RiverWare 6.1: Unit Schemes

RiverWare 6.1: Value Display Attribute Schemes
Decisions, and implications, from the July 6, 2011 design meeting
Edit: 7-06-2011, Phil Weinstein, CADSWES.

Unit Schemes, General

In the user interface, this feature will be referred to as "Unit Schemes".
We will not support "column name" (actually, column label) matching criteria for unit scheme matching rules. We will match SlotColRefs only on: (1) containing object types (including account types and the two abstract reservoir types and "Exchange"), (2) slot names, and (3) unit types. As a result, only the first two of these four proposed scheme rule types will be supported. (This eliminates some of the expressiveness of the riverwareDB feature).
1. Unit Type scheme rules (only without containing object type)
2. Slot name-based scheme rules (with or without containing object type)
3. ~~Column name-based scheme rules~~
4. ~~Slot name and column name-based scheme rules~~
We confirmed the decision to serialize Unit Schemes using XML.

Unit Scheme Editor

We will use a QTreeWidget -- possibly a single level list OR a multiple level treeview -- to show the scheme rules. This is instead of the widget array initially proposed by Phil. If a multiple level treeview is used, it must be possible to switch to any of the key fields as the treeview root (first column) -- and it might make sense to support also a single level list view (to support comprehensive sorting).
Operations on Value Display Attribute Rules (i.e. rows in the QTreeWidget) will be implemented by discrete widgets operating on the selected rows. It will be possible to simultaneously change the Scale, Unit, Format and Precision values of multiple selected rows. The "Set Units" operation will be available only if the selection of rows includes exactly one unit type.
In the QTreeWidget, the currently configured Format and Precision will be depicted with an example prototype, e.g. of PI (or something), like "3.142" or "3.1416e+00".
No interactive widgets (nor pseudo-widgets, e.g. icon labels as push buttons), nor incell editing, will be needed within the QTreeWidget.

Unit Scheme GUI Controls

We're not going to put unit-scheme switch controls (nor menu items) with each of the slot display dialogs -- EXCEPT for the Open Slot Dialog which will support an override feature to show values using the Local Scheme (without regard to the "active" scheme). The "active" Unit Scheme will be managed only from one central place ....
Unit schemes will be managed from a new "Units" workspace menu which will look something like this ...

Units
     Unit Converter...
     -------------------- 
     Local Units
 (o) Wygilian Units
     Initialization Units
     U.S. Units 1
     U.S. Units 2
     Standard Units
     --------------------
     Edit Unit Schemes...

(The "Unit Converter..." menu item had been under the "Utilities" menu).

QUESTION: Maybe this, or a different framing could include also the "Show Commas in Numbers" checkable menu item (which is now under the Workspace menu).

We're not going to worry about the concern that the SCT supports the display of numeric values, optionally without showing units. (That is, there was a concern that this may be more of a usage liability since display units will become much easier to change). There had been a thought that, in that case, we would need to at least show the name of the current scheme somewhere in the SCT dialog. We're not deciding to do any such thing now.

Display Attribute Group Definitions

Unit Scale values will be limited to non-negative integral powers of 10 (for the mapped schemes). (This will be enforced only in the GUI, as we want to use a common data structure to support legacy Unit Scale values within slot configurations).
Display Formats: It is acceptable to provide only the "Float" and "Scientific Notation" via the mapped scheme mechanism. The "Integer" format will remain available (for now) in the "Local Scheme" (configurations on slots and slot columns).
Display Formats: will be encoded as just 'char' instead of as a two-character QString.

Other Features

Old style DMI: We will issue a single warning from old-style DMIs indicating the number of slots for which no units were available from the control file. (In that case, we will be using the "local" units configured on slots). We will also add an optional diagnostic generating messages for each such slot.
Batch mode will unconditionally support only the "Local Scheme".

--- (end) ---