symbol.text

Portable Lisp symbol syntax

Punctuation permitted in symbols

!   suffix for destructive operators (Scheme, Clojure)
$   no particular meaning
&   prefix for lambda list keywords (Common Lisp)
*   prefix and suffix for dynamic variables (Common Lisp); math operator
+   prefix and suffix for constants (Common Lisp); math operator
-   word delimiter in multi-word symbols; math operator
/   math operator
<   math operator
=   math operator
>   math operator
_   word delimiter in multi-word symbols (occasionally)

Punctuation permitted in symbols, but not as the first character

.   consing dot; prefix for instance method call (Clojure)
?   prefix for character literal (Emacs Lisp); suffix for predicate (Scheme, Clojure)
@   prefix for splice operation (Kawa Scheme)

Punctuation permitted in symbols, but only as the first character:

:   prefix for keyword (CL, some Schemes);
    disallowed as infix for symbol package (Common Lisp);
    symbols beginning with more than one : are disallowed

Punctuation not allowed anywhere in a symbol

#   prefix for syntax extension; comment (Janet)
%   prefix for character literal (Interlisp)
'   prefix for quote
,   prefix for unquote
;   prefix for comment
\   prefix for character literal (Clojure); infix for string escape
^   prefix for metadata attached to an object (Clojure)
`   prefix for backquote/quasiquote
~   prefix for unquote (Clojure)

Punctuation not allowed anywhere in a symbol (paired)

""  string literal
()  paired delimiters
[]  paired delimiters (Clojure, Scheme)
{}  maps and sets (Clojure)
||  symbol written using string syntax (Common Lisp, Scheme)