Macro Characters
Macro characters used by various libraries: (TOTALLY INCOMPLETE AND OUTDATED)

direct character definition

Char Meaning Used by
λ (lambda) LAMBDA lambda-reader
Λ (Lambda) LAMBDA lambda-reader
@ Timestring local-time
[ Markup Scribble

# dispatch

(Note that the subchar dispatching is done case insensitively, so we list only uppercase letters, but the corresponding lower case letter may be used too (and might be used often for better readability, notably when a numerical argument is present before and after the subchar)).

Char Meaning Used by
I Infix syntax Infix
? String interpolation cl-interpol
` (backquote) Shell command output substitution clawk
/ Regular expression symbol clawk
U URLs CL-HTTP Puri uri-template cl-uri-templates
_ (underscore) FFI Traps CCL
_ (underscore) A lookup for Qt functionality CommonQt
$ FFI Constants CCL
! Unix shell scripting (known as "shebang") CLISP and others
@ read-time splicing cl-rttemplate
" (double quote) a read-time quasiquote cl-rttemplate
" (double quote) pathnames (predates #P?) CLISP
L Lambda: #L(list* !1 '- !2) as shorthand for two-arg LAMBDA iterate
M Money: #978m123.43 = 123.43 EUR ; #840m123.43 = 123.43 USD in com.informatimago.common-lisp.invoice (should be extracted as a stand-alone library, bug Pascal Bourguignon)
N Infix syntax mexpr

programming tips