Re: [xml-dev] Preoccupation with zero, empty strings, empty elements,emp

On Sat, Dec 7, 2013 at 8:34 AM, Costello, Roger L. <costello@mitre.org> wrote:

Hi Folks,

When was the last time you went to the store to purchase zero oranges?

Well, frequently. The last time I went to the store I purchased zero oranges, in fact. But I admit I did not go there with that purpose.

When was the last time you created an XML document to have zero elements?

Such a document is not well-formed.

- Many programming languages do not
support records with zero fields

This works in C, at least as implemented by gcc 4.8.1. Turning on -Wall -pedantic triggers a warning. It's useless, anyway.

- Many programming languages do not
support arrays with zero elements

This also works in gcc 4.8.1. Turning on -Wall -pedantic tells us that the zero-size array violates ISO C but is permitted as a gcc extension.

- Many programming languages do not
support variable definitions with zero
variables

This triggers a gcc warning by default, as it is useless, but it works.

- In some programming languages the
syntax for calling a routine with zero
parameters differs from that for a
routine with one or more parameters

I'm not familiar with any languages that make this mandatory. In Algol 68 it's *possible* to call a procedure with no parameters without using (), but this is a type coercion from (say) "proc-returning-int" to "int".

- Many compilers refuse to compile a
module that defines zero names

This works by default in gcc, but -Wall -pedantic again says that ISO C forbids it, probably because of its uselessness.

- No parser generator can produce a
parser for the empty language (the
language with zero strings)

This preoccupation with empty strings, sets, languages, etc. is not frivolous, since it is well-known that the ease with which a system handles empty cases is a measure of its cleanliness and robustness.

Not always.

--
GMail doesn't have rotating .sigs, but you can see mine at http://www.ccil.org/~cowan/signatures