PicoMite 6.00.02 prospectus

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robert.rozee
Guru

Joined: 31/12/2012
Location: New Zealand
Posts: 2552
Posted: 01:44pm 16 Jan 2025      

  twofingers said  
  matherp said  I've also played with this - does it make sense?
Note that BYVAL is effectively a unary operator ...

Do we need that? Isn’t that identical to
a%=7
Print double((a%))
Print a%
Print double(a%)
Print a%

Function double(i%)
 i%=i%*2
 double=i%
End Function


this also works:  

Print double(--a%)

but unfortunately this does not:  

Print double(+a%)


my vote would be for +a% for the reasons that:

+ using it adds just a single token to the program's length rather than two tokens,

+ applying the same rule to + as is applied to - would reduce the size of and simplify the interpreter,

+ it is mathematically correct.

one could even argue that the error produced:

>
> Print double(+a%)
Error: Expression syntax
>

represents a... bug.   if - is accepted as a valid unary operator that changes sign, then surely + must be accorded the same status, as a unary operator that does not change sign.

as a bug fix, this could even be a good excuse for releasing a new revision of mx170 mmbasic    


cheers,
rob   :-)


addendum: look what works on the mx170:

>
> ?+-+2
-2
> ? ---2
-2
> ? +--2
2
> ?--+2
2
>


addendum 2: looks like the code that evaluates expressions for print accepts '+' as a unary operator, but the function parser does not.
Edited 2025-01-16 23:58 by robert.rozee