Package nz.org.riskscape.dsl

Class ConditionalParse<T>

java.lang.Object

nz.org.riskscape.dsl.ConditionalParse<T>

Type Parameters:

T - the type of thing returned by a parsing operation

public class ConditionalParse<T>
extends Object

Used to represent a parsing operation that's conditional on a sequence of token possibilities.

This type is used by Lexer.tryThese(ConditionalParse...) to help parses model a list of precedence ordered lookahead rules that give the basis of a grammar.

Constructor Summary

Constructors

Constructor	Description
ConditionalParse(String name, List<Set<? extends TokenType>> nextTokens, Supplier<T> parse)	Creates a new ConditionalParse instance.

Method Summary

Modifier and Type	Method	Description
protected boolean	canEqual(Object other)
boolean	equals(Object o)
String	getName()	Debugging name for this part of the grammar
List<Set<? extends TokenType>>	getNextTokens()	The sequence of tokens to be matched
Supplier<T>	getParse()	A callback that gives the results of parsing.
int	hashCode()
static <T> ConditionalParse<T>	parseIf(String name, List<Set<? extends TokenType>> nextTokens, Supplier<T> callback)	Construct a ConditionalParse that matches a sequence of possible tokens.
static <T> ConditionalParse<T>	parseIfIs(String name, List<? extends TokenType> nextTokens, Supplier<T> callback)	Convenience version of parseIf where the next sequence of tokens needs to match the sequence of token types in nextTokens
static <T> ConditionalParse<T>	parseIfIs(String name, TokenType nextToken, Supplier<T> callback)	Convenience version of parseIf where the next token has to be exactly the given token.
static <T> ConditionalParse<T>	parseIfOneOf(String name, Set<? extends TokenType> nextTokens, Supplier<T> callback)	Convenience version of parseIf(String, List, Supplier) with a singleton list.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

ConditionalParse

public ConditionalParse(String name,
 List<Set<? extends TokenType>> nextTokens,
 Supplier<T> parse)

Creates a new ConditionalParse instance.

Parameters:

name - Debugging name for this part of the grammar

nextTokens - The sequence of tokens to be matched

parse - A callback that gives the results of parsing.

Method Details

parseIf

public static <T> ConditionalParse<T> parseIf(String name,
 List<Set<? extends TokenType>> nextTokens,
 Supplier<T> callback)

Construct a ConditionalParse that matches a sequence of possible tokens.

Given the list of sets {S1, S2, S3}, then the returned ConditionalParse object would apply to a sequence of tokens where the next three tokens types are first in S1, second in S2 and then thirdly from S3. If this list was [{a, b}, {c}, {d, e}], then it would apply to [a, c, d], [b, c, d], [a, c, e] and [b, c, e].

Parameters:

name - debug identifier for the parsing step

nextTokens - the sequence of possible token types to match.

callback - a function to call that returns the results of parsing - it's assumed that the lexer is provided by the function's enclosing scope.

parseIfOneOf

public static <T> ConditionalParse<T> parseIfOneOf(String name,
 Set<? extends TokenType> nextTokens,
 Supplier<T> callback)

Convenience version of parseIf(String, List, Supplier) with a singleton list.

parseIfIs

public static <T> ConditionalParse<T> parseIfIs(String name,
 TokenType nextToken,
 Supplier<T> callback)

Convenience version of parseIf where the next token has to be exactly the given token.

parseIfIs

public static <T> ConditionalParse<T> parseIfIs(String name,
 List<? extends TokenType> nextTokens,
 Supplier<T> callback)

Convenience version of parseIf where the next sequence of tokens needs to match the sequence of token types in nextTokens

getName

public String getName()

Debugging name for this part of the grammar

getNextTokens

public List<Set<? extends TokenType>> getNextTokens()

The sequence of tokens to be matched

getParse

public Supplier<T> getParse()

A callback that gives the results of parsing.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

canEqual

protected boolean canEqual(Object other)

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object