How to create a scripting language in java?

Question

Hello,
All that I want to do is to create a scripting language in java. I�m familiar with javacc, jsr223 and other things but don�t know how to start. The language syntax is java 5 syntax with some change and I want to generate java source code from small scripts. In fact I don�t know how other languages (like groovy) are created.
I hope you can show me the required steps.
Looking forward to hear from you.
Thanks.

Answer 1

That's all, huh?
For a start, generally when I hear "scripting language" I'm thinking interpretter, not a system which creates compiled (or compilable) code.
I get the impression that what you're talking about is what I'd call a "preprocessor" language, some extra syntax added to java which the preprocessor renders into ordinary java.
As far as complexity is concerned, much depends on how deeply involved the extra syntax is with the embedded ordinary Java. Does you preprocessor need to understand the java, or is it just embedded as text? How easilly identified are your preprocesor statments? It's a lot easier to do this if preprocessor lines are instantly identifiable from Java code (e.g. start with a #).
Basically the stages are always the same;
1) Lexical analysis i.e. picking out words, operators, numbers, quoted strings.
2) Construct a syntax tree.
3) Generate code (in this case Java).
Now, in this case, some of the nodes in the syntax tree may simply be chunks of undigested Java.