Package com.gengoai.parsing

Class Grammar

java.lang.Object

com.gengoai.parsing.Grammar

All Implemented Interfaces:

Serializable

public class Grammar
extends Object
implements Serializable

A grammar representing the rules for parsing. Rules are defined using ParserHandlers, which are associated with individual Tags. There are two main types of handlers, prefix and postfix. The PrefixHandler takes care of prefix operators and the PostfixHandler handles infix and postfix operators.

By default a grammar will throw a ParseException when it encounters a token type that it does not know how to handle. Grammars can be set to instead ignore these tokens.

Author:

David B. Bracewell

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
Grammar()
Grammar(@NonNull GrammarRegistrable... registrables)

Method Summary

Modifier and Type	Method	Description
Optional<PostfixHandler>	getPostfixHandler(ParserToken token)	Gets the postfix handler associated with the Tag of the given ParserToken
Optional<PostfixHandler>	getPostfixHandler(Tag tag)	Gets the postfix handler associated with the given Tag.
Optional<PrefixHandler>	getPrefixHandler(ParserToken token)	Gets the prefix handler associated with the Tag of the given ParserToken
Optional<PrefixHandler>	getPrefixHandler(Tag tag)	Gets the prefix handler associated with the given Tag.
boolean	isIgnored(ParserToken token)	Checks if the given token should be ignored during parsing
boolean	isIgnored(Tag tag)	Checks if the given tag should be ignored during parsing
Grammar	postfix(Tag tag, PostfixHandler handler)	Registers a PostfixHandler with a precedence of 1 for the given Tag
Grammar	postfix(Tag tag, PostfixHandler handler, int precedence)	Registers a PostfixHandler with the given precedence for the given Tag
<E extends Expression> Grammar	postfix(Tag tag, PostfixHandler handler, int precedence, SerializablePredicate<E> validator)	Registers a PostfixHandler with the given precedence for the given Tag
int	precedenceOf(ParserToken token)	Determines the precedence of the Tag of the given ParserToken
int	precedenceOf(Tag tag)	Determines the precedence of the given tag
Grammar	prefix(Tag tag, PrefixHandler handler)	Registers a PrefixHandler for the given Tag
<E extends Expression> Grammar	prefix(Tag tag, PrefixHandler handler, SerializablePredicate<E> validator)	Registers a PrefixHandler for the given Tag
Grammar	skip(Tag tag)	Registers the given Tag as one which should be skipped during parsing.
void	validatePostfix(Expression expression)	Validates the given expression as if it were generated from a postfix handler.
void	validatePrefix(Expression expression)	Validates the given expression as if it were generated from a prefix handler.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Grammar

public Grammar()

Grammar

public Grammar(@NonNull
               @NonNull GrammarRegistrable... registrables)

Method Detail

getPostfixHandler

public Optional<PostfixHandler> getPostfixHandler(ParserToken token)

Gets the postfix handler associated with the Tag of the given ParserToken

Parameters:

token - the token to use to determine the correct PostfixHandler to retrieve

Returns:

An Optional containing the postfix handler if available or empty if none are available

getPostfixHandler

public Optional<PostfixHandler> getPostfixHandler(Tag tag)

Gets the postfix handler associated with the given Tag.

Parameters:

tag - the tag representing the operator / value for which we want to retrieve a PostfixHandler

Returns:

An Optional containing the postfix handler if available or empty if none are available

getPrefixHandler

public Optional<PrefixHandler> getPrefixHandler(ParserToken token)

Gets the prefix handler associated with the Tag of the given ParserToken

Parameters:

token - the token to use to determine the correct PrefixHandler to retrieve

Returns:

An Optional containing the prefix handler if available or empty if none are available

getPrefixHandler

public Optional<PrefixHandler> getPrefixHandler(Tag tag)

Gets the prefix handler associated with the given Tag.

Parameters:

tag - the tag representing the operator / value for which we want to retrieve a PrefixHandler

Returns:

An Optional containing the postfix handler if available or empty if none are available

isIgnored

public boolean isIgnored(ParserToken token)

Checks if the given token should be ignored during parsing

Parameters:

token - the token

Returns:

True - if should be ignored, False otherwise

isIgnored

public boolean isIgnored(Tag tag)

Checks if the given tag should be ignored during parsing

Parameters:

tag - the tag

Returns:

True - if should be ignored, False otherwise

postfix

public Grammar postfix(Tag tag,
                       PostfixHandler handler)

Registers a PostfixHandler with a precedence of 1 for the given Tag

Parameters:

tag - the tag for which the handler will be registered

handler - the handler to associate with the given tag

Returns:

the grammar

postfix

public Grammar postfix(Tag tag,
                       PostfixHandler handler,
                       int precedence)

Registers a PostfixHandler with the given precedence for the given Tag

Parameters:

tag - the tag for which the handler will be registered

handler - the handler to associate with the given tag

precedence - the precedence of the tag (operator). Note that precedence will be the given value or 1 if the given value is less than 1.

Returns:

the grammar

postfix

public <E extends Expression> Grammar postfix(Tag tag,
                                              PostfixHandler handler,
                                              int precedence,
                                              SerializablePredicate<E> validator)

Registers a PostfixHandler with the given precedence for the given Tag

Type Parameters:

E - the type parameter

Parameters:

tag - the tag for which the handler will be registered

handler - the handler to associate with the given tag

precedence - the precedence of the tag (operator). Note that precedence will be the given value or 1 if the given value is less than 1.

validator - the validator to use validate the generated expression

Returns:

the grammar

precedenceOf

public int precedenceOf(Tag tag)

Determines the precedence of the given tag

Parameters:

tag - the tag

Returns:

the precedence

precedenceOf

public int precedenceOf(ParserToken token)

Determines the precedence of the Tag of the given ParserToken

Parameters:

token - the token for which the precedence will bec calculated.

Returns:

the precedence

prefix

public Grammar prefix(Tag tag,
                      PrefixHandler handler)

Registers a PrefixHandler for the given Tag

Parameters:

tag - the tag for which the handler will be registered

handler - the handler to associate with the given tag

Returns:

the grammar

prefix

public <E extends Expression> Grammar prefix(Tag tag,
                                             PrefixHandler handler,
                                             SerializablePredicate<E> validator)

Registers a PrefixHandler for the given Tag

Parameters:

tag - the tag for which the handler will be registered

handler - the handler to associate with the given tag

validator - the validator to use validate the generated expression

Returns:

the grammar

skip

public Grammar skip(Tag tag)

Registers the given Tag as one which should be skipped during parsing.

Parameters:

tag - the tag which will be skipped.

Returns:

the grammar

validatePostfix

public void validatePostfix(Expression expression)
                     throws ParseException

Validates the given expression as if it were generated from a postfix handler.

Parameters:

expression - the expression to validate

Throws:

ParseException - the exception if the expression is invalid

validatePrefix

public void validatePrefix(Expression expression)
                    throws ParseException

Validates the given expression as if it were generated from a prefix handler.

Parameters:

expression - the expression to validate

Throws:

ParseException - the exception if the expression is invalid