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POMost efficient algorithm for parsing nested blocks with escapes or delimiters
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  1. POMost efficient algorithm for parsing nested blocks with escapes or delimiters
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    copied!<p>I define a nested block as something with separate opening and closing characters. I.e. <code>{</code> and <code>}</code>, <code>[</code> and <code>]</code>, etc. An algorithm must ignore opening and closing characters if they are enclosed in a delimiter (such as <code>'{'</code> or <code>"{"</code>), or explicitly escaped such as in a comment block. </p> <p>This is not homework (I'm not a student) or idle speculation. My immediate goal is to alphabetically reorder function declarations in ActionScript code files to assist in debugging / comparing different versions. But the real question and more useful for other readers is the general algorithm as described above. In my case the plug-in parameters are just opening = <code>{</code>, closing = <code>}</code>, delimiter = <code>"</code>, escape = <code>//..[end of line]</code>.</p> <p>Please see the following for existing questions that explain why <strong>regular expressions are not an option</strong> for parsing arbitrarily deep nested expressions:</p> <ul> <li><a href="https://stackoverflow.com/questions/133601/can-regular-expressions-be-used-to-match-nested-patterns">Can regular expressions be used to match nested patterns?</a></li> <li><a href="https://stackoverflow.com/questions/7151468/how-can-i-parse-nested-blocks-using-regex">How can I parse nested blocks using Regex? [closed]</a></li> </ul> <p>The obvious blunt solution is to chug through character-by-character and build a context stack and state variables ("inQuote", "inComment", etc). I've done this before. I'm just wondering if there is a more formal or efficient solution; or if this is irreducable. </p>
 

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