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POHaskell Parsec and Unordered Properties
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  1. POHaskell Parsec and Unordered Properties
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    copied!<p>I am trying to use Parsec to parse something like this:</p> <pre><code>property :: CharParser SomeObject property = do name parameters value return SomeObjectInstance { fill in records here } </code></pre> <p>I am implementing the iCalendar spec and on every like there is a name:parameters:value triplet, very much like the way that XML has a name:attributes:content triplet. Infact <a href="http://tools.ietf.org/html/draft-daboo-et-al-icalendar-in-xml-06" rel="noreferrer">you could very easily convert an iCalendar into XML format</a> (thought I can't really see the advantages).</p> <p>My point is that the parameters do not have to come in any order at all and each paramater may have a different type. One parameter may be a string while the other is the numeric id of another element. They may share no similarity yet, in the end, I want to place them correctly in the right record fields for whatever 'SomeObjectInstance' that I wanted the parser to return. How do I go about doing this sort of thing (or can you point me to an example of where somebody had to parse data like this)? </p> <p>Thankyou, I know that my question is probably a little confused but that reflects my level of understanding of what I need to do.</p> <p><strong>Edit</strong>: I was trying to avoid giving the expected output (because it is large, not because it is hidden) but here is an example of an input file (from wikipedia):</p> <blockquote> <p>BEGIN:VCALENDAR<br> VERSION:2.0<br> PRODID:-//hacksw/handcal//NONSGML v1.0//EN<br> BEGIN:VEVENT<br> UID:uid1@example.com<br> DTSTAMP:19970714T170000Z<br> ORGANIZER;CN=John Doe:MAILTO:john.doe@example.com<br> DTSTART:19970714T170000Z<br> DTEND:19970715T035959Z<br> SUMMARY:Bastille Day Party<br> END:VEVENT<br> END:VCALENDAR </p> </blockquote> <p>As you can see it contains one VEvent inside a VCalendar, I have made <a href="http://github.com/robertmassaioli/hICalendar/blob/combined/Text/ICalendar/Components.hs" rel="noreferrer">data structures that represent them here</a>.</p> <p>I am trying to write a parser that parses that type of file into my data structures and I am stuck on the bit where I need to handle properties coming in any order with any type; date, time, int, string, uid, ect. I hope that makes more sense without repeating the entire iCalendar spec.</p>
 

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