ANSI Common Lisp   2 Syntax   2.4 Standard Macro Characters

2.4.8 Sharpsign

Sharpsign is a non-terminating dispatching macro character. It reads an optional sequence of digits and then one more character, and uses that character to select a function to run as a reader macro function.

The standard syntax includes constructs introduced by the # character. The syntax of these constructs is as follows: a character that identifies the type of construct is followed by arguments in some form. If the character is a letter, its case is not important; #O and #o are considered to be equivalent, for example.

Certain # constructs allow an unsigned decimal number to appear between the # and the character.

The reader macros associated with the dispatching macro character # are described later in this section and summarized in the next figure.

The combinations marked by an asterisk (*) are explicitly reserved to the user. No conforming implementation defines them.

Note also that digits do not appear in the preceding table. This is because the notations #0, #1, ..., #9 are reserved for another purpose which occupies the same syntactic space. When a digit follows a sharpsign, it is not treated as a dispatch character. Instead, an unsigned integer argument is accumulated and passed as an argument to the reader macro for the character that follows the digits. For example, #2A((1 2) (3 4)) is a use of #A with an argument of 2.

2.4.8.1  Sharpsign Backslash
2.4.8.2  Sharpsign Single-Quote
2.4.8.3  Sharpsign Left-Parenthesis
2.4.8.4  Sharpsign Asterisk
2.4.8.5  Sharpsign Colon
2.4.8.6  Sharpsign Dot
2.4.8.7  Sharpsign B
2.4.8.8  Sharpsign O
2.4.8.9  Sharpsign X
2.4.8.10  Sharpsign R
2.4.8.11  Sharpsign C
2.4.8.12  Sharpsign A
2.4.8.13  Sharpsign S
2.4.8.14  Sharpsign P
2.4.8.15  Sharpsign Equal-Sign
2.4.8.16  Sharpsign Sharpsign
2.4.8.17  Sharpsign Plus
2.4.8.18  Sharpsign Minus
2.4.8.19  Sharpsign Vertical-Bar
2.4.8.20  Sharpsign Less-Than-Sign
2.4.8.21  Sharpsign Whitespace
2.4.8.22  Sharpsign Right-Parenthesis