Revised(5) Report on the Algorithmic Language Scheme - Other notations

## 2.3 Other notations

For a description of the notations used for numbers, see section 6.2.

. + -
  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 6.3.2), and to indicate a rest-parameter in a formal parameter list (section 4.1.4). A delimited sequence of three successive periods is also an identifier.
( )
  Parentheses are used for grouping and to notate lists (section 6.3.2).
'
  The single quote character is used to indicate literal data (section 4.1.2).
`
  The backquote character is used to indicate almost-constant data (section 4.2.6).
, ,@
  The character comma and the sequence comma at-sign are used in conjunction with backquote (section 4.2.6).
"
  The double quote character is used to delimit strings (section 6.3.5).
\
  Backslash is used in the syntax for character constants (section 6.3.4) and as an escape character within string constants (section 6.3.5).
[ ] { } |
  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 6.3.1).
  #\
    This introduces a character constant (section 6.3.4).
  #(
    This introduces a vector constant (section 6.3.6). Vector constants are terminated by ")".
  #e #i #b #o #d #x
    These are used in the notation for numbers (section 6.2.4).