The IPF tag language is similar in structure and syntax to the Generalized Markup Language (GML) used by IBM's Document Composition Facility* (DCF*) product. Source files are simple ASCII text files, and can be created using any normal text editor.
Tags are embedded in the files simply by inserting the tag into the text at the required point. For example, this document was created and formatted using GML tags, and the opening sentences of this chapter were created using the format shown in Figure "IPF Tag Language Example".
Note that the chapter heading is preceded by a "header level 1" tag which causes the header text to be formatted in a particular manner. Similarly, the header is followed by a "paragraph" tag which caused a new paragraph to begin. The formatting of the text within the source file is not significant; there is no requirement for a tag to begin at the left margin, or for each tag to begin on a separate line. A developer may organize the source files in the most appropriate manner for readability.
The first statement in a source file must be a :userdoc tag, and the last statement must be a :euserdoc tag. These tags are required by IPF. Comments may also be imbedded within a source file using the :* tag; comments are ignored by the IPF compiler, and do not appear in the formatted text.
A complete description of the formatting tags available under the IPF tag language is beyond the scope of this document. Some examples are given in the remainder of this chapter, and each tag is described in detail in the IBM OS/2 Version 2.0 Information Presentation Reference.