Parsing methods

Pelvis

I'm reading through a code base and it has a parsing class with many various boolean methods like so...

final private boolean jj_2_10(int xla) {
		jj_la = xla;
		jj_lastpos = jj_scanpos = token;
		try {
			return !jj_3_10();
		} catch (LookaheadSuccess ls) {
			return true;
		} finally {
			jj_save(9, xla);
		}
	}

	final private boolean jj_3_7() {
		if (jj_scan_token(PARAMSTART))
			return true;
		if (jj_scan_token(WORD))
			return true;
		return false;
	}

	final private boolean jj_3_5() {
		if (jj_scan_token(WORD))
			return true;
		return false;
	}

	final private boolean jj_3_4() {
		if (jj_scan_token(WORD))
			return true;
		Token xsp;
		if (jj_3_3())
			return true;
		while (true) {
			xsp = jj_scanpos;
			if (jj_3_3()) {
				jj_scanpos = xsp;
				break;
			}
		}
		return false;
	}

	final private boolean jj_3_6() {
		if (jj_scan_token(PARAMSTART))
			return true;
		if (jj_scan_token(WORD))
			return true;
		if (jj_scan_token(WORD))
			return true;
		return false;
	}

Can anyone give me an idea what's happening here? The method names appear to have some meaning but google doesn't really help me figure out what.

14ned

Pelvis wrote: »

Can anyone give me an idea what's happening here? The method names appear to have some meaning but google doesn't really help me figure out what.

It looks to be output from a compiler compiler such as yacc, "yet another compiler compiler"

(or whatever equivalent php uses)

Niall

Talisman

The "jj_" prefixes are a dead giveaway that it's code that was originally generated for a Java project. The parser was originally created using the Java Compiler Compiler toolkit, JavaCC.

It's been a while since I've seen the code but I think you may have an attempted port to PHP of the query parser from the Apache Solr project.

Pelvis

Sorry guys, it is actually a java project! Used the wrong tags in my post, oops!

Talisman

Check for a .jj file in the project, it will contain the parsing information. The javacc tool transforms the contents of a .jj grammar file into the Java code for the parser classes.

Description of the JavaCC Grammar File

Pelvis

That's great, thanks. Now I don't feel so bad for not having a clue what's going on in the auto generated files.