What follows is a formal presentation of the syntax of the WikiText syntax for procedure/function/macro calls, using railroad diagrams.

callee-name

• The callee-name is a sequence of non-whitespace characters other than ( or >.
• whitespace denotes a sequence of whitespace characters.

param-value

Each individual param-value has the following syntax:

• The param-name is a sequence of letters (A–Z, a–z), digits (0–9), hyphens (-) and underscores (_).
• The value is specified as follows:

• New in v5.4.0 The new-value can either be a plain value or a full callee-name call, allowing for dynamic parameter values.