Modulo Does Not Match Quotient
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Eleanor Bartle
Jul 1, 2026, 11:17:22 PMJul 1
to chez-scheme
On my local installation (10.4.1 on macOS arm64), the following expressions evaluate thusly:
> (quotient -1 2)
0
> (modulo -1 2)
1
> (+ (* (quotient -1 2) 2) (modulo -1 2))
1
That is, quotient truncates, but modulo assumes flooring quotient. Thus, the defining equation of quotient and modulo does not hold.Is this a mistake? A glitch? An implementation oversight? A highly unfortunate detail of R6RS?
Pierpaolo BERNARDI
Jul 2, 2026, 8:57:05 AMJul 2
to Eleanor Bartle, chez-scheme
The "matching" pairs are quotient / remainder, div / mod, div0 / mod0.
The procedures, quotient, remainder, and modulo are there for
compatibility with previous standards.
No mistakes, no oversights :)
https://www.scheme.com/tspl4/objects.html#./objects:s98
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The procedures, quotient, remainder, and modulo are there for
compatibility with previous standards.
No mistakes, no oversights :)
https://www.scheme.com/tspl4/objects.html#./objects:s98
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> To unsubscribe from this group and stop receiving emails from it, send an email to chez-scheme...@googlegroups.com.
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