Programmer's Guide > Programming and Scripting Techniques > Line Numbering in Arbortext Editor and Arbortext Publishing Engine > Line numbering application building reference > The Layout file and document type > Floating structures
  
Floating structures
A float is a vertical container. It holds galley material that does not appear in sequence with the galley but rather in one of the many float areas available in the page layout. These areas are the top or bottom of the page, the top or bottom of any span, and the top or bottom of any column.
Floating material belongs to one of many float classes, and within a class multiple floats retain their galley order. For example, footnotes are floats that belong to the footnote class, and they appear in the page layout in the same order as they originally appeared in the instance.
The oid attribute indicates the element that starts the float.
The class attribute indicates the float class. The class also contains a float occurrence modifier. Repeating floats may appear many times, while once floats may only appear once. Applications may be written to ignore repeating floats and process once floats according to the class name.
The flid attribute (float identifier) provides a unique number for each float in a class.
The pagetype attribute defines the relationship between a float and its point of reference.
The width attribute specifies the width of the content.
<!ELEMENT Float ((Row | Line)*)>
<!ATTLIST Float
oid %oid; #REQUIRED
class CDATA #IMPLIED
flid CDATA #IMPLIED
pagetype CDATA #IMPLIED
width %dimen; #IMPLIED >