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A comprehensive list of Prolog instantiation modes is given in a previous question: Meaning of instantiation mode indicators in arguments of Prolog predicates.

However, I have not been able to find any reference to or explanation about the double plus (++) instantiation mode in ECLiPSe Prolog. An example predicate in the ECLiPSe docs that uses the '++' mode is setval(++,?).

Does anyone know what the meaning is of this mode?

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Simon Slangen
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1 Answers1

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This mode is described in http://eclipseclp.org/doc/bips/kernel/compiler/mode-1.html as having the following meaning: ++ The argument is ground.

jschimpf
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migfilg
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