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POHow to create a parser(lex/yacc)?
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  1. POHow to create a parser(lex/yacc)?
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    copied!<p>I'm having the following file and which need to be parsed</p> <pre><code>--TestFile Start ASDF123 Name "John" Address "#6,US" end ASDF123 </code></pre> <p>The lines start with <code>--</code> will be treated as comment lines. and the file starts 'Start' and ends with <code>end</code>. The string after <code>Start</code> is the <code>UserID</code> and then the <code>name</code> and <code>address</code> will be inside the double quots.</p> <p>I need to parse the file and write the parsed data into an xml file.</p> <p>So the resulting file will be like</p> <pre><code>&lt;ASDF123&gt; &lt;Name Value="John" /&gt; &lt;Address Value="#6,US" /&gt; &lt;/ASDF123&gt; </code></pre> <p>now i'm using pattern matching(<code>Regular Expressions</code>) to parse the above file . Here is my sample code.</p> <pre><code> /// &lt;summary&gt; /// To Store the row data from the file /// &lt;/summary&gt; List&lt;String&gt; MyList = new List&lt;String&gt;(); String strName = ""; String strAddress = ""; String strInfo = ""; </code></pre> <p><strong>Method</strong> : ReadFile</p> <pre><code> /// &lt;summary&gt; /// To read the file into a List /// &lt;/summary&gt; private void ReadFile() { StreamReader Reader = new StreamReader(Application.StartupPath + "\\TestFile.txt"); while (!Reader.EndOfStream) { MyList.Add(Reader.ReadLine()); } Reader.Close(); } </code></pre> <p><strong>Method</strong> : FormateRowData</p> <pre><code> /// &lt;summary&gt; /// To remove comments /// &lt;/summary&gt; private void FormateRowData() { MyList = MyList.Where(X =&gt; X != "").Where(X =&gt; X.StartsWith("--")==false ).ToList(); } </code></pre> <p><strong>Method</strong> : ParseData</p> <pre><code> /// &lt;summary&gt; /// To Parse the data from the List /// &lt;/summary&gt; private void ParseData() { Match l_mMatch; Regex RegData = new Regex("start[ \t\r\n]*(?&lt;Data&gt;[a-z0-9]*)", RegexOptions.IgnoreCase); Regex RegName = new Regex("name [ \t\r\n]*\"(?&lt;Name&gt;[a-z]*)\"", RegexOptions.IgnoreCase); Regex RegAddress = new Regex("address [ \t\r\n]*\"(?&lt;Address&gt;[a-z0-9 #,]*)\"", RegexOptions.IgnoreCase); for (int Index = 0; Index &lt; MyList.Count; Index++) { l_mMatch = RegData.Match(MyList[Index]); if (l_mMatch.Success) strInfo = l_mMatch.Groups["Data"].Value; l_mMatch = RegName.Match(MyList[Index]); if (l_mMatch.Success) strName = l_mMatch.Groups["Name"].Value; l_mMatch = RegAddress.Match(MyList[Index]); if (l_mMatch.Success) strAddress = l_mMatch.Groups["Address"].Value; } } </code></pre> <p><strong>Method</strong> : WriteFile</p> <pre><code> /// &lt;summary&gt; /// To write parsed information into file. /// &lt;/summary&gt; private void WriteFile() { XDocument XD = new XDocument( new XElement(strInfo, new XElement("Name", new XAttribute("Value", strName)), new XElement("Address", new XAttribute("Value", strAddress)))); XD.Save(Application.StartupPath + "\\File.xml"); } </code></pre> <p>i've heard of <a href="http://www.bumblebeesoftware.com/" rel="nofollow">ParserGenerator</a></p> <p>Please help me to write a parser using lex and yacc. The reason for this is , my exsisting parser(<code>Pattern Matching</code>) is not flexible, more over its not the right way(I think so).</p> <p>How to i make use of the <code>ParserGenerator</code>(I've read <a href="http://www.codeproject.com/KB/recipes/introlexyacc.aspx" rel="nofollow">Code Project Sample One</a> and <a href="http://www.codeproject.com/KB/recipes/lexyacc2.aspx?msg=2067628" rel="nofollow">Code Project Sample Two</a> but still i'm not familiar with this). Please suggest me some parser generator which outputs C# parsers.</p>
 

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