Docs/document environment variables (#746)

I would like to extend this document, but i'm done for now. Just wanted
to get the fixes in and document the variables some where

docs/advanced/advanced_tasks.md

@@ -30,7 +30,7 @@ configure = { cmd = [
 build = { cmd = ["ninja", "-C", ".build"], depends_on = ["configure"] }
 
 # Using environment variables
-run = "python main.py $PIXI_PACKAGE_ROOT"
+run = "python main.py $PIXI_PROJECT_ROOT"
 set = "export VAR=hello && echo $VAR"
 
 # Cross platform file operations

docs/environment.md

@@ -0,0 +1,19 @@
+---
+part: pixi
+title: Environment
+description: The resulting environment of a pixi installation.
+---
+
+# Environment variables
+The following environment variables are set by pixi, when using the `pixi run`, `pixi shell`, or `pixi shell-hook` command:
+
+- `PIXI_PROJECT_ROOT`: The root directory of the project.
+- `PIXI_PROJECT_NAME`: The name of the project.
+- `PIXI_PROJECT_MANIFEST`: The path to the manifest file (`pixi.toml`).
+- `PIXI_PROJECT_VERSION`: The version of the project.
+- `PIXI_PROMPT`: The prompt to use in the shell, also used by `pixi shell` itself.
+- `PIXI_ENVIRONMENT_NAME`: The name of the environment, defaults to `default`.
+- `PIXI_ENVIRONMENT_PLATFORMS`: The path to the environment.
+- `CONDA_PREFIX`: The path to the environment. (Used by multiple tools that already understand conda environments)
+- `CONDA_DEFAULT_ENV`: The name of the environment. (Used by multiple tools that already understand conda environments)
+- `PATH`: We prepend the `bin` directory of the environment to the `PATH` variable, so you can use the tools installed in the environment directly.

docs/stylesheets/extra.css

@@ -7,6 +7,11 @@
   font-weight: normal;
 }
 
+.md-typeset *:not(pre) > code {
+  /* Dimmed 30% of the main yellow color (ffec3d)*/
+  color: #b3a52b;
+}
+
 .md-typeset h1 {
   color: #ffec3d;
 }

examples/ros2-nav2/pixi.toml

@@ -7,7 +7,7 @@ channels = ["conda-forge", "robostack-staging"]
 platforms = ["linux-64", "osx-arm64", "osx-64"]
 
 [tasks]
-start = {cmd="export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:$PIXI_PACKAGE_ROOT/.pixi/env/share/turtlebot3_gazebo/models && export TURTLEBOT3_MODEL=waffle && ros2 launch nav2_bringup tb3_simulation_launch.py headless:=False"}
+start = {cmd="export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:$PIXI_PROJECT_ROOT/.pixi/env/share/turtlebot3_gazebo/models && export TURTLEBOT3_MODEL=waffle && ros2 launch nav2_bringup tb3_simulation_launch.py headless:=False"}
 
 [dependencies]
 ros-humble-desktop = "*"

mkdocs.yml

@@ -74,6 +74,7 @@ nav:
   - Basic Usage: basic_usage.md
   - Reference (CLI): cli.md
   - Configuration: configuration.md
+  - Environment: environment.md
   - Vision: vision.md
   - In-depth:
     - Authentication: advanced/authentication.md