viktorklang

/*
Copyright 2012-2021 Viktor Klang
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
 
       http://www.apache.org/licenses/LICENSE-2.0
 
   Unless required by applicable law or agreed to in writing, software

pathikrit

class NorvigSpellChecker(corpus: String, alphabet: Seq[Char] = 'a' to 'z', level: Int = 2) {
  val words = s"[${alphabet.head}-${alphabet.last}]+".r.findAllIn(corpus.toLowerCase).toSeq

  val count = words.groupBy(_.toSeq).mapValues(_.size) withDefaultValue 0

  def edit(n: Int)(word: Seq[Char]): Set[Seq[Char]] = n match {
    case 0 => Set(word)
    case 1 =>
      val splits = word.indices map word.splitAt
      val deletes = splits collect {case (a, b0 +: b1) => a ++ b1}