81 lines
2.3 KiB
C#
81 lines
2.3 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Text.RegularExpressions;
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namespace BotSharp.NLP.Tokenize
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{
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public class RegexTokenizer : ITokenizer
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{
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public SupportedLanguage Lang { get; set; }
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/// <summary>
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/// Tokenize a text into a sequence of alphabetic and non-alphabetic characters
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/// </summary>
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public const string WORD_PUNC = @"\w+|[^\w\s]+";
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/// <summary>
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/// Tokenize a string, treating any sequence of blank lines as a delimiter.
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/// Blank lines are defined as lines containing no characters, except for space or tab characters.
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/// options.IsGap = true
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/// </summary>
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public const string BLANK_LINE = @"\s*\n\s*\n\s*";
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/// <summary>
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/// Tokenize a string on whitespace (space, tab, newline).
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/// In general, users should use the string ``split()`` method instead.
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/// options.IsGap = true
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/// </summary>
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public const string WHITE_SPACE = @"\s+";
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private Regex _regex;
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public Token[] Tokenize(string text, TokenizationOptions options)
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{
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_regex = new Regex(options.Pattern);
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var matches = _regex.Matches(text).Cast<Match>().ToArray();
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options.IsGap = new string[] { WHITE_SPACE, BLANK_LINE }.Contains(options.Pattern);
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if (options.IsGap)
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{
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int pos = 0;
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int span = 0;
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var tokens = matches.Select(x =>
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{
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var token = new Token
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{
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Text = (span == matches.Length - 1) ? text.Substring(pos) : text.Substring(pos, x.Index - pos),
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Offset = pos
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};
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pos = x.Index + 1;
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if (span == matches.Length - 1)
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{
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}
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span++;
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return token;
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}).ToArray();
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return tokens;
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}
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else
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{
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return matches.Select(x => new Token
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{
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Text = x.Value,
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Offset = x.Index
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}).ToArray();
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}
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}
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}
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}
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