QPatternist::FunctionSignature Class Reference

Represents the signature of an XPath function. More...

#include <qfunctionsignature_p.h>

Inheritance diagram for QPatternist::FunctionSignature:

Public Types
enum	{ UnlimitedArity = -1 }
typedef qint16	Arity
typedef QHash< QXmlName, FunctionSignature::Ptr >	Hash
typedef QList< FunctionSignature::Ptr >	List
typedef QExplicitlySharedDataPointer< FunctionSignature >	Ptr
Public Types inherited from QPatternist::CallTargetDescription
typedef QList< Ptr >	List
typedef QExplicitlySharedDataPointer< CallTargetDescription >	Ptr

Public Functions
void	appendArgument (const QXmlName::LocalNameCode name, const SequenceType::Ptr &type)
FunctionArgument::List	arguments () const
QString	displayName (const NamePool::Ptr &np) const
	FunctionSignature (const QXmlName name, const Arity minArgs, const Arity maxArgs, const SequenceType::Ptr &returnType, const Expression::Properties chars=Expression::Properties(), const Expression::ID id=Expression::IDIgnorableExpression)
Expression::ID	id () const
bool	isArityValid (const xsInteger arity) const
Arity	maximumArguments () const
Arity	minimumArguments () const
bool	operator== (const FunctionSignature &other) const
Expression::Properties	properties () const
SequenceType::Ptr	returnType () const
void	setArguments (const FunctionArgument::List &args)
Public Functions inherited from QPatternist::CallTargetDescription
	CallTargetDescription (const QXmlName &name)
QXmlName	name () const
Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...
	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...

Properties
FunctionArgument::List	m_arguments
const Expression::ID	m_id
const Arity	m_maxArgs
const Arity	m_minArgs
const Expression::Properties	m_props
const SequenceType::Ptr	m_returnType

Additional Inherited Members
Static Public Functions inherited from QPatternist::CallTargetDescription
static void	checkCallsiteCircularity (CallTargetDescription::List &signList, const Expression::Ptr expr)
Public Variables inherited from QSharedData
QAtomicInt	ref

Detailed Description

Represents the signature of an XPath function.

FunctionSignature represents and allows inspection of a function signature, such as fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string. No XPath related languages allows polymorphism on the type of the arguments, only the amount(arity) of the arguments. For example, fn:string() as xs:string and fn:string($arg as item()?) as xs:string can happily co-exist, but fn:string($arg as item()?) as xs:string and fn:string($arg as xs:anyAtomicType?) as xs:string would be an error. This fact is reflected by FunctionSignature that if minimumArguments() and maximumArguments() are not equal, it means that this FunctionSignature represents several function signatures.

See also

XQuery 1.0 and XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions

Wikipedia, the free encyclopedia, Arity

Author

Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 93 of file qfunctionsignature_p.h.

Typedefs

Arity

typedef qint16 QPatternist::FunctionSignature::Arity

A number which tells the amount of arguments a function has.

Definition at line 111 of file qfunctionsignature_p.h.

Hash

typedef QHash<QXmlName, FunctionSignature::Ptr> QPatternist::FunctionSignature::Hash

Definition at line 105 of file qfunctionsignature_p.h.

List

typedef QList<FunctionSignature::Ptr> QPatternist::FunctionSignature::List

Definition at line 106 of file qfunctionsignature_p.h.

Ptr

typedef QExplicitlySharedDataPointer<FunctionSignature> QPatternist::FunctionSignature::Ptr

Definition at line 104 of file qfunctionsignature_p.h.

Enumerations

anonymous enum

anonymous enum

Enumerator
UnlimitedArity	Flags the function as allowing an unlimited amount of arguments.

Definition at line 96 of file qfunctionsignature_p.h.

        {
            UnlimitedArity = -1
        };

Constructors and Destructors

FunctionSignature()

FunctionSignature::FunctionSignature	(	const QXmlName	name,
		const Arity	minArgs,
		const Arity	maxArgs,
		const SequenceType::Ptr &	returnType,
		const Expression::Properties	chars = Expression::Properties(),
		const Expression::ID	id = Expression::IDIgnorableExpression
	)

Definition at line 50 of file qfunctionsignature.cpp.

                                                             : CallTargetDescription(nameP)
                                                               , m_minArgs(minArgs)
                                                               , m_maxArgs(maxArgs)
                                                               , m_returnType(returnTypeP)
                                                               , m_arguments()
                                                               , m_props(props)
                                                               , m_id(idP)
{
    Q_ASSERT(minArgs <= maxArgs || maxArgs == FunctionSignature::UnlimitedArity);
    Q_ASSERT(m_maxArgs >= -1);
    Q_ASSERT(returnTypeP);
}

Functions

appendArgument()

void FunctionSignature::appendArgument	(	const QXmlName::LocalNameCode	name,
		const SequenceType::Ptr &	type
	)

This is a convenience function. Calling this once, is equal to calling setArguments() with a list containing a FunctionsArgument with name name and type type.

Definition at line 68 of file qfunctionsignature.cpp.

Referenced by QPatternist::XPath10CoreFunctions::retrieveFunctionSignature(), QPatternist::XSLT20CoreFunctions::retrieveFunctionSignature(), and QPatternist::XPath20CoreFunctions::retrieveFunctionSignature().

{
    Q_ASSERT(type);

    m_arguments.append(FunctionArgument::Ptr(new FunctionArgument(QXmlName(StandardNamespaces::empty, nameP), type)));
}

arguments()

FunctionArgument::List FunctionSignature::arguments

(

)

const

Definition at line 123 of file qfunctionsignature.cpp.

Referenced by QPatternist::UserFunctionCallsite::expectedOperandTypes(), and QPatternist::ErrorFN::signature().

{
    return m_arguments;
}

displayName()

QString FunctionSignature::displayName

(

const NamePool::Ptr &

np

)

const

Builds a string representation for this function signature. The syntax used is the one used in the XQuery. It looks like this:

prefix:function-name($parameter-name as parameter-type, ...) as return-type

The prefix used for the name is conventional. For example, for constructor functions is xs used.

See also

XQuery 1.0 and XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions

Definition at line 76 of file qfunctionsignature.cpp.

{
    QString result;
    result += np->displayName(name());
    result += QLatin1Char('(');

    FunctionArgument::List::const_iterator it(m_arguments.constBegin());
    const FunctionArgument::List::const_iterator end(m_arguments.constEnd());

    if(it != end)
    {
        while(true)
        {
            result += QLatin1Char('$');
            result += np->displayName((*it)->name());
            result += QLatin1String(" as ");
            result += (*it)->type()->displayName(np);

            ++it;
            if(it == end)
                break;

            result += QLatin1String(", ");
        }
    }

    if(m_maxArgs == FunctionSignature::UnlimitedArity)
        result += QLatin1String(", ...");

    result += QLatin1String(") as ");
    result += m_returnType->displayName(np);

    return result;
}

id()

Expression::ID FunctionSignature::id

(

)

const

The ID that the corresponding FunctionCall instance should return in Expression::id().

Definition at line 153 of file qfunctionsignature.cpp.

Referenced by QPatternist::FunctionCall::id().

{
    return m_id;
}

isArityValid()

bool FunctionSignature::isArityValid

(

const xsInteger

arity

)

const

Checks whether arity is within the range of allowed count of arguments. For example, when the minimum arguments is 1 and maximum arguments 2, false will be returned for passing 0 while true will be returned when 2 is passed.

Definition at line 128 of file qfunctionsignature.cpp.

Referenced by QPatternist::FunctionFactory::isAvailable(), QPatternist::UserFunctionCallsite::isSignatureValid(), and operator==().

{
    return arity >= m_minArgs && arity <= m_maxArgs;
}

maximumArguments()

FunctionSignature::Arity FunctionSignature::maximumArguments

(

)

const

Definition at line 138 of file qfunctionsignature.cpp.

Referenced by operator==(), QPatternist::ErrorFN::signature(), QPatternist::FunctionCall::typeCheck(), and QPatternist::AbstractFunctionFactory::verifyArity().

{
    return m_maxArgs;
}

minimumArguments()

FunctionSignature::Arity FunctionSignature::minimumArguments

(

)

const

Definition at line 133 of file qfunctionsignature.cpp.

Referenced by operator==(), QPatternist::ErrorFN::signature(), and QPatternist::AbstractFunctionFactory::verifyArity().

{
    return m_minArgs;
}

operator==()

bool FunctionSignature::operator==

(

const FunctionSignature &

other

)

const

Determines whether this FunctionSignature is equal to other, taking into account XPath's function polymorphism. other is equal to this FunctionSignature if their name() instances are equal, and that the maximumArguments() and minimumArguments() arguments of other are allowed, as per isArityValid().

In other words, this equalness operator can return true for different signatures, but it do make sense since a FunctionSignature can represent multiple signatures.

Returns

true if this FunctionSignature is equal to other, otherwise false

Definition at line 111 of file qfunctionsignature.cpp.

{
    return name() == other.name() &&
           isArityValid(other.maximumArguments()) &&
           isArityValid(other.minimumArguments());
}

properties()

Expression::Properties FunctionSignature::properties

(

)

const

The properties that the corresponding FunctionCall instance should return in Expression::properties().

Definition at line 148 of file qfunctionsignature.cpp.

Referenced by QPatternist::FunctionCall::properties(), and QPatternist::ErrorFN::signature().

{
    return m_props;
}

returnType()

SequenceType::Ptr FunctionSignature::returnType

(

)

const

The return type of this function signature. For example, if the represented function signature is fn:string() as xs:string, the return type is xs:string.

Definition at line 143 of file qfunctionsignature.cpp.

Referenced by QPatternist::ErrorFN::signature(), and QPatternist::FunctionCall::staticType().

{
    return m_returnType;
}

setArguments()

void FunctionSignature::setArguments

(

const FunctionArgument::List &

args

)

Definition at line 118 of file qfunctionsignature.cpp.

{
    m_arguments = args;
}

Properties

m_arguments

FunctionArgument::List QPatternist::FunctionSignature::m_arguments

private

Definition at line 193 of file qfunctionsignature_p.h.

Referenced by appendArgument(), arguments(), displayName(), and setArguments().

m_id

const Expression::ID QPatternist::FunctionSignature::m_id

private

Definition at line 195 of file qfunctionsignature_p.h.

Referenced by id().

m_maxArgs

const Arity QPatternist::FunctionSignature::m_maxArgs

private

Definition at line 191 of file qfunctionsignature_p.h.

Referenced by displayName(), FunctionSignature(), isArityValid(), and maximumArguments().

m_minArgs

const Arity QPatternist::FunctionSignature::m_minArgs

private

Definition at line 190 of file qfunctionsignature_p.h.

Referenced by isArityValid(), and minimumArguments().

m_props

const Expression::Properties QPatternist::FunctionSignature::m_props

private

Definition at line 194 of file qfunctionsignature_p.h.

Referenced by properties().

m_returnType

const SequenceType::Ptr QPatternist::FunctionSignature::m_returnType

private

Definition at line 192 of file qfunctionsignature_p.h.

Referenced by displayName(), and returnType().

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The documentation for this class was generated from the following files:

• /src/xmlpatterns/functions/qfunctionsignature_p.h
• /src/xmlpatterns/functions/qfunctionsignature.cpp