Re: [xsl] My XPath mistakenly referenced an element that doesn't exist and I got no error message ... is this bad language design?

["Graydon graydon@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

On Thu, Oct 14, 2021 at 03:17:08PM -0000, Michael Kay mike@xxxxxxxxxxxx scripsit:
> I've sometimes wondered whether a "soft" checker (lint-like) that warns you of potentially void paths (by reference to a schema and/or instance document) might not be a valuable tool.

Any kind of XSLT linter would be a fine thing to have.

> Or a run-time checker might be less complicated than a compile-time checker: Add an option selection="strict" at the xsl:transform level, and then
> 
> Document/foo is treated as one-or-more(Document)/one-or-more(foo)
> 
> while if you want zero-or-more(Document)/zero-or-more(foo)
> 
> then you have to use some new syntax like opt(Document)/opt(foo)
> 
> Even adding req() as a synonym for one-or-more() might be enough to encourage people to write req(Document)/req(foo) in order to get better diagnostics.

I prefer keeping the default behaviour of the XPath expression and
adding req().  This would be very handy for those "of course there's a
document, wait, oops" expressions.

> Or perhaps a "\" operator that behaves like "/" except the RHS is not allowed to be empty.

Overloading backslash seems a titch rash.  And this would be harder to
read than req() would be.


-- 
Graydon Saunders  | graydonish@xxxxxxxxx
^fs oferiode, pisses swa mfg.
-- Deor  ("That passed, so may this.")