[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Type and Structure Re: ASN.1 and XML
Sorta. Even more ancient works of lore have some notions of the sepration of syntax and semantic if only as separate stacks. "In any PL implementation, that are actually at least two stacks which work in parallel. One, the syntax stack SYN.. The second, called the semantic stack SEM, holds the "meaning" of the symbols in the first stack. That is, SEM(i) holds the "meaning" or "semantics" of the symbol in SYN(i). ... In any implementation of PL, these is also an associated semantic language, in which the semantic routines are programmed. This may be ... it really doesn't matter. By a semantic routine, we just mean a set of statements in the semantic language which is identifiable in some way. Each may be a separate procedure, each may be a single substatement of a large case statement, or the semantic language may provide a special "semantic label" to identify the beginning of a semantic routine." Compiler Construction for Digital Computers, David Gries, 1971, John Wiley and Sons, pg 167. "Calling Semantic Routines" Len Bullard Intergraph Public Safety clbullar@i... http://www.mp3.com/LenBullard Ekam sat.h, Vipraah bahudhaa vadanti. Daamyata. Datta. Dayadhvam.h -----Original Message----- From: Uche Ogbuji [mailto:uche.ogbuji@f...] Sent: Monday, June 04, 2001 10:36 AM To: Christian Nentwich Cc: Jonathan Borden; James Clark; Rick Jelliffe; xml-dev@l... Subject: Re: Type and Structure Re: ASN.1 and XML > > Yes, and I don't see how this contradicts James's point. Typing belongs > > in the semantic model and James points out that TREX and RELAX don't make > > the (IMO) mistake of interposing typing between the syntax and semantics. > > If you think it's a mistake, blame the compiler people who came up with > annotating syntax with semantic constructs. Personally, I think it's > quite a convenient way (that still leaves the issue of whether XSD > should include it unresolved though). The compiler people rarely make a neat break between syntactic and semantic processing. YACC has start : exp1 { exp_value = $1; } ; So the semantic constructs (implementation of behavior) is right in there with the grammar. I think that markup languages occupy quite a different space. The idea is to *separate* the data from the processing, which to me means that we can just blindly import ideas from compiler theory any more than we can from object-oriented development. -- Uche Ogbuji Principal Consultant uche.ogbuji@f... +1 303 583 9900 x 101 Fourthought, Inc. http://Fourthought.com 4735 East Walnut St, Ste. C, Boulder, CO 80301-2537, USA Software-engineering, knowledge-management, XML, CORBA, Linux, Python
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