groovy-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jesper Steen Møller <>
Subject Progress on the Antlr4-based parser
Date Mon, 07 Mar 2016 06:48:04 GMT
Hi again Groovy-Dev

Here’s another update on the progress on the Antlr4 parser. I’m still exploring the limitations
of the parser, partly by inspection and comparison with the Groovy documentation, and partly
by experimentation (letting it loose on all the *.groovy files in the repository)

Since last update, I’ve fixed a number of issues:
assert statement (with either colon or comma as separator)
Added cast operator
super() or this()-call in constructors
Support identifiers as property names and map literal entry names
Incorporated Pavel’s ASTBuilder as Java. And un-machinetranslated in where I could, so it’s
more idiomatic Java-ish.
Multiple declarations are now handled in locals and fields/properties.
Trailing commas are OK in lists and maps
Scripts may contain methods now
Updated Antlr4 version and made it configurable with the others in main build.gradle
Fixed the classname-detection login (Now I will never, ever forget binarySearch’s return
Allow F and D as suffix to integer literals
Allow static import and imports with aliases
Still outstanding:
Full Unicode letter support  for identifiers
Proper unescaping of string literals
The grammar is too limited around call expressions trailing a non-path expression
Some combinations of parameterless calls and closure-only calls don’t work yet
Error messages look a lot different from the old parser - may need some qork
Haven’t looked at error recovery -(single token correction built into Antlr4 does some of
the work)
Some newline handling around various operators need attention
So you can help me with a couple of answers:
Is it a goal to close the gap to Java’s more trickier syntax, such as placement-new and
placement constructor calls? From what I can tell, we’d have to extend the AST too to support
that. Has anyone ever used that except in compiler test cases?
./benchmark/bench/heapsort.groovy uses access modfiers on the script’s local variables —
that’s not really allowed, is it? How should that work? It can’t get it to work in Groovy

As before, to play with it, try:

$ git clone -b antlr4 <>
$ cd groovy
$ gradle -PuseAntlr4=true console

Have fun.

View raw message