cl-format is too slow for production use

Description

Run this example code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(in-ns 'clojure.pprint)

(println "Basic output using raw str.")
(time
(doseq [i (range 1000)]
(apply str (interpose "," [1 2 3]))))

(println "Test 1 - raw cl-format")
(time
(doseq [i (range 1000)]
(clojure.pprint/cl-format nil "{~D^,~}" [1 2 3])))
;; ==> "Elapsed time: 231.345 msecs"

(println "Test 2 - call on the compiled format")
(def myx
(compile-format "{~D^,~}"))

(time
(doseq [i (range 1000)]
(clojure.pprint/cl-format nil myx [1 2 3])))

(println "Test 3 - using a formatter")
(def myy
(formatter "{~D^,~}"))

(time
(doseq [i (range 1000)]
(myy nil myx [1 2 3])))

(time
(dotimes (i 100000)
(format nil "{~D^,~}" '(1 2 3))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

It will print something like this:

Basic output using raw str.
"Elapsed time: 2.402 msecs"
Test 1 - raw cl-format
"Elapsed time: 194.405 msecs"
Test 2 - call on the compiled format
"Elapsed time: 87.271 msecs"
Test 3 - using a formatter
"Elapsed time: 199.318 msecs"

So raw `str' is ~ 100X faster.

For reference, on the same hardware, using
SBCL Common Lisp, this test runs in < 1 ms.

There are (at least) 2 problems here:

1. cl-format function begins with a line like:

let [compiled-format (if (string? format-in) (compile-format format-in) format-in)

But there is no api to pass in a compiled-format into it; (as compile-format
is a private function, so can't be used at large) so this is kind of useless.

2. Even using a precompiled formatter is way too slow.

Suggested fix: none, except perhaps warning unwary users that this
function is simply not suitable for tight loops, and should only be
used to pretty print user input strings, etc.

Thank you

Environment

Mac OS X - 3GHz i7 16Gb ram

Status

Assignee

Unassigned

Reporter

import

Labels

Approval

Triaged

Patch

None

Affects versions

Release 1.9
Release 1.7

Priority

Minor