Category Archives: XPath

Reason – Exciting New C++ Library For Internet Applications

I’ve been waiting for Emerson Clarke to GPL this library since he started sending me code samples via IM a few years ago. If you really want to squeeze every last nanoflop of performance out of your hardware then you need … Continue reading

Posted in C#, JavaScript, Massive, Web2.0, XML, XPath | 2 Comments

A Brief History Of Parsing

The primary goal a parser is to organize a sequence of tokens based on the rules of a formal language. As the parser accepts a sequence of tokens, it determines, based on this information, when the grammar’s respective rules are … Continue reading

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Adding XPath to Metawrap – Part I

As part of the MetaWrap Continuous Integration Project (mw_monitor), I have decided to add XPath to the MetaWrap XML engine. There are currently three methods I could use to process XML in mw_monitor. DTD Plug-in – Using this method I would … Continue reading

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Grammar Visualiser – Part II

http://documentation.metawrap.com/tests/dot/test3.png (generated automagically) http://documentation.metawrap.com/tests/dot/test.png (the original target plan) It lurches into being. I’m thinking that I may have to write this with MwW3ParserLexerState being the node instead of the current plan for MwW3ParserLexerStateGroup. The issue at hand is that a MwW3ParserLexerStateGroup can consist … Continue reading

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Grammar Visualiser – Part III

Its pretty obvious from this failed experiment that my original plan was the correct one. http://set-top.net/tests/dot/test7.png By associating an exact description of the potential state, but then using transitions wrt. the group of states, I’ve created something that makes logical sense … Continue reading

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More Parsing Terminology or "Teminator e"

A formal grammar is an abstract structure that describes a formal language precisely: i.e., a set of rules that mathematically delineates a (usually infinite) set of finite-length strings over a (usually finite) alphabet. A formal language is a set of finite-length character … Continue reading

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Merge At End Of A Lexical Sequence

The million dollar question is… Should a construction which consists of a simple option like “ABBB” | “CBBB” have a parse table that compresses and merges the last sequence of states into common groups? http://www.metawrap.com/tests/dot/test12.png In the same way that the start sequence … Continue reading

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Parsers Progress

http://www.metawrap.com/tests/dot/test9.png Minimal testcase for simplest production I could think of – with an at that un unhandled visitor type. (now implemented of course). The wonderful thing about applying such a complicated visitor pattern to this type of problem is that even though the first type … Continue reading

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Shared Infrustrature for W3 Specification Parsing – Part I

I have defined a new module for MetaWrap which consists of 4 Logical groups of classes. MwParser, MwParserBNF* and MwParserCST and MwParserAST. All the new W3 Specs seem to be heading towards shared definitions using BNF. (eh XQuery, XPath2.0 and XSLT2.0) . … Continue reading

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Some thoughts about parsing, protocols and XPath

Parsing And Protocols There are really two types of information packing in protocols and grammars and these boil down to data being length or lexically delimited. A parser implements a certain grammar. The grammar parses a certain pattern of tokens … Continue reading

Posted in Parsing Theory, XPath | 2 Comments