elm-matrix-sdk-beta/src/Internal/Tools/ParserExtra.elm

106 lines
2.5 KiB
Elm

module Internal.Tools.ParserExtra exposing (..)
import Parser as P exposing ((|.), (|=), Parser)
zeroOrMore : Parser a -> Parser (List a)
zeroOrMore parser =
P.loop []
(\tail ->
P.oneOf
[ P.succeed (\head -> P.Loop (head :: tail))
|= parser
, P.succeed (P.Done (List.reverse tail))
]
)
oneOrMore : Parser a -> Parser (List a)
oneOrMore parser =
P.succeed (::)
|= parser
|= zeroOrMore parser
atLeast : Int -> Parser a -> Parser (List a)
atLeast n parser =
P.loop []
(\tail ->
if List.length tail < n then
P.succeed (\head -> P.Loop (head :: tail))
|= parser
else
P.oneOf
[ P.succeed (\head -> P.Loop (head :: tail))
|= parser
, P.succeed (P.Done (List.reverse tail))
]
)
atMost : Int -> Parser a -> Parser (List a)
atMost n parser =
P.loop []
(\tail ->
if List.length tail < n then
P.oneOf
[ P.succeed (\head -> P.Loop (head :: tail))
|= parser
, P.succeed (P.Done (List.reverse tail))
]
else
P.succeed (P.Done (List.reverse tail))
)
times : Int -> Int -> Parser a -> Parser (List a)
times inf sup parser =
let
low : Int
low =
max 0 (min inf sup)
high : Int
high =
max 0 sup
in
P.loop []
(\tail ->
if List.length tail < low then
P.succeed (\head -> P.Loop (head :: tail))
|= parser
else if List.length tail < high then
P.oneOf
[ P.succeed (\head -> P.Loop (head :: tail))
|= parser
, P.succeed (P.Done (List.reverse tail))
]
else
P.succeed (P.Done (List.reverse tail))
)
exactly : Int -> Parser a -> Parser (List a)
exactly n =
times n n
maxLength : Int -> Parser a -> Parser a
maxLength n parser =
P.succeed
(\start value end ->
if abs (end - start) > n then
P.problem "Parsed too much text!"
else
P.succeed value
)
|= P.getOffset
|= parser
|= P.getOffset
|> P.andThen identity