Converter for math equations. More...

#include <InfixToPostfix.h>

Inheritance diagram for Isis::InfixToPostfix:

Collaboration diagram for Isis::InfixToPostfix:

Public Member Functions
	InfixToPostfix ()
	Constructor.

QString	convert (const QString &infix)
	This method converts infix to postfix.

QString	tokenizeEquation (const QString &equation)
	This method will add spaces between all operators and numbers, making it possible to get each element of the equation one by one.

Protected Member Functions
virtual bool	isKnownSymbol (QString representation)
	This method will return true if it believes the argument represents a valid function or operator.

virtual InfixOperator *	findOperator (QString representation)
	This method will return a pointer to the operator represented by 'representation.

Protected Attributes
QList< InfixOperator * >	p_operators

Private Member Functions
void	initialize ()
	This populates the known operators/functions list.

void	uninitialize ()
	This cleans the known operators/functions list.

QString	formatFunctionCalls (QString equation)
	This method looks through equation for function calls, parenthesizes them, and calls itself again with each argument in order to parse any embedded functions.

QString	cleanSpaces (QString equation)
	This function takes a space-delimited string and removes empty delimiters.

void	closeParenthesis (QString &postfix, std::stack< InfixOperator > &theStack)
	This is straight from the algorithm found on page 159 of "Data Structures & Algorithms in Java" Second Edition by Robert Lafore.

void	addOperator (QString &postfix, const InfixOperator &op, std::stack< InfixOperator > &theStack)
	This is straight from the algorithm found on page 159 of "Data Structures & Algorithms in Java" Second Edition by Robert Lafore.

bool	isFunction (QString representation)
	This method will return true if 'representation' is a known function.

void	checkArgument (QString funcName, int argNum, QString argument)

Detailed Description

Converter for math equations.

This class converts infix equations to postfix

Author: 2007-08-21 Steven Lambright

History:

2007-08-22 Steven Lambright - Changed p_operators from vector to QList (static std::vector is unsafe)

2008-01-23 Steven Lambright - Added the operators (constants) PI and e

2010-02-23 Steven Lambright - Operator/Function input strings and output strings now separated

2010-04-08 Steven Lambright - Min, max functions expanded upon

2012-01-09 Jeff Anderson - Modified to conform ISIS programming standards

Definition at line 57 of file InfixToPostfix.h.

Constructor & Destructor Documentation

Isis::InfixToPostfix::InfixToPostfix ( )

Constructor.

Definition at line 34 of file InfixToPostfix.cpp.

Member Function Documentation

void Isis::InfixToPostfix::addOperator	(	QString &	postfix,
		const InfixOperator &	op,
		std::stack< InfixOperator > &	theStack
	)

private

This is straight from the algorithm found on page 159 of "Data Structures & Algorithms in Java" Second Edition by Robert Lafore.

Parameters

postfix	The postix generated thus far
op	The operator
theStack	The operator stack

Definition at line 302 of file InfixToPostfix.cpp.

QString Isis::InfixToPostfix::cleanSpaces ( QString equation )

private

This function takes a space-delimited string and removes empty delimiters.

In order words, it compresses the spaces. This is used to keep strings small, clean, and remove the necessity to check for empty tokens constantly.

That is, if your string is "a b" the result will be "a b".

Parameters

equation A space-delimited string with excessive spaces

Returns: IString A space-delimited string with data between every pair of spaces

Definition at line 124 of file InfixToPostfix.cpp.

References Isis::IString::Token(), and Isis::IString::ToQt().

void Isis::InfixToPostfix::closeParenthesis	(	QString &	postfix,
		std::stack< InfixOperator > &	theStack
	)

private

This is straight from the algorithm found on page 159 of "Data Structures & Algorithms in Java" Second Edition by Robert Lafore.

Parameters

postfix	The postix generated thus far
theStack	The operator stack

Definition at line 331 of file InfixToPostfix.cpp.

References _FILEINFO_.

QString Isis::InfixToPostfix::convert ( const QString & infix )

This method converts infix to postfix.

It uses an enhanced verion of the algorithm found on page 159 of "Data Structures & Algorithms in Java" Second Edition by Robert Lafore. First, we prep the equation with TokenizeEquation and then parse through it using the known-good algorithm.

Parameters

infix The infix equation

Returns: IString The postfix equation

Definition at line 154 of file InfixToPostfix.cpp.

References _FILEINFO_, Isis::IString::Remove(), Isis::toDouble(), Isis::IString::Token(), and Isis::IString::ToQt().

InfixOperator * Isis::InfixToPostfix::findOperator ( QString representation )

protectedvirtual

This method will return a pointer to the operator represented by 'representation.

' Because in this model a function is an operator, this will return a pointer to functions as well (in a base class pointer).

Parameters

representation The symbolic representation of the operator, such as '+'

Returns: InfixOperator* A pointer to the operator object that contains known information about the operator

Reimplemented in Isis::CubeInfixToPostfix.

Definition at line 362 of file InfixToPostfix.cpp.

References _FILEINFO_.

QString Isis::InfixToPostfix::formatFunctionCalls ( QString equation )

private

This method looks through equation for function calls, parenthesizes them, and calls itself again with each argument in order to parse any embedded functions.

This ensures order of operations holds for cases like sin(.5)^2. This method might add too many parentheses, but that is harmless. This does not affect operators (excepting –) or numbers. Only functions. The input should be space-delimited.

Parameters

equation The unparenthesized equation

Returns: IString The parenthesized equation

This code block is for multi-parameter functions. Functions with 1+ parameters are parsed here, excepting the negation (with no parentheses) which is done just above.

We figure out the arguments by looking for commas, outside of all parentheses, for each argument up until the last one. We look for an extra closing parenthesis for the last argument. When we figure out what an argument is, we recursively call FormatFunctionCalls to format any and all functionality inside of the argument.

Definition at line 485 of file InfixToPostfix.cpp.

References _FILEINFO_, Isis::IString::Token(), and Isis::IString::ToQt().

void Isis::InfixToPostfix::initialize ( )

private

This populates the known operators/functions list.

If the operators list is not empty, this function will do nothing.

Definition at line 46 of file InfixToPostfix.cpp.

bool Isis::InfixToPostfix::isFunction ( QString representation )

private

This method will return true if 'representation' is a known function.

Parameters

representation The symbolic representation of a function, such as 'abs'

Returns: bool True if it's a known function, false otherwise

Definition at line 285 of file InfixToPostfix.cpp.

bool Isis::InfixToPostfix::isKnownSymbol ( QString representation )

protectedvirtual

This method will return true if it believes the argument represents a valid function or operator.

Parameters

representation The symbolic representation of the operator, such as 'sin'

Returns: bool True if it looks valid, false if it's not known

Reimplemented in Isis::CubeInfixToPostfix.

Definition at line 268 of file InfixToPostfix.cpp.

QString Isis::InfixToPostfix::tokenizeEquation ( const QString & equation )

This method will add spaces between all operators and numbers, making it possible to get each element of the equation one by one.

It will also parse out the function calls, adding parenthesis where needed so the user doesn't have to. The result is an equation ready for parsing (but NOT fully parenthesized, just enough to make sure our algorithm makes no mistakes).

Parameters

equation An unformatted infix equation

Returns: IString A tokenized equation with additional parentheses

Definition at line 384 of file InfixToPostfix.cpp.

References Isis::IString::DownCase(), and Isis::IString::ToQt().

void Isis::InfixToPostfix::uninitialize ( )

private

This cleans the known operators/functions list.

Definition at line 104 of file InfixToPostfix.cpp.

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

src/base/objs/InfixToPostfix/InfixToPostfix.h
src/base/objs/InfixToPostfix/InfixToPostfix.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation