Expression parser. More...

#include <QtxEvalExpr.h>

Data Structures
struct	PostfixItem
	Postfix representation element. More...
Public Member Functions
	QtxEvalParser ()
	Constructor.
virtual	~QtxEvalParser ()
	Destructor.
QVariant	calculate ()
	Calculate the expression without postfix rebuilding.
QVariant	calculate (const QString &)
	Change the expression, rebuild the postfix and calculate it.
bool	setExpression (const QString &)
	Change the expression and rebuild the postfix.
QList< QtxEvalSet * >	operationSets () const
	Get current operations set.
QtxEvalSet *	operationSet (const QString &) const
	Get the operations set by name.
void	removeOperationSet (QtxEvalSet *)
	Remove the operations set.
void	insertOperationSet (QtxEvalSet *, const int=-1)
	Install the operations set.
bool	autoDeleteOperationSets () const
	Get the 'auto-delete operations' flag value.
void	setAutoDeleteOperationSets (const bool)
	Set the 'auto-delete operations' flag value.
virtual void	clearParameters ()
	Remove all parameters.
virtual bool	removeParameter (const QString &name)
	Remove parameter.
virtual QVariant	parameter (const QString &name) const
	Get the parameter value.
virtual bool	hasParameter (const QString &name) const
	Check if the parser contains specified parameter.
virtual void	setParameter (const QString &name, const QVariant &value)
	Set parameters value.
QStringList	parameters () const
	Get the list of the parameters names.
QtxEvalExpr::Error	error () const
	Get the code of the latest parsing error.
bool	firstInvalid (QString &) const
	Search first parameter with assigned invalid value.
void	removeInvalids ()
	Remove all parameters with assigned invalid values.
QString	dump () const
	Dump the current postfix contents to the string.
Static Public Member Functions
static QString	toString (const QList< QVariant > &)
	Get the string representation for the list of QVariant values.
Protected Types
enum	PostfixItemType { Value, Param, Open, Close, Pre, Post, Binary }
	Types of postfix representation elements. More...
typedef QList< PostfixItem >	Postfix
	postfix representation
typedef QList< QtxEvalSet * >	SetList
	list of operations
typedef QMap< QString, QVariant >	ParamMap
	parameter-to-value map
Protected Member Functions
QString	dump (const Postfix &) const
	Dump the postfix contents to the string.
virtual bool	prepare (const QString &, Postfix &)
	Prepare to the parsing.
virtual bool	setOperationTypes (Postfix &)
	Analyze the operations used.
virtual bool	sort (const Postfix &, Postfix &, const QStringList &, const QStringList &, int f=-1, int l=-1)
	Sort the operations in the postfix.
virtual bool	parse (const QString &)
	Parse the expression and build the posfix.
virtual void	setError (const QtxEvalExpr::Error)
	Set the error vode.
bool	calculate (const QString &, QVariant &, QVariant &)
	Calculate the operation.
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.
static QString	note (const QString &str, int pos, int len)
	Get the substring field from the string str.
static int	globalBrackets (const Postfix &, int, int)
	Get the number of the globar brackets pairs.
Private Member Functions
void	operationList (QStringList &) const
	Get names of all operations used in the expression.
void	bracketsList (QStringList &, bool) const
	Get list of brackets.
bool	createValue (const QString &, QVariant &) const
	Create value.
int	priority (const QString &, bool isBin) const
	Get the operation priority level.
QtxEvalExpr::Error	isValid (const QString &, const QVariant::Type, const QVariant::Type) const
	Check operation validity.
QtxEvalExpr::Error	calculation (const QString &, QVariant &, QVariant &) const
	Perform calculation.
bool	checkOperations () const
	Check current operations set.
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 QList<PostfixItem> QtxEvalParser.Postfix [protected]

typedef QList<QtxEvalSet*> QtxEvalParser.SetList [protected]

typedef QMap<QString, QVariant> QtxEvalParser.ParamMap [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

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::setExpression ( const QString & expr )

Parameters:

expr	new expression

Returns:: true on success and false if error is found

References parse().

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

Returns:: current operations set

References mySets.

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.

void QtxEvalParser::removeOperationSet ( QtxEvalSet * set )

Parameters:

operations set to be removed

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

References mySets.

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.

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::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::clearParameters ( ) [virtual]

References myParams.

bool QtxEvalParser::removeParameter ( const QString & name ) [virtual]

Parameters:

name	parameter name

Returns:: true on success

References myParams.

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.

bool QtxEvalParser::hasParameter ( const QString & name ) const [virtual]

Parameters:

name	parameter name

Returns:: true, if the parser contains parameter

References myParams.

void QtxEvalParser::setParameter	(	const QString &	name,
		const QVariant &	value
	)		`[virtual]`

Parameters:

name	parameter name
value	parameter value

References myParams.

QStringList QtxEvalParser::parameters ( ) const

Returns:: parameters names

References myPostfix, and Param.

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.

void QtxEvalParser::removeInvalids ( )

References myParams.

QString QtxEvalParser::dump ( ) const

Returns:: string representation of the internal parser postfix

References myPostfix.

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

Parameters:

list	list to be converted

Returns:: string representation for the list

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.

bool QtxEvalParser::prepare	(	const QString &	expr,
		Postfix &	post
	)		`[protected, virtual]`

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.

bool QtxEvalParser::setOperationTypes ( Postfix & post ) [protected, virtual]

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.

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

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, test_big_table.k, test_table.l, QtxEvalParser.PostfixItem.myType, QtxEvalParser.PostfixItem.myValue, QtxEvalExpr.OK, Open, Param, Post, Pre, priority(), setError(), and Value.

bool QtxEvalParser::parse ( const QString & expr ) [protected, virtual]

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().

void QtxEvalParser::setError ( const QtxEvalExpr::Error err ) [protected, virtual]

Parameters:

err	error code

References myError.

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().

int QtxEvalParser::search	(	const QStringList &	list,
		const QString &	str,
		int	offset,
		int &	matchLen,
		int &	listind
	)		`[static, protected]`

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

QString QtxEvalParser::note	(	const QString &	str,
		int	pos,
		int	len
	)		`[static, protected]`

Parameters:

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

Returns:: substring (leading and trailing spaces are truncated)

int QtxEvalParser::globalBrackets	(	const Postfix &	post,
		int	f,
		int	l
	)		`[static, protected]`

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, test_table.l, and Open.

void QtxEvalParser::operationList ( QStringList & list ) const [private]

Parameters:

list	returning list of the operations names

References mySets, and QtxEvalSet.operationList().

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.

bool QtxEvalParser::createValue	(	const QString &	str,
		QVariant &	val
	)		const `[private]`

Parameters:

str	parsed string
val	returning value

Returns:: true on success

References mySets.

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.

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.

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().

Field Documentation

SetList QtxEvalParser.mySets [private]

QtxEvalExpr::Error QtxEvalParser.myError [private]

ParamMap QtxEvalParser.myParams [private]

Postfix QtxEvalParser.myPostfix [private]

bool QtxEvalParser.myAutoDel [private]

QtxEvalParser Class Reference

Data Structures

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

Field Documentation