Draft implementation of proposed syntax changes (feedback requested)

.gitignore

@@ -21,3 +21,4 @@ cov.xml
 
 # This can be generated in-tree. We never want to commit it.
 pydra/_version.py
+pydra/engine/_version.py

docs/input_spec.rst

@@ -174,8 +174,9 @@ In the example we used multiple keys in the metadata dictionary including `help_
    (a specific input field will be sent).
 
 
-Validators
-----------
-Pydra allows for using simple validator for types and `allowev_values`.
-The validators are disabled by default, but can be enabled by calling
-`pydra.set_input_validator(flag=True)`.
+`shell_arg` Function
+--------------------
+
+For convenience, there is a function in `pydra.mark` called `shell_arg()`, which will
+takes the above metadata values as arguments and inserts them into the metadata passed
+to `attrs.field`. This can be especially useful when using an IDE with code-completion.

pydra/design/__init__.py

@@ -0,0 +1,6 @@
+from .base import TaskSpec, list_fields
+from . import python
+from . import shell
+
+
+__all__ = ["TaskSpec", "list_fields", "python", "shell"]