Using Electric 3-2: Creating and Deleting Facets

Chapter 3: HIERARCHY

| ## 3-2: Creating and Deleting Facets |

### Facet Creation

Facets are created with the Edit Facet... command of the Facets menu.

| When the Edit Facet... command is used, a dialog of existing facets is presented. You can choose to show the facet in the current window, or create a new one. In addition, there are two options for filtering the list of facets. If there are cells with multiple versions, you can choose to see the old versions or ignore them. If there are facets from a "cell library", you can remove them from the list so that it shows only your design hierarchy.

To create a new facet, click on the "New Facet" button. This then presents a dialog in which the new facet name and its view can be specified. |

Facet names may not contain spaces, tabs, unprintable characters, or a colon. Uppercase and lowercase characters are not distinguished: The facet "UPPER" is the same as the facet "Upper." However, the form of capitalization that is used when a facet is first created is retained for all further use.

There are two ways to make a copy of a facet. The Duplicate Current Facet command of the Facets menu copies the facet in the current window to a new facet with a new cell name. You will be prompted for the new name. The New Version of Current Facet command also makes a copy of the facet in the current window. However, this copy is a "new version", which has the same cell name. The newly created facet is displayed in the window. Both of these commands work within the same library.

### Facet Deletion

| To delete facets, use the Delete Facets... command of the Facets menu. You will be given a list of facets and may delete any of them by selecting their name and clicking the "Delete" button. To make the list of facets easier to examine, three checkboxes are provided. "Show relevant facets only" limits the list to facets whose views are the same as the current facet. "Show old versions" controls whether old versions of facets are included. "Show facets from Cell-Library" controls whether facets from cell libraries are included.

When deleting a facet, there cannot be any instances of this facet, or the deletion fails. As a side effect of failure, you are shown a list of all other facets that have instances of this, so you can see the extent of its use. To find out whether a facet is being used elsewhere in the hierarchy, use the List Facet Usage... subcommand of the Facet Information command of the Facets menu.

Because Electric is able to keep old versions of facets, deleting the latest version will cause an older version to become the "most recent". Old versions are those whose facet names include the ";VERSION" clause indicating that there is a newer version of this view of the cell. For example, if you have facet "Adder" and an older version "Adder;1", then deleting "Adder" will cause "Adder;1" to be renamed to "Adder". This might make you think that the deletion failed, because there is still a facet called "Adder", but this facet is actually the older (but now most recent) version.

To clean-up old and unused versions of facets, use the Delete Unused Old Versions command of the Facets menu. Any such facets that are no longer used as instances in other facets will be deleted from the library. You will get a list of deleted facets, and it is possible to undo this command.

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