Editor modules for GUI integration

Overview

The ARTS Python GUI provides per-type editor modules for workspace group values. These modules live in python/src/pyarts3/gui/edit/ and are used by the GUI (and can also be called directly) to edit values in a small, focused dialog.

The goal is to give developers a clear, consistent pattern for adding or adjusting editors as the set of supported ARTS types grows.

Design Pattern

Each editor module is named after the ARTS workspace type it handles and exports a single function edit(value, parent=None):

__all__ = ["edit"]

def edit(value, parent=None):
    """Edit a <WorkspaceGroup> value.

    Parameters
    ----------
    value : ~pyarts3.arts.<WorkspaceGroup>
        The value to edit
    parent : QWidget, optional
        Parent widget for the dialog

    Returns
    -------
    <WorkspaceGroup> or None
        The edited value if accepted, None if cancelled
    """
    # Build QDialog UI and return new value on accept

Dispatch and Fallback

  • The dispatcher pyarts3.gui.edit.edit(value, parent) looks up an editor submodule matching type(value).__name__ and calls its edit function if available.

  • If no specialized editor is found, the Generic editor is used as a fallback. It offers a type-preserving eval UI where the user enters an expression that is passed to the original type’s constructor (TypeName(<expr>)). This makes it possible to edit uncommon types without writing a dedicated editor.

  • For safety and consistency, the Generic editor first attempts to delegate to a specialized editor module if one exists; the eval UI is strictly a fallback.

Editor Guidelines

  • Signature: edit(value, parent=None) returning the edited value or None.

  • Dialogs should use QDialog.exec_() and return values only on QDialog.Accepted.

  • Preserve ARTS types. If the editor creates intermediate Python lists or numpy arrays, coerce back to the original type, e.g., type(value)(data).

  • Keep the UI minimal and focused on the specific type.

  • Provide friendly error messages and avoid crashing on invalid input.

  • Respect the optional parent QWidget for modality/ownership.

Adding a new editor

  1. Create editor module at pyarts3/gui/edit/MyType.py.

  2. Implement a small QDialog to edit the value.

  3. Reconstruct the type on save, e.g., type(value)(payload).

  4. Add from . import MyType to pyarts3/gui/edit/__init__.py:

    from . import MyType

  5. Verify via GUI double-click or by calling the editor in Python:

    import pyarts3.gui.edit as edit
new_value = edit.edit(old_value)

Examples and References

  • Simple scalars: Numeric.py, Index.py, String.py

  • Arrays and matrices: Vector.py, Matrix.py

  • Fixed-size vectors: Vector2.py, Vector3.py, Stokvec.py

  • Fallback: Generic.py (type-preserving eval)

These examples illustrate type preservation, validation, and concise UI design.