[F#] Novial dictionary converter

Convert.fsx

// https://sites.google.com/site/noviallexike/novial-lexike-1930

// https://gist.github.com/7shi/de072cd867f3899aa285bc9343110bff
#load "XmlParser.fsx"

open System.IO
open XmlParser

do
use xp = new XmlParser(new StreamReader("novial.html"))
use sw = new StreamWriter("novial.txt")
let mutable prev = ""
for p in xp.SearchEach("p") do
    let mutable s = ""
    while xp.Read() && xp.Tag <> "/p" do
        if s.Length > 0 then s <- s + " "
        s <- s + xp.Text.Replace("\n", " ")
    while s.IndexOf "  " >= 0 do
        s <- s.Replace("  ", " ")
    s <- s.Replace(" \xA0 ", "  ").Replace("  |", " |").Trim()
    if s = "A" then
        prev <- s
    elif prev.Length > 0 then
        sw.Write(prev)
        if s.StartsWith("Pronuntiatione:") then
            sw.Write(" | ")
        else
            sw.WriteLine()
        prev <- s