Am I right in thinking that Prolog(s) don’t support named constants? To define: icd10hypertension = R03.0 we need to: icd10hypertension('R03.0'). ? But to use this, we need to f(A,B,C) :- icd10hypertension(X), patients(A, B, X). suffering runtime unification costs and readability? We wou…

Does this do what you want? :- module(codes, [code/2, code_/2]). % Lookup by Name or Icd10; throw domain_error if not found % (Does not backtrack of results - for that, use code_/2). code(Name, Icd10) :- ( code_(Name, Icd10) -> true ; domain_error(valid_name_or_code, code(Name, Icd10…

If i understand this correctly, all approaches discussed here suggest having a named constant that is retrieved during runtime – in one way or another – via predicate lookup. I guess this is always slower than a named constant in compiled languages where the symbol gets replaced during compile time…

[image] grossdan: So, to have “real” named constant in prolog would require some kind of extension – perhaps an extension of the macro facility. Not so much extension. Just use the macro mechanism for replacing some term. The only gotcha is that you somehow have to recognise the thing you …

[image] stuz5000: @peter.ludemann Thank you. This would thwart any static error analysis. I’m not sure this makes a difference in Prolog-land though, since it seems to be without many compile-time types. ::frowning_face: “We shape our tools, thereafter our tools shape us.” — either W. Churchi…

Re. Kowalski. Prolog is a very leaky abstraction of logic. Understanding ‘under the hood’ seems like a necessity. Every new language involves kicking the wheels to find out why it works the way it does. It would be helpful to find a Wiki/cookbook - an Effective Prolog in the same vein as effectiv…

[image] stuz5000: Does such an ‘Effective Prolog’ resource exist? Yes, it is called “The Craft of Prolog”. It is old but the language was getting old when it was written :wink: EDIT: very recently Jan shared a reference to the paper that inspired him to implement SWI-Prolog the way that he d…

Several people recommended term_expansion. Thank you it is a useful tool. I’m a little confused about how it works (more like, when it works). My understand is that file directives are things that are executed while the file loaded (or when it is compiled?). An the rests of a .pl file is composed…

[image] Boris: Can someone point me to the link again? The way I use to find such is looking in Useful Prolog references In there is a section for Papers which has Publications about SWI-Prolog . The paper is in there if it is the paper I am thinking you are referring.

[image] stuz5000: I’m a little confused about how it works (more like, when it works). If there were phases to learning term expansion I think it would have phase n. I am little confused. phase n+m. I am totally confused, but happier/more saddened. I can’t even tell which one. While th…

My understanding is that doing term_expansion(A, B) :- ... is defining another clause for the multifile term_expansion predicate. The compiler then, when reading in terms, calls term_expansion on the read-in term and if it succeeds, acts as if it had read in the “return” value instead.

Named constants?

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Named constants?

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