Expression parser. More...

#include <QtxEvalExpr.h>

Classes
struct	PostfixItem
	Postfix representation element. More...

Public Member Functions
	QtxEvalParser ()
	Constructor. More...

virtual	~QtxEvalParser ()
	Destructor. More...

QVariant	calculate ()
	Calculate the expression without postfix rebuilding. More...

QVariant	calculate (const QString &)
	Change the expression, rebuild the postfix and calculate it. More...

bool	setExpression (const QString &)
	Change the expression and rebuild the postfix. More...

QList< QtxEvalSet * >	operationSets () const
	Get current operations set. More...

QtxEvalSet *	operationSet (const QString &) const
	Get the operations set by name. More...

void	removeOperationSet (QtxEvalSet *)
	Remove the operations set. More...

void	insertOperationSet (QtxEvalSet *, const int=-1)
	Install the operations set. More...

bool	autoDeleteOperationSets () const
	Get the 'auto-delete operations' flag value. More...

void	setAutoDeleteOperationSets (const bool)
	Set the 'auto-delete operations' flag value. More...

virtual void	clearParameters ()
	Remove all parameters. More...

virtual bool	removeParameter (const QString &name)
	Remove parameter. More...

virtual QVariant	parameter (const QString &name) const
	Get the parameter value. More...

virtual bool	hasParameter (const QString &name) const
	Check if the parser contains specified parameter. More...

virtual void	setParameter (const QString &name, const QVariant &value)
	Set parameters value. More...

QStringList	parameters () const
	Get the list of the parameters names. More...

QtxEvalExpr::Error	error () const
	Get the code of the latest parsing error. More...

bool	firstInvalid (QString &) const
	Search first parameter with assigned invalid value. More...

void	removeInvalids ()
	Remove all parameters with assigned invalid values. More...

QString	dump () const
	Dump the current postfix contents to the string. More...

Static Public Member Functions
static QString	toString (const QList< QVariant > &)
	Get the string representation for the list of QVariant values. More...

Protected Types
enum	PostfixItemType { Value, Param, Open, Close, Pre, Post, Binary }
	Types of postfix representation elements. More...

typedef QList< PostfixItem >	Postfix
	postfix representation More...

typedef QList< QtxEvalSet * >	SetList
	list of operations More...

typedef QMap< QString, QVariant >	ParamMap
	parameter-to-value map More...

Protected Member Functions
QString	dump (const Postfix &) const
	Dump the postfix contents to the string. More...

virtual bool	prepare (const QString &, Postfix &)
	Prepare to the parsing. More...

virtual bool	setOperationTypes (Postfix &)
	Analyze the operations used. More...

virtual bool	sort (const Postfix &, Postfix &, const QStringList &, const QStringList &, int f=-1, int l=-1)
	Sort the operations in the postfix. More...

virtual bool	parse (const QString &)
	Parse the expression and build the posfix. More...

virtual void	setError (const QtxEvalExpr::Error)
	Set the error vode. More...

bool	calculate (const QString &, QVariant &, QVariant &)
	Calculate the operation. More...

Static Protected Member Functions
static int	search (const QStringList &, const QString &, int offset, int &matchLen, int &listind)
	Search elements of the list as substrings starting from offset. More...

static QString	note (const QString &str, int pos, int len)
	Get the substring field from the string str. More...

static int	globalBrackets (const Postfix &, int, int)
	Get the number of the globar brackets pairs. More...

Private Member Functions
void	operationList (QStringList &) const
	Get names of all operations used in the expression. More...

void	bracketsList (QStringList &, bool) const
	Get list of brackets. More...

bool	createValue (const QString &, QVariant &) const
	Create value. More...

int	priority (const QString &, bool isBin) const
	Get the operation priority level. More...

QtxEvalExpr::Error	isValid (const QString &, const QVariant::Type, const QVariant::Type) const
	Check operation validity. More...

QtxEvalExpr::Error	calculation (const QString &, QVariant &, QVariant &) const
	Perform calculation. More...

bool	checkOperations () const
	Check current operations set. More...

Private Attributes
SetList	mySets

QtxEvalExpr::Error	myError

ParamMap	myParams

Postfix	myPostfix

bool	myAutoDel

Detailed Description

This class provides the functionality to calculate value of the expression using defined set of operations. Standard operations (arithmetics, logic, strings, etc) are implemented in the corresponding successors of the QtxEvalSet class: QtxEvalSetArithmetic, QtxEvalSetLogic, QtxEvalSetMath, QtxEvalSetString, ...

The parser allows using parameters with help of methods has(), set(), remove(), value(). It uses postfix representation of expressions and uses class QtxEvalSet in order to make certain operation.

Every instance of parser contains only one postfix - thus, if the expression is changed, the postfix must be rebuilt. In order to increase performance of frequent calculations for many of expressions it is recommended to use different instances of the parser for each expression.

Member Typedef Documentation

typedef QMap<QString, QVariant> QtxEvalParser::ParamMap

protected

typedef QList<PostfixItem> QtxEvalParser::Postfix

protected

typedef QList<QtxEvalSet*> QtxEvalParser::SetList

protected

Member Enumeration Documentation

enum QtxEvalParser::PostfixItemType

protected

Enumerator
Value	Value (number, string, etc.)
Param	Parameter.
Open	Open bracket.
Close	Close bracket.
Pre	Unary prefix operation.
Post	Unary postfix operation.
Binary	Binary operation.

Constructor & Destructor Documentation

QtxEvalParser::QtxEvalParser ( )

References QtxEvalExpr::OK, and setError().

QtxEvalParser::~QtxEvalParser ( )

virtual

References autoDeleteOperationSets(), and mySets.

Member Function Documentation

bool QtxEvalParser::autoDeleteOperationSets ( ) const

Returns: true if all operations shoud be automatically deleted when the parser is destroyed

See Also: setAutoDeleteOperationSets()

References myAutoDel.

void QtxEvalParser::bracketsList	(	QStringList &	list,
		bool	open
	)		const

private

Parameters

list	returning list of brackets
open	if `true`, collect opening brackets, or closing brackets otherwise

References QtxEvalSet::bracketsList(), and mySets.

QVariant QtxEvalParser::calculate ( )

Returns: QVariant as result (it is invalid if there were errors during calculation)

References Binary, bracketsList(), checkOperations(), error(), QtxEvalExpr::ExcessData, hasParameter(), QtxEvalExpr::InvalidToken, myParams, myPostfix, QtxEvalExpr::OK, Param, Post, Pre, setError(), QtxEvalExpr::StackUnderflow, and Value.

QVariant QtxEvalParser::calculate ( const QString & expr )

Parameters

expr	new expression

Returns: QVariant as result (it is invalid if there were errors during calculation)

References calculate(), and setExpression().

bool QtxEvalParser::calculate	(	const QString &	op,
		QVariant &	v1,
		QVariant &	v2
	)

protected

The result of the operation is returned in the parameter v1.

Parameters

op	operation name
v1	first argument (not valid for unary prefix operations)
v2	second argument (not valid for unary postfix operations)

Returns: true on success and false if error is found

References calculation(), error(), isValid(), QtxEvalExpr::OK, and setError().

QtxEvalExpr::Error QtxEvalParser::calculation	(	const QString &	op,
		QVariant &	v1,
		QVariant &	v2
	)		const

private

The result of the operation is returned in the parameter v1. If the operation is calculated correctly, the function returns QtxEvalExpr::OK.

Parameters

op	operation name
v1	first argument (not valid for unary prefix operations)
v2	second argument (not valid for unary postfix operations)

Returns: error code (QtxEvalExpr::Error)

References QtxEvalExpr::InvalidOperation, QtxEvalExpr::InvalidResult, mySets, and QtxEvalExpr::OK.

bool QtxEvalParser::checkOperations ( ) const

private

Returns: false if current set of operations is empty

References mySets, QtxEvalExpr::OperationsNull, and setError().

void QtxEvalParser::clearParameters ( )

virtual

References myParams.

bool QtxEvalParser::createValue	(	const QString &	str,
		QVariant &	val
	)		const

private

Parameters

str	parsed string
val	returning value

Returns: true on success

References mySets.

QString QtxEvalParser::dump ( ) const

Returns: string representation of the internal parser postfix

References myPostfix.

QString QtxEvalParser::dump ( const Postfix & post ) const

protected

Parameters

post	postfix to be dumped

Returns: string representation of the postfix

References Binary, checkOperations(), Post, Pre, and Value.

QtxEvalExpr::Error QtxEvalParser::error ( ) const

Returns: last error code

References myError.

bool QtxEvalParser::firstInvalid ( QString & name ) const

Parameters

name	used to retrieve the name of the parameter if it is found

Returns: true if parameter is found

References myParams.

int QtxEvalParser::globalBrackets	(	const Postfix &	post,
		int	f,
		int	l
	)

staticprotected

For example, the expression '((2+3))' has 2 global brackets pairs.

Parameters

post	postfix to be checked
f	starting position for the search
l	last position for the search

Returns: number of brackets pairs

References Close, and Open.

bool QtxEvalParser::hasParameter ( const QString & name ) const

virtual

Parameters

name	parameter name

Returns: true, if the parser contains parameter

References myParams.

void QtxEvalParser::insertOperationSet	(	QtxEvalSet *	set,
		const int	idx = `-1`
	)

Parameters

operations	set to be added
idx	index in the list at which the operations set shoud be inserted

See Also: operationSets(), removeOperationSet(), operationSet()

References mySets.

QtxEvalExpr::Error QtxEvalParser::isValid	(	const QString &	op,
		const QVariant::Type	t1,
		const QVariant::Type	t2
	)		const

private

If the operation is valid, QtxEvalExpr::OK is returned.

Parameters

op	operation
t1	first operand type
t2	second operand type

Returns: error code (QtxEvalExpr::Error)

References mySets, and QtxEvalExpr::OK.

QString QtxEvalParser::note	(	const QString &	str,
		int	pos,
		int	len
	)

staticprotected

Parameters

str	source string
pos	start position of the substring
len	length of the substring

Returns: substring (leading and trailing spaces are truncated)

void QtxEvalParser::operationList ( QStringList & list ) const

private

Parameters

list	returning list of the operations names

References mySets, and QtxEvalSet::operationList().

QtxEvalSet * QtxEvalParser::operationSet ( const QString & name ) const

Parameters

name	the name of the operation set

Returns: operation set or 0 if not found

References mySets.

QList< QtxEvalSet * > QtxEvalParser::operationSets ( ) const

Returns: current operations set

References mySets.

QVariant QtxEvalParser::parameter ( const QString & name ) const

virtual

Parameters

name	parameter name

Returns: parameter value or invalud QVariant if there is no such parameter

References myParams.

QStringList QtxEvalParser::parameters ( ) const

Returns: parameters names

References myPostfix, and Param.

bool QtxEvalParser::parse ( const QString & expr )

protectedvirtual

If by parsing error is found, the function returns false. In this case the code of the error can be retrieved with error() method.

Parameters

expr	string expression

Returns: true on success and false if error is found

References bracketsList(), checkOperations(), myPostfix, QtxEvalExpr::OK, prepare(), setError(), setOperationTypes(), and sort().

bool QtxEvalParser::prepare	(	const QString &	expr,
		Postfix &	post
	)

protectedvirtual

Performs the first step of the parsing:

find tokens
determine tokens types
create unsorted pseudo-postfix (with brackets)

Parameters

expr	string expression
post	postfix to be created

Returns: true on success and false if error is found

References Binary, bracketsList(), QtxEvalExpr::BracketsNotMatch, checkOperations(), Close, QtxEvalExpr::CloseExpected, createValue(), error(), QtxEvalExpr::ExcessClose, QtxEvalParser::PostfixItem::myType, QtxEvalParser::PostfixItem::myValue, note(), QtxEvalExpr::OK, Open, operationList(), Param, search(), setError(), and Value.

int QtxEvalParser::priority	(	const QString &	op,
		bool	isBin
	)		const

private

Parameters

op	operation
isBin	`true` if the operation is binary and `false` if it is unary

Returns: operation priority

References mySets.

void QtxEvalParser::removeInvalids ( )

References myParams.

void QtxEvalParser::removeOperationSet ( QtxEvalSet * set )

Parameters

operations set to be removed

See Also: operationSets(), insertOperationSet(), operationSet()

References mySets.

bool QtxEvalParser::removeParameter ( const QString & name )

virtual

Parameters

name	parameter name

Returns: true on success

References myParams.

int QtxEvalParser::search	(	const QStringList &	list,
		const QString &	str,
		int	offset,
		int &	matchLen,
		int &	listind
	)

staticprotected

Parameters

list	list of substrings
str	string in which the searching is performed
offset	starting index for search
matchLen	returning matching length of any substring
listind	returning index of the found substring in the list

Returns: position of first found substring inside the str or -1 if no matches is found

void QtxEvalParser::setAutoDeleteOperationSets ( const bool on )

Parameters

on	if `true`, all operations shoud be automatically deleted when the parser is destroyed

See Also: autoDeleteOperationSets()

References myAutoDel.

void QtxEvalParser::setError ( const QtxEvalExpr::Error err )

protectedvirtual

Parameters

err	error code

References myError.

bool QtxEvalParser::setExpression ( const QString & expr )

Parameters

expr	new expression

Returns: true on success and false if error is found

References parse().

bool QtxEvalParser::setOperationTypes ( Postfix & post )

protectedvirtual

Second step of the parsing: analyze the types of the operations used in the expression.

Parameters

post	unsorted postfix

Returns: true on success and false if error is found

References Binary, bracketsList(), checkOperations(), Close, error(), QtxEvalExpr::OK, Open, Param, Post, Pre, and Value.

void QtxEvalParser::setParameter	(	const QString &	name,
		const QVariant &	value
	)

virtual

Parameters

name	parameter name
value	parameter value

References myParams.

bool QtxEvalParser::sort	(	const Postfix &	post,
		Postfix &	res,
		const QStringList &	anOpen,
		const QStringList &	aClose,
		int	f = `-1`,
		int	l = `-1`
	)

protectedvirtual

Third step of parsing: sort the postfix operations in order to convert it to real postfix.

Parameters

post	source postfix
res	returning resulting postfix
anOpen	list of open brackets
aClose	list of close brackets
f	start index of postfix for sorting
l	last index of postfix for sorting

Returns: true on success and false if error is found

References Binary, checkOperations(), Close, QtxEvalExpr::CloseExpected, error(), globalBrackets(), QtxEvalExpr::InvalidOperation, QtxEvalParser::PostfixItem::myType, QtxEvalParser::PostfixItem::myValue, QtxEvalExpr::OK, Open, Param, Post, Pre, priority(), setError(), and Value.

QString QtxEvalParser::toString ( const QList< QVariant > & list )

static

Parameters

list	list to be converted

Returns: string representation for the list

Member Data Documentation

bool QtxEvalParser::myAutoDel

private

QtxEvalExpr::Error QtxEvalParser::myError

private

ParamMap QtxEvalParser::myParams

private

Postfix QtxEvalParser::myPostfix

private

SetList QtxEvalParser::mySets

private

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

src/Qtx/QtxEvalExpr.h
src/Qtx/QtxEvalExpr.cxx

Classes

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Static Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation