clojuria |clo juːrɪa|
noun
Ultimate state of a blissful mind for any clojurian, achieved when all concurrent thoughts truly align and incidental complexity reaches zero - for always one abstraction away.
DERIVATIVES
clojurian noun
Tales from the REPL - Therapeutic, after-hours ramblings of a lazy Clojurian
Friday, March 16, 2012
Wednesday, February 1, 2012
Clojurian
clojurian |clo juːrɪən|
noun
A coding practitioner seeking enlightenment thru persistent parens abstractions, immutable state identities, incidental functional laziness and a virtual hammock.
DERIVATIVES
clojurinian adverb
ORIGIN early 21th cent.:... sounds like zen... must be good...
cljsh & repls - so many repls, so little time...
"repls" is a persistent clojure repl-server, while "cljsh" is the associated client that sends the clojure code that is passed as command line arguments and/or as a clj-files to that repl-server for evaluation. The code and detailed installation instructions can be found on github: https://github.com/franks42/lein-repls.
Hello World in many flavors and name spaces.
The next session shows a different terminal session from the one where the repl-server was started. Note that you have to start the cljsh-repls interaction from within the same project directory where you started the server. The reason is that the repl-server recorded the port-number on which it listens in the project's home directory (.lein_repls), and cljsh will use that info to connect to the right server.
As you see, clj-code can be submitted as option values on the command line, and -c and -e are equivalent (cljsh -h will give you a list of all the option). Furthermore, the default namespace seems to be "user" as expected.
Notice that the namespace set in a cljsh invocation is not persistent across invocations - each invocation starts at the default ns. Newly created vars and functions are persistent, however, and can be used across invocations.
Eval results and errors.
The evaluation results are discarded by default. The -p option turns the printing of eval results on. Notice also that any errors that are reported in stack traces and such, are shown on the console:
Error is shown on console:
The many ways to skin the script.
Clojure code can be passed as statements or as files in a number of different ways:
cljsh processes the code specified by the options in sequence. Note that the input from stdin is last by default and can optionally be indicated with "-".
Note that all the code submitted with one cljsh invocation is evaluated within the same context: changing the ns in the first statement has effect for all subsequent statements within that one invocation.
One other option is to create executable "#!" clojure-shell script files, like:
which also show that cljsh passed the additional arguments in the var "cljsh.core/*cljsh-command-line-args*".
The following last example show that the -t flag allows you to pass arbitrary data thru stdin, which you can then process with you clojure scripts. Unix-style filters can be written that way:
Well, enough for this first cljsh blog... the plan is to show how to use cljsh with labrepl, growl and macosx-automation next time.
With a number of annotated command line sessions, I wanted to illustrate some of the features of cljsh and repls. The first thing you have to do is start a new project with lein, and for this example, that's all we need to do:
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| ~/tmp>lein new cljsh-test | |
| Created new project in: /Users/franks/tmp/cljsh-test | |
| Look over project.clj and start coding in cljsh_test/core.clj | |
| ~/tmp>cd cljsh-test/ | |
| ~/tmp/cljsh-test>lein repls | |
| Copying 1 file to /Users/franks/tmp/cljsh-test/lib | |
| ## Clojure 1.3.0 - "lein-repls" console and server started on project "cljsh-test 1.0.0-SNAPSHOT" (pid/host/port:42914/localhost/30927) ## | |
| user=> |
We created a new "cljsh-test" project, and started the repl-server inside of the project directory tree with "lein repls". Besides the repl-server, it also started an interactive java-based repl-client. We will not use this repl-client at all, but you should consider it like a "console" as it will show the error messages and stack traces if anything goes wrong with the submitted code by cljsh. Note that the repl-prompt shows the "user" namespace as the default, which will be the starting point for all cljsh invocation.
Hello World in many flavors and name spaces.
The next session shows a different terminal session from the one where the repl-server was started. Note that you have to start the cljsh-repls interaction from within the same project directory where you started the server. The reason is that the repl-server recorded the port-number on which it listens in the project's home directory (.lein_repls), and cljsh will use that info to connect to the right server.
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| ~/tmp>cd cljsh-test/ | |
| ~/tmp/cljsh-test>cat .lein_repls | |
| export LEIN_REPL_PORT=30927 | |
| export LEIN_REPL_PID=42907 | |
| ~/tmp/cljsh-test>cljsh -c '(println "Bye World")' -e '(println "Thanks for all the fish")' | |
| Bye World | |
| Thanks for all the fish | |
| ~/tmp/cljsh-test>cljsh -c '(println "the current ns is:" *ns*)' | |
| the current ns is: #<Namespace user> | |
| ~/tmp/cljsh-test> |
As you see, clj-code can be submitted as option values on the command line, and -c and -e are equivalent (cljsh -h will give you a list of all the option). Furthermore, the default namespace seems to be "user" as expected.
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| ~/tmp/cljsh-test>cljsh -c '(defn p*ns* [] (println "ns:" *ns*))' | |
| ~/tmp/cljsh-test>cljsh -c '(p*ns*)' | |
| ns: #<Namespace user> | |
| ~/tmp/cljsh-test>cljsh -c '(ns newuser)' -c '(user/p*ns*)' | |
| ns: #<Namespace newuser> | |
| ~/tmp/cljsh-test>cljsh -c '(user/p*ns*)' | |
| ns: #<Namespace user> | |
| ~/tmp/cljsh-test> |
Notice that the namespace set in a cljsh invocation is not persistent across invocations - each invocation starts at the default ns. Newly created vars and functions are persistent, however, and can be used across invocations.
Eval results and errors.
The evaluation results are discarded by default. The -p option turns the printing of eval results on. Notice also that any errors that are reported in stack traces and such, are shown on the console:
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| ~/tmp/cljsh-test>cljsh -c '"you cannot see me"' | |
| ~/tmp/cljsh-test>cljsh -p -c '"but now you can"' | |
| "but now you can" | |
| ~/tmp/cljsh-test>cljsh -c '(printlnn "one n too many")' |
Error is shown on console:
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| ## Clojure 1.3.0 - "lein-repls" console and server started on project "cljsh-test 1.0.0-SNAPSHOT" (pid/host/port:42914/localhost/30927) ## | |
| user=> | |
| CompilerException java.lang.RuntimeException: Unable to resolve symbol: printlnn in this context, compiling:(/var/folders/th/v9cn0zjn1830736cjqg8l9jm0000gn/T/cljsh.auwi2qgL:1) |
The many ways to skin the script.
Clojure code can be passed as statements or as files in a number of different ways:
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| ~/tmp/cljsh-test>echo '(println "one")' > one.clj | |
| ~/tmp/cljsh-test>echo '(println "two")' > two.clj | |
| ~/tmp/cljsh-test>echo '(println "three")' > three.clj | |
| ~/tmp/cljsh-test>echo '(println "four")' > four.clj | |
| ~/tmp/cljsh-test>cat three.clj | cljsh -c '(println "one")' -f two.clj - four.clj | |
| one | |
| two | |
| three | |
| four | |
| ~/tmp/cljsh-test> |
cljsh processes the code specified by the options in sequence. Note that the input from stdin is last by default and can optionally be indicated with "-".
Note that all the code submitted with one cljsh invocation is evaluated within the same context: changing the ns in the first statement has effect for all subsequent statements within that one invocation.
One other option is to create executable "#!" clojure-shell script files, like:
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| ~/tmp/cljsh-test>cat > tst.cljsh <<-EOF | |
| > #!/usr/bin/env cljsh | |
| > (println "wow") | |
| > (println "args are:" cljsh.core/*cljsh-command-line-args*) | |
| > EOF | |
| ~/tmp/cljsh-test>chmod +x tst.cljsh | |
| ~/tmp/cljsh-test>./tst.cljsh -all -my args | |
| wow | |
| args are: -all -my args | |
| ~/tmp/cljsh-test> |
which also show that cljsh passed the additional arguments in the var "cljsh.core/*cljsh-command-line-args*".
The following last example show that the -t flag allows you to pass arbitrary data thru stdin, which you can then process with you clojure scripts. Unix-style filters can be written that way:
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| ~/tmp/cljsh-test>cat <<"EOCLJ" > upper.cljsh | |
| > #!/usr/bin/env cljsh -t | |
| > (require 'clojure.string) | |
| > (doseq [line (line-seq (java.io.BufferedReader. *in*))] | |
| > (prn (clojure.string/upper-case line))) | |
| > (.close *in*) | |
| > EOCLJ | |
| ~/tmp/cljsh-test>chmod +x upper.cljsh | |
| ~/tmp/cljsh-test>echo "down2up2down" | ./upper.cljsh | |
| "DOWN2UP2DOWN" | |
| ~/tmp/cljsh-test>echo "down2up2down" | ./upper.cljsh | tr '[:upper:]' '[:lower:]' | |
| "down2up2down" | |
| ~/tmp/cljsh-test> |
Well, enough for this first cljsh blog... the plan is to show how to use cljsh with labrepl, growl and macosx-automation next time.
Tuesday, January 31, 2012
Clojuresque
clojuresque |clo ju əˈresk|
adjective
visually attractive, esp. in a quaint or pretty style, idiomatic, clojure code.
DERIVATIVES
clojuresquely adverb
clojuresqueness noun
ORIGIN early 21th cent.:... sounds French and sexy...
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