External Stages

fud supports using stages that aren't defined in its main source tree. These are known as 'external stages' and the provide a mechanism for projects using Calyx to take advantage of fud. You can register an external stage with:

fud register stage_name -p /path/to/stage.py

Once an external stage is registered, it behaves exactly like any other stage.

You can remove an external stage with:

fud register stage_name --delete

The following defines a stage that transforms MrXL programs to Calyx programs.

{{#include ../../frontends/mrxl/fud/mrxl.py}}

External stages must define default values for configuration keys using the Stage.defaults() static method and the name of the stage using the static name field.

Stage Configuration

Like normal stages, external stages can have persistent configuration information saved using fud config.

To add persistent stage configuration, run:

fud config stages.<stage-name>.<key> <value>

To dynamically override the value of a field during execution, use the -s flag:

fud e -s <stage-name>.<key> <value> ...

The override order for stage configuration is:

1. Dynamic values provided by -s.
2. Configuration value in the fud config.
3. Default value provided by Stage.defaults()