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POPreg Patterns, to ignore escaped characters
 

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    <p>I want to create a RegEx that finds strings that begin and end in single or double quotes.</p> <p>For example I can match such a case like this:</p> <pre><code>String: "Hello World" RegEx: /[\"\'][^\"\']+[\"\']/ </code></pre> <p>However, the problem occurs when quotes appear in the string itself like so:</p> <pre><code>String: "Hello" World" </code></pre> <p>We know the above expression will not work.</p> <p>What I want to be able to do, it to have the escape within the string itself, since that will be functionality required anyway:</p> <pre><code>String: "Hello\" World" </code></pre> <p>Now I could come up with a long and complicated expression with various patterns in a group, one of them being:</p> <pre><code>RegEx: /[\"\'][^\"\']+(\\\"|\\\')+[^\"\']+[\"\']/ </code></pre> <p>However that to me seems excessive, and I think there may be a shorter and more elegant solution.</p> <p>Intended syntax:</p> <pre><code>run arg1 "arg1" "arg3 with \"" "\"arg4" "arg\"\"5" </code></pre> <p>As you can see, the quotes are really only used to make sure that string with spaces are counted as a single string. Do not worry about <code>arg1</code>, I should be able to match unquoted arguments.</p> <p><strong>I will make this easier, arguments can only be quoted using double-quotes. So i've taken single quotes out of the requirements of this question.</strong></p> <p>I have modified Rui Jarimba's example:</p> <pre><code>/(?&lt;=")(\\")*([^"]+((\\(\"))*[^"])+)((\\"")|")/ </code></pre> <p>This now accounts pretty well for most cases, however there is one final case that can defeat this:</p> <pre><code>run -a "arg3 \" p2" "\"sa\"mple\"\\" </code></pre> <p>The second argument end with <code>\\"</code> which is a conventional way in this case to allow a backslash at the end of a nested string, unfortunately the regex thinks this is an escaped quote since the pattern <code>\"</code> still exists at the end of the pattern.</p>
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    1. COOn what basis is the script supposed to know what quotes to change and witch ones to count as start/end parameters?
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    2. CODepending on the outer quotes, yes, a larger string could contain more that one quoted nested string, so the reg ex would have to be able to find them all. If a nested string is encapsulated with single quotes, then any inside double quotes need not be escaped, and visa versa.
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    3. COSo you are looking for all text between the `first` and `last` quotes?
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