

Ask HN: Why can't webapps agree on unacceptable unsername characters? - why-el

For instance, some webapps I sign up for accept dashes, some others don't. I was wondering whether there are factors that affect or play a role in these decisions.
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officialchicken
Which alphabet - English, Cryllic, Katakana, or Hebrew?

Sometimes I've accepted only valid base-64 characters for transport reasons -
RFC 4648. Other times only email characters - RFC 5322. A couple of times I
was limited to the restrictions of the underlying OS or platform. Some
runtimes are ascii-centric and require extra care dealing with unicode or
extended characters. IBM mainframes / gateways can have endian issues.

And sometimes it's just trivial - reusing a regex from a previous project -
for example.

EDIT: wrong word in first line.

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chc
The same reason they don't agree on much else: They're made by different
people for different people with different purposes using different
technologies.

For perspective: Graphical PCs have been in common use for about two decades
now and we still can't even agree on what to call the quit or preferences
commands _or_ where to put them.

