Rules for Presenting and Using Syntax Graphs

The rules for syntax graphs are as follows:

1. Each graph represents a command (or part of a command) to AVEVA E3D Design to perform specified actions with specified data. The graph is entered at "graph_name>--" or ">--", and exited at "-->". The allowed flow in a graph is top to bottom, and left to right, except where indicated otherwise by a "*" or "<" symbol.

2. Vertical lines with one or more "+" symbols represent a new state. These are always traversed downwards. There should be a "+" for each allowable entry point into a state. The "+" symbols can only be traversed from left to right.

3. Horizontals to the right of state lines, represent command words and data which are allowable in the state. They can only be traversed from left to right.

   1. Words starting with capitals represent command words. The capitalized part represents the minimum syntax which is recognized. Lower case parts denote optional characters. The whole thing is actually case independent as far as you are concerned.

   2. Words enclosed in "< >" represent a call to the named graph. These should be lower case. Graph calls can be recursive.

   3. Words in lower case only, represent ‘notionally’ atomic data items, e.g. text, integer, val (numeric value). Sometimes they are in fact graph calls, for example, ‘fname’ and ‘gname’. Sometimes they are fictitious, for example, ‘tagtext’, but more helpful than just "text" and easier to understand than a reference to, say, <fgtag>.

4. Continuous vertical and horizontal lines without a " + " symbol represent flow lines of the graph.

   4. The presence of a "*" symbol in a vertical line indicates that the allowed direction of traverse is upwards.

   5. The presence of a "<" symbol on a horizontal indicates that the allowed direction of traverse is backwards.

   6. The symbols " . ", " / ", " ‘ " are just cosmetic to help the graph to look better.