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The top-level rule in the SableCC grammar is
grammar = P.package? P.Helpers? P.states? P.tokens? ign_tokens?
But it's convenient for a grammar writer to have a stock template,
especially because the order of these sections is fixed.
/* Stock header for my template */
Ignored Tokens ;
In the current grammar for SableCC, the above is invalid. In fact, any
time any of those sections is empty, you're not allowed to use the
keyword for that section.
A few small changes to the grammar would allow empty sections without
invalidating the grammar or having to comment out a section.
helper_def = helper? semicolon;
helper = id equal reg_exp;
token_def = token? semicolon;
token = state_list? id equal reg_exp look_ahead?;
prod = production? semicolon;
production = id equal alts;
The ramification of this is that extra semicolons can be used without
getting syntax errors, at the cost of recognizing (and ignoring) empty
Steven Kelem, Ph.D.