CHR # operator

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Anne Ogborn

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Jan 10, 2019, 9:50:20 PM1/10/19
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Can anybody explain the # operator in CHR in SWI-Prolog?

Falco Nogatz

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Jan 14, 2019, 11:46:51 AM1/14/19
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Hi Anne,

where have you stumbled over the # operator in CHR?

Best,
Falco

Anne Ogborn

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Jan 14, 2019, 5:07:53 PM1/14/19
to Falco Nogatz, SWI-Prolog
In the sources, it's defined as an operator.


On this page

http://www.swi-prolog.org/pldoc/man?section=SyntaxAndSemantics

apparently they're somehow associated with rule id's. And it's unclear
what the rule id's do at all

See also the passive pragma, which refers to it.


::Annie is here, playing nicely. She's reading the CHR sources to her dolly..::

Alan Baljeu

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Jan 29, 2019, 7:04:50 PM1/29/19
to Anne Ogborn, Falco Nogatz, SWI-Prolog
Rule IDs do absolutely nothing in the SWI implementation.  I think the only use I've had for # is the passive operator, which is a little like a ! cut in SWI.  If used correctly it makes the program more efficient.  If used wrongly, it makes the program misbehave.

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