Command string parser

gistfile1.fs

// Takes a "quoted argument string ignoring \" escaped" arguments. Returns an array of arguments

let commandStringToArguments (cmd: string) =
    // Checks whether a quote is lead by an escape char
    let isUnescapedQuote (i, c) =
        c.Equals('"') && (i.Equals(0) || (cmd |> Seq.toArray).[i-1] <> '\\')
    // Get the start and end position of quoted strings
    let quotedStrings =
        cmd
         |> Seq.toArray
         |> Array.mapi (fun i c -> (i, c))
         |> Array.filter (fun point -> isUnescapedQuote point)
         |> Array.map (fun (i, c) -> i)
         |> Seq.pairwise
         |> Seq.toArray
         |> Array.map (fun (s, e) -> (s+1, e-1))
    // Checks if current position is inside a quoted string
    let outsideQuotedString i =
        let count =
            quotedStrings
             |> Array.filter (fun (sstart, send) -> i >= sstart && i <= send)
             |> Array.length
        count.Equals(0)
    // Locate all unquoted words
    let words =
        cmd
         |> Seq.toArray
         |> Array.mapi (fun i c -> (i+1, c))
         |> Array.filter (fun (i, c) -> c.Equals(' '))
         |> Array.map (fun (i, c) -> i)
         |> Array.filter (fun i -> outsideQuotedString i)
         |> Array.append [|0|]
    // Get start positions for all commands in command string
    let startPositions =
        words
         |> Array.append (quotedStrings |> Array.map (fun (start, _) -> start))
         |> Array.sort
         |> Seq.distinct
         |> Seq.toArray
    // Parse out a list of commands from start and end position
    startPositions
     |> Array.mapi (fun i p ->
        if i.Equals((startPositions |> Array.length)-1) then (p, cmd.Length)
        else (p, startPositions.[i+1]-1))
     |> Array.map (fun (s, e) -> cmd.Substring(s, e-s))