Recursive-descent parser. More...

#include <RDparser.h>

Inheritance diagram for utl::RDparser:

Public Member Functions
virtual void	copy (const Object &rhs)
	Copy another instance. More...

void	addProduction (uint_t id, const String &name, const String &rhs)
	Add a production rule. More...

void	addTerminal (uint_t id, const String &name, const String &regex)
	Add a terminal symbol. More...

bool	compile ()
	Compile the state machine to parse the grammar. More...

bool	ok () const
	Determine whether a properly defined grammar has been compiled. More...

Graph *	parse (Stream &stream, const String *prod=nullptr)
	Parse text from the given stream until EOF. More...

Graph *	parse (const String &str, const String *prod=nullptr)
	Parse the given string. More...

Public Member Functions inherited from utl::Object
void	clear ()
	Revert to initial state. More...

virtual int	compare (const Object &rhs) const
	Compare with another object. More...

virtual void	vclone (const Object &rhs)
	Make an exact copy of another instance. More...

virtual void	steal (Object &rhs)
	"Steal" the internal representation from another instance. More...

virtual void	dump (Stream &os, uint_t level=uint_t_max) const
	Dump a human-readable representation of self to the given output stream. More...

void	dumpWithClassName (Stream &os, uint_t indent=4, uint_t level=uint_t_max) const
	Front-end for dump() that prints the object's class name. More...

virtual const Object &	getKey () const
	Get the key for this object. More...

bool	hasKey () const
	Determine whether or not the object has a key. More...

virtual const Object &	getProxiedObject () const
	Get the proxied object (= self if none). More...

virtual Object &	getProxiedObject ()
	Get the proxied object (= self if none). More...

virtual size_t	hash (size_t size) const
	Get the hash code for the object. More...

bool	_isA (const RunTimeClass *runTimeClass) const
	Determine whether self's class is a descendent of the given class. More...

virtual String	toString () const
	Return a string representation of self. More...

	operator String () const
	Conversion to String. More...

size_t	allocatedSize () const
	Get the total allocated size of this object. More...

virtual size_t	innerAllocatedSize () const
	Get the "inner" allocated size. More...

virtual void	addOwnedIt (const class FwdIt *it) const
	Notify self that it owns the given iterator. More...

virtual void	removeOwnedIt (const class FwdIt *it) const
	Notify self that the given owned iterator has been destroyed. More...

bool	operator< (const Object &rhs) const
	Less-than operator. More...

bool	operator<= (const Object &rhs) const
	Less-than-or-equal-to operator. More...

bool	operator> (const Object &rhs) const
	Greater-than operator. More...

bool	operator>= (const Object &rhs) const
	Greater-than-or-equal-to operator. More...

bool	operator== (const Object &rhs) const
	Equal-to operator. More...

bool	operator!= (const Object &rhs) const
	Unequal-to operator. More...

void	serializeIn (Stream &is, uint_t mode=ser_default)
	Serialize from an input stream. More...

void	serializeOut (Stream &os, uint_t mode=ser_default) const
	Serialize to an output stream. More...

virtual void	serialize (Stream &stream, uint_t io, uint_t mode=ser_default)
	Serialize to or from a stream. More...

void	serializeOutBoxed (Stream &os, uint_t mode=ser_default) const
	Serialize a boxed object to an output stream. More...

Additional Inherited Members
Static Public Member Functions inherited from utl::Object
static Object *	serializeInNullable (Stream &is, uint_t mode=ser_default)
	Serialize a nullptr-able object from an input stream. More...

static void	serializeOutNullable (const Object *object, Stream &os, uint_t mode=ser_default)
	Serialize a nullptr-able object to an output stream. More...

static void	serializeNullable (Object *&object, Stream &stream, uint_t io, uint_t mode=ser_default)
	Serialize a nullptr-able object to or from a stream. More...

static Object *	serializeInBoxed (Stream &is, uint_t mode=ser_default)
	Serialize a boxed object from an input stream. More...

static void	serializeBoxed (Object *&object, Stream &stream, uint_t io, uint_t mode=ser_default)
	Serialize a boxed object to or from a stream. More...

Protected Member Functions inherited from utl::FlagsMI
	FlagsMI ()
	Constructor. More...

virtual	~FlagsMI ()
	Destructor. More...

void	copyFlags (const FlagsMI &rhs)
	Copy the given flags. More...

void	copyFlags (const FlagsMI &rhs, uint_t lsb, uint_t msb)
	Copy (some of) the given flags. More...

void	copyFlags (uint64_t flags, uint_t lsb, uint_t msb)
	Copy (some of) the given flags. More...

bool	getFlag (uint_t flagNum) const
	Get a user-defined flag. More...

void	setFlag (uint_t flagNum, bool val)
	Set a user-defined flag. More...

uint64_t	getFlagsNumber (uint64_t mask, uint64_t shift=0)
	Get a multi-bit value in the flags data (which is stored as one 64-bit integer). More...

void	setFlagsNumber (uint64_t mask, uint64_t shift, uint64_t num)
	Set a multi-bit value in the flags data (which is stored as one 64-bit integer). More...

uint64_t	getFlags () const
	Get the flags. More...

void	setFlags (uint64_t flags)
	Set the flags. More...

Detailed Description

Recursive-descent parser.

This is a fairly simple parser that should be adequate for many purposes. RDparser allows you to define a grammar and then parse text that satisfies the grammar. A grammar is defined by its productions and terminals.

Productions

A grammar production describes a rule for translating a production symbol into one or more production or terminal symbols. A production symbol may also be referred to as a non-terminal symbol.

The rules for writing a valid grammar production are themselves best described by writing a grammar, but don't worry I'll try to make it clear!

PRODUCTION ::= BRANCH { \| BRANCH }
BRANCH     ::= ATOM { ATOM }
ATOM       ::= PRODUCTION
             | TERMINAL
             | \[ PRODUCTION \]
             | \{ PRODUCTION \}

Let's examine each of these three productions:

A PRODUCTION consists of a BRANCH followed by zero or more additional BRANCHes.
A BRANCH consists of an ATOM followed by zero or more additional ATOMs.
An ATOM consists of one of the following:
1. a PRODUCTION
2. a TERMINAL
3. open-square-bracket PRODUCTION close-square-bracket
4. open-curly-bracket PRODUCTION close-curly-bracket

As you can see:

Symbols enclosed in square brackets must be matched zero or one times.
Symbols enclosed in curly brackets must be matched zero or more times.
A symbol can be escaped with the '\' character to suppress its normal meaning. The ATOM production contains examples of this. The square and curly brackets had to be escaped otherwise the rule's meaning is rather different, given that those symbols carry special meaning in the grammar for writing production rules.
The '|' character separates multiple possible translations, any of which can satisfy the production rule.

Left-recursion is not supported. That is, you cannot write a production rule whose first symbol is the name of the production itself.

Terminals

At some point we have to describe the actual characters we expect to see. The "leaves" of the grammar consist of terminal symbols which are specified by regular expressions (Regex). For example, you might have a terminal symbol to represent a number, with a regular expression like "\\d+(\\.\\d*)?".

General Instructions

After defining the grammar by defining productions (addProduction()) and terminals (addTerminal()), call compile() to create the state machine that will be used to parse the grammar. Then you're ready to parse text (parse()). To see a full example of RDparser in action, look at the example program that parses simple math expressions.

Author: Adam McKee

Definition at line 103 of file RDparser.h.

Member Function Documentation

◆ copy()

virtual void utl::RDparser::copy ( const Object & rhs )

virtual

Copy another instance.

When you override copy(), you should usually call the superclass's copy().

Parameters

rhs	object to copy

Reimplemented from utl::Object.

◆ addProduction()

void utl::RDparser::addProduction	(	uint_t	id,
		const String &	name,
		const String &	rhs
	)

Add a production rule.

Parameters

id	unique production rule id
name	production name
rhs	right-hand-side of production

◆ addTerminal()

void utl::RDparser::addTerminal	(	uint_t	id,
		const String &	name,
		const String &	regex
	)

Add a terminal symbol.

Parameters

id	unique terminal symbol id
name	terminal name
regex	regular expression for terminal

◆ compile()

bool utl::RDparser::compile ( )

Compile the state machine to parse the grammar.

Returns: true if compilation successful, false otherwise

◆ ok()

bool utl::RDparser::ok ( ) const

inline

Determine whether a properly defined grammar has been compiled.

Returns: true if grammar compiled successfully, false otherwise

Definition at line 139 of file RDparser.h.

References utl::deInit(), and utl::init().

◆ parse() [1/2]

Graph* utl::RDparser::parse	(	Stream &	stream,
		const String *	prod = `nullptr`
	)

Parse text from the given stream until EOF.

Returns: parse tree (Graph of ParseNode)

Parameters

stream	input stream
prod	(optional) root production

◆ parse() [2/2]

Graph* utl::RDparser::parse	(	const String &	str,
		const String *	prod = `nullptr`
	)

Parse the given string.

Returns: parse tree (Graph of ParseNode)

Parameters

str	input string
prod	(optional) root production

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

RDparser.h

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ copy()

◆ addProduction()

◆ addTerminal()

◆ compile()

◆ ok()

◆ parse() [1/2]

◆ parse() [2/2]