Dear SWI-Prolog user, SWI-Prolog 10.1.7 is ready for download. This release lands the long-running overhaul of Unicode handling — both in the source-language syntax and in the editor/terminal rendering — together with a handful of behaviour changes to align with the Unicode recommendations for…

[image] jan: MODIFIED: All Unicode symbol classes (Sm, Sc, Sk, So) and the connector/dash/other-punctuation classes (Pc, Pd, Po) are now treated as solo: BTW: There are some approaches to do it differently. Actually moving the weights from solo to graphic. So that Emoijs don’t need string…

[image] Johnny_Rotten: So that Emoijs don’t need string quoting most of the time Emoji are now solo. This means they do not needs quotes unless you have multiple adjacent, e.g., ?- atom_concat(🩶, 🩶, X). X = '🩶🩶'. The idea is that most Unicode symbols have a semantics on their own and just…

[image] jan: Please come with examples of sequences of Unicode symbols you’d like to be handled as an atom (without quotes). I don’t have some very prominent examples, I have only an example that shows that both solo and graphical have its perks. The problem is what to do with UNASSIGNED? …

Those are true concerns. As is, we accept P* and S* as solos. There is also a derived property called Pattern Syntax. That is a stable subset of P* and S*. The downside is that it has been frozen in 2005 and lacks several currency symbols, a lot of arrows, the emoticons, etc. I don’t know. …

[image] jan: Note there is a Prolog flag unicode_syntax_version that tells you the Unicode version used to generate the tables that drive the parser. Ah, ok, I see it came with this version 10.1.7. Oki Doki! [image] jan: There is a third category that has an assignment, but without a …

[image] Johnny_Rotten: Well there is a PRIVATE_USE category covering U+E000–U+F8FF, U+F0000–U+FFFFD and U+100000–U+10FFFD for example. I am currently mapping it to “invalid”, similar like UNASSIGNED I think private use and “unstable” are different things. And yes, also for SWI-Prolog priv…

[image] jan: I think private use and “unstable” are different things. The definition delivered by a KI is: An unstable Unicode code point generally refers to a code point that is either unassigned (reserved), a non-character, or private use. My “invalid” definition is indeed different. Whi…

[image] Johnny_Rotten: There is whole bunch of runtime semantics impact, that one can adopt when adopting Unicode. i.e. atom_length/2 , sub_atom/5 etc.. etc.. might undergo some revisions or clarifications. Some funny effect of “wobbly atoms” with single standing surrogates. Some atom_lengt…

[image] Johnny_Rotten: Well some encoding requires pairs. Like UTF-16. A pair then exists on the physical level of the encoding, you might not see it on the logical level of the encoding. SWI-Prolog deals with encoding at I/O. After the I/O, everything is a sequence of Unicode code points…

[image] jan: it is not allowed to specify surrogate pairs It is allowed in Java. You can write \uD83D alone. The compiler doesn’t bark, nor the runtime. What I noticed having some quick save format, i.e. qsave_program/2, can relief you from defining a Unicode syntax, for the bootstrap part…

Ann: SWI-Prolog 10.1.7

Releases

alanbur May 18, 2026, 1:37pm 17

See BUG: internal error in GUI debugger - #2 by alanbur

Topic		Replies	Views
Ann: SWI-Prolog 10.1.8 Releases	5	202	June 15, 2026
Unicode symbols, and a possible numerical paradox! Discussion	27	2354	June 27, 2022
Trouble with Unicode Help!	10	461	September 21, 2021
Issue with processing Unicode General bug	15	313	October 31, 2023
Ann: SWI-Prolog 8.4.2 (stable) Releases	0	1194	February 10, 2022

Ann: SWI-Prolog 10.1.7

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