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2.3 Other notations

For a description of the notations used for numbers, see section Numbers.

. + -

These are used in numbers, and may also occur anywhere in an identifier except as the first character. A delimited plus or minus sign by itself is also an identifier. A delimited period (not occurring within a number or identifier) is used in the notation for pairs (section see Pairs and lists), and to indicate a rest-parameter in a formal parameter list (section see Procedures). A delimited sequence of three successive periods is also an identifier.

( )

Parentheses are used for grouping and to notate lists (section see Pairs and lists).


The single quote character is used to indicate literal data (section see Literal expressions).


The backquote character is used to indicate almost-constant data (section see Quasiquotation).

, ,@

The character comma and the sequence comma at-sign are used in conjunction with backquote (section see Quasiquotation).


The double quote character is used to delimit strings (section see Strings).


Backslash is used in the syntax for character constants (section see Characters) and as an escape character within string constants (section see Strings).

[ ] { } |

Left and right square brackets and curly braces and vertical bar are reserved for possible future extensions to the language.


Sharp sign is used for a variety of purposes depending on the character that immediately follows it:

#t #f

These are the boolean constants (section see Booleans).


This introduces a character constant (section see Characters).


This introduces a vector constant (section see Vectors). Vector constants are terminated by ) .

#e #i #b #o #d #x

These are used in the notation for numbers (section see Syntax of numerical constants).

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