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There are four syntactic forms for atoms.
_
" and alphanumeric characters.
percy_smith_2 semester_1
|-/+*<=>#@$\^&~:.?
For example:
@<=
`
". This form of atom is used when the sequence of characters without the back-quote has been used as the name of a relation, function or action. Such a name cannot be used as an atom unless preceded by a backquote.
`<> `append
'
" (single quote).
Single quote can be included in the sequence by writing the quote twice.
"\
" indicates an escape sequence,
where the escape characters are case insensitive.
The possible escape characters are:
newline | Meaning: Continuation |
^ | Meaning: Same as d . |
^character | Meaning: Control character. |
dd | Meaning: A two digit octal number. |
a | Meaning: Alarm (ASCII = 7 ). |
b | Meaning: Backspace (ASCII = 8 ). |
c | Meaning: Continuation. |
d | Meaning: Delete (ASCII = 127 ). |
e | Meaning: Escape (ASCII = 27 ). |
f | Meaning: Formfeed (ASCII = 12 ). |
n | Meaning: Newline (ASCII = 10 ). |
odd | Meaning: A two digits octal number. |
r | Meaning: Return (ASCII = 13 ) |
s | Meaning: Space (ASCII = 32 ). |
t | Meaning: Horizontal tab (ASCII = 9 ). |
v | Meaning: Vertical tab (ASCII = 11 ). |
xdd | Meaning: A two digit hexadecimal number. |
Here are a few examples of quoted atoms.
'hi!' 'they''re' '\n'
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