A Web 68 file is a long string of text which has been divided, more or less arbitrarily, into individual lines. The exact line boundaries are not critical, so that you can chop up the input file in any way you wish. The end of a line is regarded by weav as a blank space. However, Algol 68 program source code is very flexible, so weav will try to respect your layout within certain bounds.
Web 68 contains its own command language which is described in the following sections. Subsection 3.9 gives the definitive list of commands (there are no undocumented commands). Thus, to write a program using Web 68, you must be familiar with three languages:
As you write a program using Web 68, you should be aware both of the documentation and of the program you are writing: that is, you should be aware of the different actions that tang and weav will perform on your document. See sections 3.2.1 and 3.2.2 for an overview of what each program does.
A Web 68 document consists of a number of sections, each of which starts with a section command and can contain an HTML part, a definition part or an Algol 68 part. Any of the parts can be omitted. Indeed, a section command can be followed immediately by another section command.