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copied!<p>Here is one regular expression-based approach I have used in the past; it supports prefixes in combination with quoted strings.</p> <p>A more correct/robust/performant approach would involve writing a simple parser, however in most usage scenarios the time and effort associated with implementing and testing the parser would be vastly disproportionate to the gains.</p> <pre class="lang-cs prettyprint-override"><code>private static readonly Regex searchTermRegex = new Regex( @"^( \s* (?<term> ((?<prefix>[a-zA-Z][a-zA-Z0-9-_]*):)? (?<termString> (?<quotedTerm> (?<quote>['""]) ((\\\k<quote>)|((?!\k<quote>).))* \k<quote>? ) |(?<simpleTerm>[^\s]+) ) ) \s* )*$", RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture ); private static void FindTerms(string s) { Console.WriteLine("[" + s + "]"); Match match = searchTermRegex.Match(s); foreach(Capture term in match.Groups["term"].Captures) { Console.WriteLine("term: " + term.Value); Capture prefix = null; foreach(Capture prefixMatch in match.Groups["prefix"].Captures) if(prefixMatch.Index >= term.Index && prefixMatch.Index <= term.Index + term.Length) { prefix = prefixMatch; break; } if(null != prefix) Console.WriteLine("prefix: " + prefix.Value); Capture termString = null; foreach(Capture termStringMatch in match.Groups["termString"].Captures) if(termStringMatch.Index >= term.Index && termStringMatch.Index <= term.Index + term.Length) { termString = termStringMatch; break; } Console.WriteLine("termString: " + termString.Value); } Console.WriteLine(); } public static void Main (string[] args) { FindTerms(@"two terms"); FindTerms(@"prefix:value"); FindTerms(@"some:""quoted term"""); FindTerms(@"firstname:Jack ""the Ripper"""); FindTerms(@"'quoted term\'s escaped quotes'"); FindTerms(@"""unterminated quoted string"); } </code></pre> <p>Output:</p> <pre class="lang-none prettyprint-override"><code>[two terms] term: two termString: two term: terms termString: terms [prefix:value] term: prefix:value prefix: prefix termString: value [some:"quoted term"] term: some:"quoted term" prefix: some termString: "quoted term" [firstname:Jack "the Ripper"] term: firstname:Jack prefix: firstname termString: Jack term: "the Ripper" termString: "the Ripper" ['quoted term\'s escaped quotes'] term: 'quoted term\'s escaped quotes' termString: 'quoted term\'s escaped quotes' ["unterminated quoted string] term: "unterminated quoted string termString: "unterminated quoted string </code></pre>

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