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Parser Parsetransform

This parse transform makes it write simple parsers.

Simply define functions of the form:

Fun(Args1,Input,Args2) -> parser:binary(Input);
Fun(Args1,<<Before,Pat1,After>>,Args2) -> do_stuff;
...
Fun(Args1,<<Before,PatN,After>>,Args2) -> do_stuff;
Fun(Args1,NoMatch,Args2) -> do_other_stuff;

where Pat1..PatN are Strings or lists of strings wich must be matched exactly, the be rewritten to pattern match on the input in a manar similar to binary:match/2.

If no clause matches {error,eof} is returned, particularly if no final default clause matches.

Notes

  • The generated code is reasonably fast, at the expense of code size (particularly do_stuff may be duplicated)

  • Currently matching only works on binaries, but the plan is to support matching on lists and iolists.

  • Matching has been somewhat optimized using tries, specifically if multiple patterns share a common prefix this is matched out first and then dispatched to the appropriate clause.

  • Several internal functions are generated of the form Fun#something.

Todos

  • Reduce code duplication.
  • Support matching on iolists and lists.