Disclaimer: Work is either in progress or abandoned. Proceed only if you are really curious.
The fully working version, where all tests pass, lies under the tag before-docs-and-refactorings, but the Parser.elm is just one huge file there.
Current version is a work on splitting the API into proper modules and some unfinished docs.
The (Execute.elm)[./blob/master/src/Execute.elm] file could be interesting for someone, since it's the implementation of all possible parser operators on functions :).
However, I see there are a lot of awesome parsers and parser-generators do exist for Elm already. This project really helped me in discovering Elm hidden tricks, so I may use them for other things (and also it teached me to use elm-format :) ) and, probably, just move on.
The idea was to tranfer the idea of pegjs-fn, "functional" parser generator to Elm, so the parser grammar could look like this:
type alias ReturnType = String
rules : Rules ReturnType
rules =
[ ( "phoneNumber"
, action
( seqnc
[ maybe (call "prefix")
, maybe (call "operator")
, (call "local")
]
)
(\val _ -> extractPhoneNumber val)
)
, ( "prefix"
, action
( seqnc
[ match "+"
, some (re "[0-9]")
]
)
(\val _ -> extractPrefix val)
)
, ( "operator"
, action
( seqnc
[ choice [ match "(", match "[" ]
, some (re "[0-9]")
, choice [ match "]", match ")" ]
]
)
(\val _ -> extractOperator val)
)
, ( "local"
, action
( seqnc
[ some (re "[0-9]")
, match "-"
, some (re "[0-9]")
, match "-"
, some (re "[0-9]")
]
)
(\val _ -> extractLocal val)
)
]
init : Parser ReturnType
init =
Parser.withRules rules
|> Parser.setStartRule "phoneNumber"
test : ParseResult ReturnType
test =
init |> Parser.parse "35[057]776-22-13"This way to define parser also allows user to export them to PEG format easily.
See samples (or samples from previous version) for more examples.
Thanks Elm for its beauty and recursive data structures.