[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] What is an integer? (was: Re: XML Quiz)
Roger L Costello <costello@mitre.org> writes: > Is '4' '4' an integer? > > Clearly it is not. It is a string that consists of two characters. If you are going to make fine distinctions of this kind, then you will do better to be more careful. What you exhibit in your question is, in the notations that shape most readers' instincts in this area, not a string but a pair of single-character strings. > Recap: > 1. 44 is not an integer. It is a string. No, on the contrary, in ordinary usage 44 is quite clearly an integer, and the string "44" is a numeral, one of many ways of writing down the number whose other names include (11 * 4) and (21+21). > 2. XML does not contain integers (or floats or booleans or URLs or > anything else). XML only contains a sequence of characters. You seem to be assuming a particular definition of XML that allows you to see what an XML document is and what it's not, but so far you haven't shared that definition with your readers. Is your definition based on anything that can be found in the XML spec? What does the XML spec say an XML document is? What you say about the role of a schema seems plausible enough (assuming that the validator is invoked in a way that leads it to validate the element you show against the element declaration you show), as far as it goes; it's an instance of quite a general rule: bits are assigned meaning based largely on context. It's also an instance of an even more general observation: nothing in our machines ever contains an integer (or for that matter a string of characters), since integers are abstract objects and machines are physical objects. Our machines only ever contain and operate on representations of things like integers. It is convenient to exploit metonymy and allow ourselves to speak of a particular field of bits as "being" an integer rather than "representing" an integer, but that is just a manner of speaking, not a coherent account of programming-language semantics. If we are interested in speaking precisely and carefully, then it is just as much a mistake to think that a 64-bit field consisting of 58 zeroes followed by the bits 1, 0, 1, 1, 0, 0 in that order "is" an integer as it is to thing that two adjact eight-bit fields each containing the bit string 00110100 "is" an integer. -- C. M. Sperberg-McQueen Black Mesa Technologies LLC http://blackmesatech.com
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