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Add a wrapper around AST that exposes fields #9
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…orm some basic house keeping
…und with computed fields
…existing grammar and then to automatically generate fields for that
…ssociating which fields to skip for which rules
…ctor to make room for remaining fields yet to be implemented
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The process for exposing the data that's parsed is a little strange and convoluted. There's an additional "rewriting" step, where the original rfc5322 grammar is rewritten with the help of a metagrammar, and variable names A-Z are assigned to each atom, before being saved. In the same file that coordinates the rewriting, there's the opportunity to rewrite some of those automatically assigned field names to ones that are more easily read.
After this, the resulting rewritten grammar can then be used to generate a new parser, while the original rfc5322 grammar remains untouched.
The reason for doing this is the grammar is too big to easily add computed fields without at the same time making it illegible and basically turning the grammar into a program. It's very important for the original grammar to easily be understandable, but also for there to be an easy way for changes made to it to automatically cause changes downstream.
As a final thought, there are at least big remaining issues left in the project: