Introduction - brief overview, history
 - code organization


Example rule (with pointers to explanations)

Front-End
 - Server mode
 - Interactive mode
 - Batch mode
 - Debugging/tracing

Back-end
 - Operators
 - get-lex(-fs)
 - equations/equation blocks
 - grammar rules
 - grammar/lexicon loading and side effects
 - Humble suggestions for grammar writers
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