;
}
if (missingOpenParen) { errors.Warning(t, "with the new support of higher-order functions in Dafny, parentheses-less predicates are no longer supported; in the new syntax, parentheses are required for the declaration and uses of predicates, even if the predicate takes no additional arguments"); }
if (la.kind == 22) {
Get();
SemErr(t, "predicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 63) {
Get();
signatureEllipsis = t;
} else SynErr(172);
} else if (la.kind == 43) {
Contract.Assert(!isTwoState); // the IsFunctionDecl check checks that "twostate" is not followed by "inductive"
Get();
Expect(42);
isIndPredicate = true;
CheckDeclModifiers(dmod, "Inductive predicates",
AllowedDeclModifiers.AlreadyGhost | AllowedDeclModifiers.Static | AllowedDeclModifiers.Protected);
while (la.kind == 50) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 54 || la.kind == 56) {
if (la.kind == 56) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, false, formals);
if (la.kind == 22) {
Get();
SemErr(t, "inductive predicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 63) {
Get();
signatureEllipsis = t;
} else SynErr(173);
} else if (la.kind == 46) {
Contract.Assert(!isTwoState); // the IsFunctionDecl check checks that "twostate" is not followed by "copredicate"
Get();
isCoPredicate = true;
CheckDeclModifiers(dmod, "Copredicates",
AllowedDeclModifiers.AlreadyGhost | AllowedDeclModifiers.Static | AllowedDeclModifiers.Protected);
while (la.kind == 50) {
Attribute(ref attrs);
}
NoUSIdent(out id);
if (la.kind == 54 || la.kind == 56) {
if (la.kind == 56) {
GenericParameters(typeArgs);
}
Formals(true, isFunctionMethod, false, formals);
if (la.kind == 22) {
Get();
SemErr(t, "copredicates do not have an explicitly declared return type; it is always bool");
}
} else if (la.kind == 63) {
Get();
signatureEllipsis = t;
} else SynErr(174);
} else SynErr(175);
decreases = isIndPredicate || isCoPredicate ? null : new List<Expression/*!*/>();
while (StartOf(12)) {
FunctionSpec(reqs, reads, ens, decreases);
}
if (la.kind == 50) {
FunctionBody(out body, out bodyStart, out bodyEnd);
}
if (!isWithinAbstractModule && DafnyOptions.O.DisallowSoundnessCheating && body == null && ens.Count > 0 &&
!Attributes.Contains(attrs, "axiom") && !Attributes.Contains(attrs, "imported")) {
SemErr(t, "a function with an ensures clause must have a body, unless given the :axiom attribute");
}
EncodeExternAsAttribute(dmod, ref attrs, id, /* needAxiom */ true);
IToken tok = theVerifyThisFile ? id : new IncludeToken(id);
if (isTwoState && isPredicate) {
f = new TwoStatePredicate(tok, id.val, dmod.IsStatic, typeArgs, formals,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, attrs, signatureEllipsis);
} else if (isTwoState) {
f = new TwoStateFunction(tok, id.val, dmod.IsStatic, typeArgs, formals, returnType,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, attrs, signatureEllipsis);
} else if (isPredicate) {
f = new Predicate(tok, id.val, dmod.IsStatic, dmod.IsProtected, !isFunctionMethod, typeArgs, formals,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, Predicate.BodyOriginKind.OriginalOrInherited, attrs, signatureEllipsis);
} else if (isIndPredicate) {
f = new InductivePredicate(tok, id.val, dmod.IsStatic, dmod.IsProtected, typeArgs, formals,
reqs, reads, ens, body, attrs, signatureEllipsis);
} else if (isCoPredicate) {
f = new CoPredicate(tok, id.val, dmod.IsStatic, dmod.IsProtected, typeArgs, formals,
reqs, reads, ens, body, attrs, signatureEllipsis);
} else {
f = new Function(tok, id.val, dmod.IsStatic, dmod.IsProtected, !isFunctionMethod, typeArgs, formals, returnType,
reqs, reads, ens, new Specification<Expression>(decreases, null), body, attrs, signatureEllipsis);
}
f.BodyStartTok = bodyStart;
f.BodyEndTok = bodyEnd;
theBuiltIns.CreateArrowTypeDecl(formals.Count);
if (isIndPredicate || isCoPredicate) {
// also create an arrow type for the corresponding prefix predicate
theBuiltIns.CreateArrowTypeDecl(formals.Count + 1);
}
}
