xslt - Why do indexes in XPath start with 1 and not 0?

Question

Some colleagues and I were comparing past languages we had programmed in and were talking about our experience with VBScript with its odd features such as 1-based index instead of 0-based indexes like almost every other language has, the reasoning being that it was a language for users (e.g. Excel VBA) instead of a language for developers.

Then someone said, "XPath also has 1-based indexes" which I couldn't believe until I found this article in which many reasons are given in favor of the 0-based approach including some from Michael Kay himself:

• "...zero-based indexing tends to make the index formulae simpler when accessing a multi-dimensional array with a one-dimensional array access expression"
• "when handling tables, or subscripting into strings, zero-based addressing would often be much more convenient"
• "...hardware addressing is not the only benefit of 0-based addressing ... it also makes computations easier..."

but then Michael Kay is quoted as concluding:

...1-based logic was the right choice for XPath and XSLT...because the language was designed for users, not for programmers, and users still have this old-fashioned habit of referring to the first chapter in a book as Chapter One...

Can someone explain that to me? (1) How is XPath designed for users? I can't imagine anyone who is not a developer wrangling with the syntactical rigidity of XPath or the declarative/functional-programming-aspects of XSLT. and (2) Why really did the creators of XPath go against the norm of modern programming languages by choosing a 1-based index?

Answer 1

Array and other collection indexes represent memory offsets, so logically enough they begin at zero. XML and XPATH indexes represent positions and counts, so logically enough they begin at one (and zero is therefore representative of "empty")