Schematics and symbols are presented as different types of document to
the user, with different file extensions, icons and mime-types.
However, when they are loaded into a gEDA application such as gschem
for editing, they are internally represented in exactly the same way,
by the page type. The page is the top-level gEDA document
data type.
Internally, the main difference between a page for a schematic
and a page for a symbol is the types of schematic element they
are permitted to contain (see Objects). For example, a symbol is
not permitted to contain nets, buses, or instances of other symbols,
and a schematic is not permitted to contain pins.
Note: Although the restrictions on what types of primitive element schematics and symbols may contain are not enforced by the API, designs which violate these restrictions may cause the netlister not to work as expected.
Each page is associated with a filename, although the filename is
not required by the API either to be valid or to be associated with a
accessible file in the filesystem.
Pages are not garbage-collected; once you create a page, you are
responsible for making sure that it is disposed of when it is no
longer required.