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Characters are written using the notation #\character or
#\character-name. For example:
#\a ; lowercase letter #\A ; uppercase letter #\( ; left parenthesis #\space ; the space character #\newline ; the newline character
Case is significant in #\character, but not in
#\character-name. If character in
#\character is a letter, character must be followed
by a delimiter character such as a space or parenthesis. Characters
written in the #\ notation are self-evaluating; you don't need to
quote them.
A character name may include one or more bucky bit prefixes to indicate that the character includes one or more of the keyboard shift keys Control, Meta, Super, Hyper, or Top (note that the Control bucky bit prefix is not the same as the ASCII control key). The bucky bit prefixes and their meanings are as follows (case is not significant):
Key Bucky bit prefix Bucky bit --- ---------------- --------- Meta M- or Meta- 1 Control C- or Control- 2 Super S- or Super- 4 Hyper H- or Hyper- 8 Top T- or Top- 16
For example,
#\c-a ; Control-a #\meta-b ; Meta-b #\c-s-m-h-a ; Control-Meta-Super-Hyper-A
The following character-names are supported, shown here with their ASCII equivalents:
Character Name ASCII Name -------------- ---------- altmode ESC backnext US backspace BS call SUB linefeed LF page FF return CR rubout DEL space tab HT
In addition, #\newline is either #\linefeed or
#\return, depending on the operating system that Scheme is
running under. All of the standard ASCII names for non-printing
characters are supported:
NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US DEL
procedure+: char->name char [slashify?]
Returns a string corresponding to the printed representation of char. This is the character or character-name component of the external representation, combined with the appropriate bucky bit prefixes.
(char->name #\a) => "a" (char->name #\space) => "Space" (char->name #\c-a) => "C-a" (char->name #\control-a) => "C-a"
Slashify?, if specified and true, says to insert the necessary
backslash characters in the result so that read will parse it
correctly. In other words, the following generates the external
representation of char:
(string-append "#\\" (char->name char #t))
If slashify? is not specified, it defaults to #f.
Converts a string that names a character into the character specified.
If string does not name any character, name->char signals
an error.
(name->char "a") => #\a (name->char "space") => #\Space (name->char "c-a") => #\C-a (name->char "control-a") => #\C-a
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