Content and license of *.rsc files

[wojteo]

What is the content and licensing of *.rsc files in org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser and in other directories ?

[srikanth-sankaran]

These are resource files that get generated by the jikespg parser generator used by Eclipse JDT to generate the Java language parser.
Unlike say javac from OpenJDK which uses a hand written parser to discover the syntactic structure of the input Java program and build a abstract syntax tree for it, Eclipse compiler for Java (ECJ) uses a parser generator which takes a grammar notation description file (see /org.eclipse.jdt.core.compiler.batch/grammar/java.g) and spits out a generated parser. This generated parser is a table driven LALR(1) parser and the state tables are contained in the rsc files (among other things needed by the DiagnoseParser - a syntax error correcting recovery parser)

The Java Language Specification is about a 1000 pages long but to parse the language the code involved is only 215 lines - with a lot of debug output code interleaved, See org.eclipse.jdt.internal.compiler.parser.Parser.parse()

In fact arguably the 34 line method org.eclipse.jdt.internal.compiler.parser.Parser.automatonWillShift(TerminalToken, int) embodies a full parser of the Java language!

Such a tightly coded parser is achieving by turning the parsing into a state transition question. The state table data form the resource files.

I hope this is useful 😆

As for licensing, I would think they are covered by the overall Eclipse SDK distribution license terms but I am no lawyer and if your situation calls for a more precise answer then you should persist with till you get an answer from an authority,

[iloveeclipse]

As for licensing, I would think they are covered by the overall Eclipse SDK distribution license terms but I am no lawyer and if your situation calls for a more precise answer then you should persist with till you get an answer from an authority,

I would assume org.eclipse.jdt.core.compiler.batch license covers everything we ship with the bundle and it would be EPL 2.0. Anything else would be a major surprise for me.

[wojteo]

Thank you for quick response :)