Hi Claus,
the parser looks quite good as far as I looked into it. In any case much
better than regex. Before we replace the old parser we should also think
about tooling though. Some longer time ago I thought about using Xtext
for the camel DSL and also the languages. The advantage would be that it
is quite easy to build real good Editor for the IDE. I guess with the
aproach you followed this is not so easy. Of ocurse the initial effort
of Xtext would be a lot higher but perhaps it can pay off in the long run.
Christian
Am 29.08.2011 10:18, schrieb Claus Ibsen:
Hi
The current Simple language in camel-core has reached its potential in
terms of maintenance and how easy it would be, for example to add new
functions and operators. Likewise the current error reporting is not
precise to point out where in the expression String the problem is.
The implementation is using regular expressions, and that is one of
the key problems. I think we have grown to the limit how it is to
maintain.
So I have experimented this weekend to build a prototype based on the
principle of a recursive descent parser
http://en.wikipedia.org/wiki/Recursive_descent_parser
I at first looked into using a parser framework such as JavaCC and
ANTLR. The former would be able to parse the input, but building the
AST nodes would require to use its tree compiler, which was not maven
exposed. Likewise JavaCC is not really maintained anymore. People on
stackoverflow recommended ANTLR. It has more bells ans whistles, but
as far as I could see ANTLR requires JAR files in the runtime.
And frankly I just wanted a fairly simple code, that anybody, would be
able to look into and help with.
So I cracked up some prototype code based on the principle from that
wikipedia article above.
--
--
Christian Schneider
http://www.liquid-reality.de
Open Source Architect
Talend Application Integration Division http://www.talend.com
