4 ms·

I've used Python a lot more than Groovy but one thing I find myself missing from Python and other scripting languages since I discovered Groovy is the ability f

I've used Python a lot more than Groovy but one thing I find myself missing from Python and other scripting languages since I discovered Groovy is the ability for a standalone script to retrieve its dependencies on startup. What this means is that if you put @Grab(group='foo', module='bar', version='1.0.0') at the top of randomscript.groovy you will have bar available to import by the time the script starts.

azaras 10y ago
You could use: import pip pip.main(['install', 'bar'])
- jonesetc 10y ago
  Please don't though.
- networked 10y ago
  It's not this simple. That code will only work if you are root or in a virtualenv — and having to create a virtualenv manually contradicts the idea of a self-contained, standalone script that manages dependencies on its own. To install bar as a non-root user you will have to do import pip pip.main(['install', '--user', 'bar']) which throws an error, e.g., if bar is already installed, meaning you will have to wrap the calls to pip.main() in a "try" block and differentiate between the types of errors they throw. The above already makes it noticably less convenient for a script to manage its own dependencies. The killing blow, however, comes form the fact that pip won't let you install multiple versions of the same package in parallel: the most recently installed version overwrites the previous one. This means that a script that relies on a per-user package store can only be safe if it checks the version of every package it uses and replaces it if needed each time it is run. This can a take a long time and is error prone (what if your Internet connection goes down?) but the alternative is simply to deal with the brittleness. I can see this being solved for Python but the solution will probably involve automatically creating and caching per-script virtualenvs. For now, though, something like PyInstaller (i.e., binaries) remains more practical if you want to distribute standalone Python scripts.
  - azaras 10y ago
    I am sorry I made a mistake. You are right. Thanks for the explanation.
    - networked 10y ago
      No worries!
  - raiph 10y ago
    Aiui Perl6's module related design elements allow for this though I don't know if anyone has implemented what you describe. I'll be happy to discuss this further if anyone shows interest.
seanp2k2 10y ago
You might enjoy Go
vorg 10y ago
Apache Groovy's original use case was scripting, so there's many features like that which makes Groovy be Bash for the JVM. It was based on Beanshell originally, but with closures and collections syntax added. Just don't try building any actual systems with Groovy -- do that in a language designed from the ground up for performance, e.g. Java, Scala, or Kotlin.
networked 10y ago
s/missing from Python/missing in Python/

azaras 10y ago

You could use: import pip pip.main(['install', 'bar'])

jonesetc 10y ago
Please don't though.
networked 10y ago
It's not this simple. That code will only work if you are root or in a virtualenv — and having to create a virtualenv manually contradicts the idea of a self-contained, standalone script that manages dependencies on its own. To install bar as a non-root user you will have to do import pip pip.main(['install', '--user', 'bar']) which throws an error, e.g., if bar is already installed, meaning you will have to wrap the calls to pip.main() in a "try" block and differentiate between the types of errors they throw. The above already makes it noticably less convenient for a script to manage its own dependencies. The killing blow, however, comes form the fact that pip won't let you install multiple versions of the same package in parallel: the most recently installed version overwrites the previous one. This means that a script that relies on a per-user package store can only be safe if it checks the version of every package it uses and replaces it if needed each time it is run. This can a take a long time and is error prone (what if your Internet connection goes down?) but the alternative is simply to deal with the brittleness. I can see this being solved for Python but the solution will probably involve automatically creating and caching per-script virtualenvs. For now, though, something like PyInstaller (i.e., binaries) remains more practical if you want to distribute standalone Python scripts.
- azaras 10y ago
  I am sorry I made a mistake. You are right. Thanks for the explanation.
  - networked 10y ago
    No worries!
- raiph 10y ago
  Aiui Perl6's module related design elements allow for this though I don't know if anyone has implemented what you describe. I'll be happy to discuss this further if anyone shows interest.

seanp2k2 10y ago