On Thu, 12 Jun 2014, Florian Haftmann wrote:

This is an offspring from
http://fa.isabelle.narkive.com/QI1dxXvo/isabelle-quotient-type-command-fails

I do not recommend white space in theory names: over the years proper
naming conventions have been increasingly enforced for logical entities
like variable names etc.  The issue with theory names maybe just escaped
attention due to its almost extralogical nature.

Allowing white space would be definitely a move in the wrong direction. Theory names were indeed quite informal some decades ago, but have slowly gained a more formal and disciplined status, like any other logical entity with a canonical name space.

The transition towards properly qualified and authentic theory names is not yet complete, but this spring I got *almost* there. (The attempt was defeated by various technical side-conditions imposed by the still existing Isar TTY loop, as well as some unexpected problems with the HOL-Light importer.)


the fact that the quotient package would cut a name at white space
borders nevertheless seems strange to me and would deserve an inspection.

This is due to "slightly odd bundle trickery" as I called it in my change 745f568837f1, which also removes a deadly "handle _ =>". Note that I was cleaning up and robustifying other system interfaces in the usual way and passed-by accidentally (see also 8bedca4bd5a3).

The fragility exposed on this thread is caused by taking an internal long name, and scanning that again as outer token. This works under the assumption that names are (qualified) identifiers, which is almost always the case these days. The qualification prevents overlap with Isar keywords, unless people define very odd keywords themselves that look like long identifiers. An alternative is to produce quotes around the name, before parsing it again.

It is up to Ondřej if he wants to make this yet more robust -- there are more than 2 weeks left before the Isabelle2014-RC1 repository fork.


        Makarius
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