In ANTLR 3, how do I generate a lexer (and parser) at runtime instead of ahead of time?

Question

I want to generate an antlr lexer at runtime -- that is, generate the grammar and from the grammar generate the lexer class, and its supporting bits at runtime. I am happy to fe

Answer 1

You'll have to use org.antlr.Tool() class to get it working.

You can check ANTLRWorks source code on github to have an idea how to use it, specifically the generate() method here:

ErrorListener el = ErrorListener.getThreadInstance();
ErrorManager.setErrorListener(el);

String[] params;
if(debug)
    params = new String[] { "-debug", "-o", getOutputPath(), "-lib", window.getFileFolder(), window.getFilePath() };
else
    params = new String[] { "-o", getOutputPath(), "-lib", window.getFileFolder(), window.getFilePath() };

new File(getOutputPath()).mkdirs();

Tool antlr = new Tool(Utils.concat(params, AWPrefs.getANTLR3Options()));
antlr.process();

boolean success = !el.hasErrors();
if(success) {
    dateOfModificationOnDisk = window.getDocument().getDateOfModificationOnDisk();
}
lastError = el.getFirstErrorMessage();
el.clear();
ErrorManager.removeErrorListener();
return success;