public void write(ST code, String fileName) {
		try {
//			long start = System.currentTimeMillis();
			Writer w = tool.getOutputFileWriter(g, fileName);
			STWriter wr = new AutoIndentWriter(w);
			wr.setLineWidth(lineWidth);
			code.write(wr);
			w.close();
//			long stop = System.currentTimeMillis();
		}
		catch (IOException ioe) {
			tool.errMgr.toolError(ErrorType.CANNOT_WRITE_FILE,
								  ioe,
								  fileName);
		}
	}
Generate a token vocab file with all the token names/types.  For example:
 ID=7
 FOR=8
 'for'=8

 This is independent of the target language; used by antlr internally
tool/src/org/antlr/v4/codegen/CodeGenerator.java