pTAL Reference Manual (G06.24+, H06.09+, J06.03+)

To use a railroad diagram, follow the direction of the arrows and specify syntactic items as indicated
by the diagram pieces:
MeaningDiagram Piece
Type KEYWORD as shown. You can type letters in
uppercase or lowercase.
Replace item with a value that fits its description, which
follows the syntax diagram.
Type content (punctuation mark, symbol, or letter) as shown.
You can type a letter in uppercase or lowercase.
Some examples of the meanings of simple diagrams are:
MeaningDiagram Piece
Choose item1 or item2.
Choose item1, item2, or neither.
Specify item one or more times, separating occurrences
with commas.
Specify item at most n times.
NOTE: To refer to a particular railroad diagram or figure when giving feedback to HP, use the
number at the bottom right corner of that railroad diagram or figure (for example, VST742.vsd).
Spacing rules are:
• If the arrow between two diagram pieces is labelled “ns,” put no spaces between the syntactic
items that they represent. For example:
Notation Conventions 21