This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
 MessageName symbol :: tag is a name for a message. You can specify messages by defining values for symbol :: tag. symbol :: tag is converted to MessageName[ symbol , " tag "]. tag can contain any characters that can appear in symbol names. symbol ::" tag " can also be used. Assignments for s :: tag are stored in the Messages value of the symbol s. The following messages for functions are often defined: ? f prints out the message f ::usage. When ? form finds more than one function, only the names of each function are printed. You can switch on and off messages using On[ s :: tag ] and Off[ s :: tag ]. MessageName[ symbol , " tag ", " lang "] or symbol :: tag :: lang represents a message in a particular language. See the Mathematica book: Section 2.8.21. See also: Message, MessageList, \$MessageList. Further Examples You can define various tags for functions that you wish to document in some way. Here is a note assigned to the function average. In[1]:= Out[1]= Here is the function definition. In[2]:= You can information about the function average in a variety of ways. In[3]:= Global`average average[list_] := Plus @@ list/Length[list] In[4]:= Out[4]= In[5]:= Out[5]=