(EXT:ETHE value-type form) enforces a type check in both interpreted and compiled code.

These macros are similar to LET and LET*, respectively, except that they can bind places, even places with multiple values. Example:

(letf (((values a b) form)) ...)

is equivalent to

(multiple-value-bind (a b) form ...)

while

(letf (((first l) 7)) ...)

is approximately equivalent to

 (LET* ((#:g1 l) (#:g2 (first #:g1)))
   (UNWIND-PROTECT (PROGN (SETF (first #:g1) 7) ...)
      (SETF (first #:g1) #:g2)))

(EXT:MEMOIZED form) memoizes the primary value of form from its first evaluation.

Similar to the LOOP's collect construct, except that it is looks more "Lispy" and can appear arbitrarily deep. It defines local macros (with MACROLET) which collect objects given to it into lists, which are then returned as multiple values. E.g.,

(ext:with-collect (c0 c1)
  (dotimes (i 10) (if (oddp i) (c0 i) (c1 i))))
⇒ (1 3 5 7 9) ;
⇒ (0 2 4 6 8)

returns two LISTs (1 3 5 7 9) and (0 2 4 6 8) as multiple values.

Similar to its namesake from Paul Graham's book “On Lisp”, this macro is useful for writing other macros:

(with-gensyms ("FOO-" bar baz zot) ...)

expands to

(let ((bar (gensym "FOO-BAR-"))
      (baz (gensym "FOO-BAZ-"))
      (zot (gensym "FOO-ZOT-")))
  ...)

Similar to REMOVE and REMF, this function removes some properties from a property list. It is non-destructive and thus can be used on &REST arguments to remove some keyword parameters, e.g.,

(defmacro with-foo ((&KEY foo1 foo2) &BODY body)
  `(... ,foo1 ... ,foo2 ... ,@body))
(defmacro with-foo-bar ((&REST opts &KEY bar1 bar2
                         &ALLOW-OTHER-KEYS)
                        &BODY body)
  `(with-foo (,@(remove-plist opts :bar1 :bar2)
     ... ,bar1 ... ,bar2 ... ,@body)))
(defun foo-bar ()
  (with-foo-bar (:bar1 1 :foo2 2) ...))

here WITH-FOO does not receive the :BAR1 1 argument from FOO-BAR.

Defined in inspect.lisp, these macros are useful for the rudimentary HTTP server defined there.

Defined in clhs.lisp, they allow downloading data over the Internet using the HTTP protocol. (EXT:OPEN-HTTP url &KEY :IF-DOES-NOT-EXIST) opens a socket connection to the url host, sends the GET request, and returns two values: the SOCKET:SOCKET-STREAM and content length. (EXT:WITH-HTTP-INPUT (variable url) &BODY body) binds variable to the SOCKET:SOCKET-STREAM returned by EXT:OPEN-HTTP and executes the body. (EXT:WITH-HTTP-INPUT ((variable contents) url) &BODY body) additionally binds contents to the content length.

EXT:OPEN-HTTP will check CUSTOM:*HTTP-PROXY* on startup and parse the environment variable HTTP_PROXY if CUSTOM:*HTTP-PROXY* is NIL.

Function (EXT:BROWSE-URL url &KEY :BROWSER :OUT) calls a browser on the URL. browser (defaults to CUSTOM:*BROWSER*) should be a valid keyword in the CUSTOM:*BROWSERS* association list. :OUT specifies the stream where the progress messages are printed (defaults to *STANDARD-OUTPUT*).

If you are behind a proxy server, you will need to set CUSTOM:*HTTP-PROXY* to a LIST (name:password host port). By default, the environment variable http_proxy is used, the expected format is "name:password@host:port". If no #\@ is present, name and password are NIL. If no #\: is present, password (or port) are NIL.

Use function (EXT:HTTP-PROXY &OPTIONAL (STRING (EXT:GETENV "http_proxy"))) to reset CUSTOM:*HTTP-PROXY*.