So, just for funs and learning, I started following a build your own text editor tutorial using swi prolog… And I must say that I am really enjoying this ! So I was wondering if anyone has ever attempted to write a command line program in prolog ? Here are some random notes about my experience: t…

[image] kwon-young: Does anyone know of a datastructure more suitable for this use case ? I’d consider going for a an array of strings or maybe atoms. For an array you use a compound term, e.g. functor(Lines, lines, 1000). Now you have some options. For an updated line you can copy th…

[image] kwon-young: Does anyone know of a datastructure more suitable for this use case ? I believe that the “rope” data structure is often recommended for this sort of thing, which Eshel Yaron has implemented as a SWI-Prolog pack .

Another simple data structure would be a list zipper, basically a pair ([Front],[Current|Tail]), where Current is the line with the cursor, Front is a reversed list of all lines preceding it and Tail a normal list of all the following lines. That deals gracefully with changes near the cursor, and s…

Thank you all for your replies. It’s very interesting to see the different suggestions. [image] jan: I’d consider going for a an array of strings or maybe atoms. For an array you use a compound term, e.g. Jan suggestion has a very C feeling to it ^^ By the way, the original tutorial is doin…

One slight inconvenience is that you loose the ability to do absolute indexing, unless you also keep the index of the current line ? Yes, I suppose it would be practical to keep some statistical data with it, e.g. the number of lines in Front, and probably also the number of characters.

[image] kwon-young: almost all of my predicates are actually DCGs Let me put in a plug for “ extended DCGs ” in pack(edcg) … these allow multiple accumulators and the accumulators can do custom things, such as symbol tables. Speaking of symbol tables, I use rbtrees , which have O(log N) perform…

Writing a text editor in prolog

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Writing a text editor in prolog

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