Show HN: Prolog compiler and interpreter in pure JavaScript

prolog.jldupont.com

15 points by jldupont 10 years ago · 4 comments

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colanderman 10 years ago

    ?- X = 10.
    X = _
    no.

...this doesn't work like any Prolog I know. (Even defining equality manually as "eq(X, X)." doesn't work...)

dmytrish 10 years ago

Why? `?-` indicates that it's a query, it should not define anything.
- colanderman 10 years ago
  $ swipl ?- X = 10. X = 10. $ gprolog | ?- X = 10. X = 10 yes
  (a) The REPL should print the variable bindings which caused the query to succeed. (b) The query `X = 10.` should succeed trivially.
  I've been using Prolog on-and-off for close to a decade now and have implemented my own pseudo-Prolog (also in Javascript; was missing logic variables and extra-logical builtins). I tried to get pretty much any query to succeed in this interpreter and couldn't. This is not any kind of Prolog that I'm familiar with.
  - dmytrish 10 years ago
    
    Yep, I agree I was wrong (having too little experience in Prolog): variables are necessary to extract values from queries.