(If you reply with something along the lines of "But it's easier to write a DTD and feed it through a generic validator than it is to roll your own CSV validator", please provide concrete evidence to back this up. Based on the few examples I've seen, DTDs seem to be a programming language unto themselves, no less complex (and far more verbose) than the level of perl code that would be required for this task.)

you could just as easily write external software to validate that CVS as well

Not quite. First if you are dealing with sloppy providers they might not include the CVS headers and then how are you going to know which field is missing when that happens?

Then really, DTDs are written using a language designed for language description. You can't really compare it with a programing language, more with the table description part of SQL, or with lex+yacc. For a concrete evidence You can have a look at the IEEE Standards DTD (be warned though, loading the DTD crashes my Mozilla) and tell me how easy it would be to write a Perl program that would parse and validate data tagged according to that DTD (it's SGML, but XML is just the same). I know I'd rather write the DTD and let any parser do the job!

esper++, my thoughts. You know how it is with function prototypes.. there comes a point where the compiler simply can't be clever enough to check the validity of arguments and you have to check at runtime. XML vs CSV is similar.

Makeshifts last the longest.

Did you actually think that I was suggesting that XML validates itself? I use XML::LibXML to do that. One method call, validate(). Sure looks easier than writing your own edits for CSV's. Face it, I am right. You are wrong.

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I like chicken.

One method call, validate().

And what, in the absence of a DTD, is the XML validated against? Simply that the brackets are all matched and it's syntactically valid? That's the same level of "validation" that you get by counting the commas in each row of a CSV file. Neither one tells you whether the data is formatted appropriately for your intended use.