Parse using a list of strings in FParsec

Question

I am checking for reserved words using something like this:

let astr s = attempt (pstringCI s)
let reservedWord = astr "text" <|> astr "date" // etc.

Is it possible to create a parser performs the same check but which takes an array of the reserved words as a parameter? Something like:

newReservedWordParser "something" ["text"; "date"; ...]

score 2 · Accepted Answer · answered Dec 24 '19 at 16:22

2

Why not use choice? It takes a seq as parameter.

You can use it like so:

let reservedWords = [
    "word1"
    "word2"
]

let parseReservedWord = reservedWords |> List.map pstringCI |> choice

I'm doing something similar in my project here

answered Dec 24 '19 at 16:22

Tyrrrz

2,492
1
19
29

1

Oh, wow - how simple is that? You can just pipe it to choice!!! Thank you, @Tyrrz :) – Sean Kearon Dec 26 '19 at 09:33

Sean Kearon · Answer 2 · 2019-11-15T15:37:15.143

0

Having stumbled across the answer from @bytebuster here, this can be done like so (not sure I need this any longer though!):

let reservedWord (reservedWords: string list) = 
    (many1 letter |>> System.String.Concat) >>= 
    fun x -> 
        if List.contains x reservedWords then preturn x 
        else fail "not a reserved word"

LINQPad share here.

FParsec documentation about >>= is here.

edited Nov 15 '19 at 15:37

answered Nov 15 '19 at 15:08

Sean Kearon

10,987
13
77
93

Parse using a list of strings in FParsec

2 Answers2