jafingerhut’s gists

jafingerhut / apropos2.clj

Created February 7, 2012 05:27

apropos2 and unresolve

	;; Example use of unresolve:

	;; user=> (unresolve #'replace)
	;; (replace clojure.core/replace)
	;; user=> (use 'clojure.string)
	;; WARNING: replace already refers to: #'clojure.core/replace in namespace: user, being replaced by: #'clojure.string/replace
	;; WARNING: reverse already refers to: #'clojure.core/reverse in namespace: user, being replaced by: #'clojure.string/reverse
	;; nil
	;; user=> (unresolve #'replace)
	;; (replace clojure.string/replace)

jafingerhut / foo.java

Created November 9, 2012 16:40

AndroChef Java decompiler output of class file compiled from Cedric Greevey's Clojure code

	package perf;

	import clojure.lang.AFunction;
	import clojure.lang.IFn;
	import clojure.lang.Indexed;
	import clojure.lang.Numbers;
	import clojure.lang.RT;
	import clojure.lang.Var;
	import java.awt.image.BufferedImage;
	import perf.core.foo.fn__14;

jafingerhut / str-seq-reader.clj

Last active December 31, 2015 17:19

str-seq-reader - Take a sequence of strings and return a Java Reader that, when read, returns the contents of the concatenation of those strings. Only as much of the sequence as needed by the reader is consumed. Examples of use at the bottom.

	(ns piper.core
	(:require [clojure.java.io :as io]
	[clojure.string :as str])
	(:import (java.io Reader Writer BufferedReader)))

	(defn str-seq-reader
	"Return a java.io.Reader that returns the same sequence of
	characters as are in the concatenation of the sequence of strings
	given as an argument. Consumes only as much of the sequence as needed
	for any given read operation."

jafingerhut / gist:8359201

Last active January 2, 2016 20:49

do's inside top level do's are 'flattened'

	;; In a fresh Clojure 1.5.1 'lein repl'

	;; clojure.edn is not loaded yet
	user=> (clojure.edn/read-string "(5)")

	ClassNotFoundException clojure.edn java.net.URLClassLoader$1.run (URLClassLoader.java:366)

	;; trying to eval this form does not do it, because it fails to analyze as a whole
	user=> (eval `(when true (require 'clojure.edn) (clojure.edn/read-string "(5)")))

jafingerhut / pprint-metadata-weirdness.clj

Last active August 29, 2015 14:02

	;; Examples showing that when print-meta is bound to true, clojure.pprint/pprint appears
	;; to show metadata on symbols, but not on collections. Can be misleading when only some
	;; metadata is shown. Led me to believe the other metadata wasn't there until I double-checked
	;; with pr.

	(defn ppm [f m]
	(binding [print-meta m]
	(clojure.pprint/pprint f)))

	(defn prm [f m]

jafingerhut / inputstream.clj

Created July 8, 2014 15:01

Example of reading java.io.InputStream in Clojure

	(ns inputstream.core
	(:require [clojure.java.io :as io]))


	(defn read-is [^java.io.InputStream is]
	(let [bufsize 8192
	buf (byte-array bufsize)]
	(loop [total-len 0]
	(let [n (.read is buf)]
	(cond

jafingerhut / tag-vars.clj

Created September 24, 2014 17:33

	;; TBD: What is going on here?

	;; Why does (Math/abs (f2 -3)) cause a
	;; reflection warning, but neither of the other variants does?

	user=> (clojure-version)
	"1.6.0"
	user=> (set! warn-on-reflection true)
	true
	user=> (defn ^{:tag 'long} f1 [x] (inc x))

jafingerhut / reify-ns-qualified-args.clj

Created November 4, 2014 23:09

Reify with namespace-qualified args

	user=> (def b 7)
	#'user/b
	user=> (def fplus2 (reify java.lang.Object (hashCode [user/b] (+ user/b 2))))
	#'user/fplus2
	user=> (.hashCode fplus2)
	9

jafingerhut / macrometa.clj

Last active August 29, 2015 14:09

Clojure metadata lost during macro invocations

	;; Clojure JIRA ticket CLJ-865: http://dev.clojure.org/jira/browse/CLJ-865
	;; was created with the intent of changing some of the behavior below, but it is
	;; not clear as of late 2014 whether the behavior is considered a bug that should
	;; be changed.

	;; Nicola Mometto pointed out that there may be similar issues with metadata
	;; being eliminated for primInvoke's and functions defined with definline.
	;; Perhaps http://dev.clojure.org/jira/browse/CLJ-1533 is related.

	user=> clojure-version

jafingerhut / merge-sorted-seqs.clj

Created April 5, 2015 01:36

merge-sorted-seqs.clj

	;; Example:
	;; (merge-sorted-seqs < (range 10 1000 3) (range 12 1000 5))

	(defn merge-sorted-seqs [cmpf seq1 seq2]
	(let [seq1wins (and (seq seq1)
	(or (nil? (seq seq2))
	(cmpf (first seq1) (first seq2))))]
	(if seq1wins
	(lazy-seq (cons (first seq1)
	(merge-sorted-seqs cmpf (next seq1) seq2)))

Andy Fingerhut jafingerhut