The lowest level construct, the subfield, shall only contain one elementary data item, for example, one colour coordinate or one symbology instruction. Formatted subfields, such as the subfields that contain the vector image definitions, shall be further resolved by an application program. In this specification, subfields are not divisible.
The field tag is a unique 4 character field type which links an instance of a field type in a data record to the data descriptive record that defines the syntax of that field type.
The subfield label is a 4 character label, present only in the data descriptive record of a file, required to identify the subfields within a field type. A label preceded by an "*" signifies that that subfield, and any subsequent ones, repeat within the field. This, therefore, indicates the presence of an array or table, for which the subfield labels provide the column headings.
Subfield data type codes uses data types as follows:
A signifies character data,
I signifies implicit point representation (integer),
R signifies explicit point representation (real or float),
An extent of X(n) indicates a fixed length subfield of length n. An extent of X(1/15) indicates a variable length subfield terminated by the delimiter "1/15" (that is ASCII 1F hexa-decimal or 31 decimal).
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PresLib Edition 4.0.0 Part I September 2014
Directory: iho pubs -> draft pubs -> PresLib e4.0.0 -> Part I
Part I -> Presentation library
