Every symbol used in a grammar has to be defined at least once in the
symbol table. Every symbol must be followed by a semicolon:
verb; noun; adjective;
Symbols that are being defined that way are called atoms. A symbol can also be defined as a molecule. Then the entry for this symbol has the following format:
symbol := list;
The list for this symbol must consist of at least two atoms; no atom may
occur more than once in the list. This list will be used by the operators
~ and /~, atoms
, and multi
. The
lists in the symbol table must be different from each other; it does not
suffice that they only differ in the order of their elements. If a symbol is
defined more than once in the symbol table, the definitions must all match:
Either the symbol must always be defined atomic or it must always be molecular
with the same atom-list.