Command abbreviations under RO3

[Boydie]

I've been trying to get my old software from BITD working both on real machines and emulators, and I've noticed something bizarre.

Under RO2 (at least in an emulator), things work fine.

Under RO3 (both emulator and real machines), I sometimes get the error "Bad file name 'Net:%Logon'".

After much trial and error, I've realised that this happens if file commands are abbreviated.
So, under RO2 "*L.<filename>", "*LO.<Filename>", and "*LOAD <filename>" all work. Under RO3, only *LOAD works; the abbreviated forms generate the error.
It happens after a clean boot, on any file. So it's not program-specific.

Is this a recognised phenomenon? Is there an easy workaround?

[SKS1]

Someone decided to make the alias search handle abbreviated commands in the early days (can't remember whether Arthur was afflicted); bad move IMO.

RISC OS 3 set up more aliases than RISC OS 2.

You could Unset alias$Logon

[Boydie]

Thank you!

You have no idea how much grief that issue's caused me this year (or how much work I now have ahead of me, putting "incompatible" software on multiple machines).
Wish I'd asked sooner!

[jgharston]

You should never ever ever ever ever ever ever ever ever ever ever ever ever ever embed abbreviations into released code, as you have ZERO knowledge of the OTHER PERSON'S machine that it will be run on. On your machine *D. may match DUMP, on my machine *D. may match DESTROY.

[IanJeffray]

You should never ever ever ever ever ever ever ever ever ever ever ever ever ever embed abbreviations into released code

Agree. Moreover, it may be arguable to use *%LOAD rather than just *LOAD so that you guarantee to bypass any Alias$

[sirbod]

Is there an easy workaround?

Code: Select all

*Set Alias$L. LOAD %*0

[BeebMaster]

I would definitely concur that using minimum command abbreviations should be avoided for any code that might find its way onto a different machine. The only real case for it would be if there is just simply insufficient memory for the code without using an abbreviation. That really ought never to happen on an Archimedes, but could happen on Beebs.

Is this an appropriate place to vent a long-standing gripe of mine: why on Earth did Acorn replace "*I AM" with "*LOGON" in RISC OS?

[wiggy]

why on Earth did Acorn replace "*I AM" with "*LOGON" in RISC OS?

Most of the command parsing and matching under RO is done by the OS itself (the module provides a table of commands, help strings, entry points, etc, and the OS does all the hard work), so the space in the middle breaks the system. The command would have to be just "*I" - which would then screw up the automated output of the *Help tables.

That said, the RO3 PRMs note that NetFS intercepts the Unknown Command service call to implement commands that are server-side, so it might have been possible to "special case" this one although it would be missing from the help.