Advice on FParsec for handling whitespace

f#, fparsec

Solution

let s1 = "5.75         @             5.95              "
let s2 = "5.75/5.95   "
let pquote: Parser<_> =
    pfloat
    .>> spaces .>> skipAnyOf ['@'; '/'] .>> spaces
    .>>. pfloat
    .>> spaces

Notes:

- I've made `spaces` optional everywhere `spaces` skips any sequence of zero or more whitespaces, so there's no need to use `opt` - thanks @Daniel;

- `type Parser<'t> = Parser<'t, UserState>` - I define it this way in order to avoid "value restriction" error; you may remove it;

- Also, don't forget the following if your program may run on a system with default language settings having decimal comma: `System.Threading.Thread.CurrentThread.CurrentCulture <- Globalization.CultureInfo.GetCultureInfo "en-US"` this won't work, thanks @Stephan

- I would not use `sepBy` unless I have a value list of unknown size.

- If you don't really need the value returned (e.g. `'@'` characters), it is recommended to use `skip*` functions instead `p*` for performance considerations.

UPD added slash as separator

Problem

I have the following subexpression to parse 'quotes' which have the following format ``` "5.75 @ 5.95" ``` I therefore have this parsec expression to parse it ``` let pquote x = (sepBy (pfloat) ((spaces .>> (pchar '/' <|> pchar '@' )>>. spaces))) x ``` It works fine.. except when there is a trailing space in my input, as the separator expression starts to consume content.So I wrapped it around an attempt, which works and seems, from what I understand, more or less what this was meant to be. ``` let pquote x = (sepBy (pfloat) (attempt (spaces .>> (pchar '/' <|> pchar '@' )>>. spaces))) x ``` As I dont know fparsec so well, I wonder if there are any better way to write this. it seems a bit heavy (while still being very manageable of course)

Original source