Help with Existence Error (Procedure -->/2)

[d-gaston]

Hello,
I am trying to run some of the DCG examples and am not having any luck. I ran use_module(library(dcgs)). in the top level and it answered true., and then I tried running the example in the the documentation https://www.scryer.pl/dcgs as --> []. and I get error(existence_error(procedure,(-->)/2),(-->)/2). I am able to load predicates from other libraries (for example, char_type from charsio.

I am running the Linux (Ubuntu 22.04, 64 bits) release, version df41eb1. My apologies if I am missing something obvious.

[UWN]

Apparently, you entered as --> [] on the top level like so:

?- use_module(library(dcgs)).
   true.
?- as --> [].
   error(existence_error(procedure,(-->)/2),(-->)/2).   % that's fine
?- [user].
as --> [].
as --> "a", as.

?- phrase(as,L).
   L = []
;  L = "a"
;  L = "aa"
;  L = "aaa"
;  L = "aaaa"
;  ... .

[d-gaston]

Thank you!