org.jparsercombinator.ParserCombinators Maven / Gradle / Ivy
package org.jparsercombinator;
import java.util.regex.MatchResult;
import java.util.regex.Pattern;
/**
* Factory methods for creating common parser combinators.
*/
public final class ParserCombinators {
private ParserCombinators() {
}
/**
* Creates a {@code ParserCombinator} that accepts given string only.
*
* @param str string accepted by the parser
* @return the string that was accepted
*/
public static ParserCombinator string(String str) {
return regex(Pattern.quote(str));
}
/**
* Creates a {@code ParserCombinator} that accepts inputs matching given regex.
*
* @param regex pattern accepted by the parser
* @return the matching input as a whole
*/
public static ParserCombinator regex(String regex) {
return regexMatchResult(regex).map(MatchResult::group);
}
/**
* Creates a {@code ParserCombinator} that accepts inputs matching given regex.
*
* @param regex pattern accepted by the parser
* @return the regex match result for further grouping etc.
*/
public static ParserCombinator regexMatchResult(String regex) {
return new RegexParserCombinator(Pattern.compile(regex));
}
/**
* Creates a {@code SkipCombinator} for building a {@code ParserCombinator} that skips first then
* applies next combinator. For example {@code skip(string("(")).next(string("foo")).skip(string(")"))}
* parses parenthesized string "foo".
*
* @param skip a parser to be skipped
* @return {@code SkipCombinator} that provides {@code next(ParserCombinator next)} for
* building a new {@code ParserCombinator} that skips the first combinator then applies next.
*/
public static SkipCombinator skip(ParserCombinator skip) {
return new SkipCombinator(skip);
}
/**
* Creates a {@code ParserCombinatorReference} that can be used to create self referencing
* recursive parsers. {@code ParserCombinatorReference} is simply a minimal implementation of the
* delegate pattern.
*
* @param type of the parse result
* @return a new {@code ParserCombinatorReference}
*/
public static ParserCombinatorReference newRef() {
return new ParserCombinatorReference<>();
}
}