1 Introduction 1.4 Definitions 1.4.4 Interpreting Dictionary Entries 220.127.116.11 The "Syntax" Section of a Dictionary Entry
18.104.22.168.1 Special "Syntax" Notations for Overloaded OperatorsIf two descriptions exist for the same operation but with different numbers of arguments, then the extra arguments are to be treated as optional. For example, this pair of lines:
file-position stream position
file-position stream position-spec success-p
is operationally equivalent to this line:
file-position stream &optional position-spec result
and differs only in that it provides on opportunity to introduce different names for parameter and values for each case. The separated (multi-line) notation is used when an operator is overloaded in such a way that the parameters are used in different ways depending on how many arguments are supplied (e.g., for the function /) or the return values are different in the two cases (e.g., for the function file-position).