Use environment variables in F# directives

Question

In FSI, is it possible to run something like

#I @"%APPDATA%/npm/node_modules/blabla/bin/"

instead of

#I @"C:/Users/username/AppData/Roaming/npm/node_modules/blabla/bin/"

Any other options to make it not sensitive to username?

Nah, lots of other stuff depends on it being installed globally — Mikhail Shilkov, Nov 05 '17 at 21:56
Can you extract and combine the Path programatically: https://stackoverflow.com/questions/9709269/difference-between-specialfolder-localapplicationdata-and-specialfolder-appli — s952163, Nov 06 '17 at 05:10

Gene Belitski · Answer 1 · 2017-11-06T13:51:46.260

1

Not likely you can use environment variables in #I FSI directives.

However you may make your package installation agnostic of user name by using the trick with __SOURCE_DIRECTORY__ built-in identifier similar to one I've described in this SO answer:

create a file anchorfsi.fsx with the single line of code
```
#I __SOURCE_DIRECTORY__
```
and put it into the directory %APPDATA% points to
add to the command line starting your FSI the term
```
--load:%APPDATA%\anchorfsi.fsx
```

Now you can use relative paths in your #r directives.

Just for illustration I put into directory associated with my user profile a folder testlib containing FSharp.Data.dll. The snip below shows how it gets referenced from FSI using the outlined above technique:

edited Nov 06 '17 at 13:51

answered Nov 06 '17 at 13:19

Gene Belitski

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Thanks for the suggestion. Can I trick VS Code in a similar way? – Mikhail Shilkov Nov 06 '17 at 14:06
Do not use VS Code so dunno, but VS 2017 can be tricked in quite a similar manner. Let me know if you'd be interested and I'll update my answer with specifics. – Gene Belitski Nov 06 '17 at 15:58

Use environment variables in F# directives

1 Answers1