Cant import

[Daemon-ser]

I got a problem when using ‘pyswip'. Maybe the function re.search miss an argument(‘swi_ver’) ? Is it necessary to input the version of swi-prolog? It never happened to me before.

[Freakwill]

same problem. it must be a bug. just add swi_ver into re.serearch

[zhanwenchen]

Same problem. The code here makes no sense because re.search(regex_pattern, string_to_search) takes two arguments but on line 310 here there is only the pattern argument, so of course the code raises: https://github.com/yuce/pyswip/blob/f7c1f1e8c3a13b90bd775861d374788a8b5677d8/pyswip/core.py#L306-L314

Another critical error in code is that the walk function has inconsistent return types. Although walk's docstring specifies a str return, the _findSwiplMacOSHome function expects a (res_path, back_path) return from walk. The walk function can even return a None: https://github.com/yuce/pyswip/blob/f7c1f1e8c3a13b90bd775861d374788a8b5677d8/pyswip/core.py#L274-L303

Here's the referenced _findSwiplMacOSHome function which expects walk to return a (str, str) return. https://github.com/yuce/pyswip/blob/f7c1f1e8c3a13b90bd775861d374788a8b5677d8/pyswip/core.py#L317-L355

[zhanwenchen]

@yuce After some digging, I think a deeper problem is that pyswip doesn't support SWI-Prolog 8.x, because the version-seeking functions in pyswip/core.py look for libswipl.xx and libpl.xx but those no longer exist starting with swipl 8.0.1. See the official list of all stable releases.

[zhanwenchen]

I finally found a solution: the only SWI-Prolog version that has worked for me is Homebrew's swi-prolog 7.6.4 (latest 7.x.x stable release). Because Homebrew does not keep track of different versions of swi-prolog, I had to really dig to find the old 7.6.4 "formula". Now it works with the current version of pyswip (0.2.8).

So remove your current SWI-Prolog install (and remove any associated PATH editing) and brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/09a94009142a6265b0b8e322463100610aeda964/Formula/swi-prolog.rb and call it a day.

Caveat: This approach will not let you use some of the packages, such as library(process) or library(http/json). To do this, you can still install the macOS app, but you have to manually install and relink the libncurses.6.dylib in order for PySwip to be able to find it, like this:

brew install ncurses # Specifically install this library
sudo find / -name "libncurses.6.dylib" # You'll see an entry in /usr/local/Cellar/ncurses/6.1/lib/libncurses.6.dylib or something like that in /.../Cellar/ncurses/ (Homebrew folder)

# Now go relink the libswipl.dylib to depend on the newly installed `ncurses` library
cd /Applications/SWI-Prolog.app/Contents/swipl/lib/x86_64-darwin15.6.0 # The "darwin" version may vary depending on your OS/SWI-Prolog version

# You'll see that it is linked against a fake /opt/local/lib/libncurses.6.dylib which doesn't in fact exist
otool -L libncurses.6.dylib

# Now check the top-level lib, libswipl.dylib, it should show a "@executable_path/../swipl/lib/x86_64-darwin15.6.0/libncurses.6.dylib" or something like that depending on your version.
otool -L libswipl.dylib

# Now replace the fake with the real by actually modifying the top-level lib, libswipl.dylib. Contrary to intuition, the way linking works in macOS is that you can only modify the depending library, so libswipl.dylib instead of libncurses.6.dylib.
install_name_tool -change @executable_path/../swipl/lib/x86_64-darwin15.6.0/libncurses.6.dylib /usr/local/Cellar/ncurses/6.1/lib/libncurses.6.dylib libswipl.dylib

# Now you'll see that libswipl.dylib has been successfully modified:
otool -L libswipl.dylib

[akshika47]

@zhanwenchen Thank you. This helped me.

[andreaBelmont]

hello, any chance that we can see this bug fixed?

[akshika47]

Good point @andreaBelmont. I am happy to help as well.

[drskuce]

I tried to hack this file on mac for latest swi 8.0.3 but after 1 hour I decided I didnt want to get into this

could someone fix this so us mac people can get back to work??

thanks

DS