- someone's definition of "legacy code" includes something you wrote
- you know what "load *,8,1" means
- you remember when we used to call them "scripting languages"
- you simply can't continue to code after 2:30 AM
- you had a BBS handle
- this means something to you: "Hello everybody out there using minix -"
- these screens ring a bell? : http://toastytech.com/guis/guitimeline.html
Showing posts with label dynlang. Show all posts
Showing posts with label dynlang. Show all posts
Wednesday, December 12, 2007
You know you are getting old when
Just a few things that make me feel old sometimes... what does the same for you?
Sunday, November 25, 2007
Simple file IO in different dynamic languages
Was just messing around and thought I would look at the different ways to skin a cat... in this case, the cat being "read each line of a file and spit out it's contents". I'm using TCL, Python, PHP, Ruby, Groovy, Scala and Javascript (Rhino) for this example. Let's take a look at what I came up with:
[sourcecode language="css"]
set fp [open "test.txt" r]
while {[gets $fp line] != -1} {
puts stdout $line
}
close $fp[/sourcecode]
Here we need to open the file pointer and loop over the file using a procedure call to 'gets' which sets a local variable 'line' for us. ('gets' is wrapped in brackets so we can validate on it's return, the length of the string returned by gets proc call.) Finally we will need to close our file pointer.
[sourcecode language="python"]
f = open("test.txt")
try:
for line in f:
print line.strip()
finally:
f.close()[/sourcecode]
Similar to TCL, we are getting our file pointer (in this case an object), looping the file object and closing the pointer. Version 2.6 will support the 'with' keyword allowing you to wrap the file IO in a block (therefor closing the file pointer for you after executing the block.) Here's what it will look like:
[sourcecode language="python"]
from __future__ import with_statement # <-- only use this line for Python 2.5!
with open("test.txt") as f:
for line in f:
print line.strip()[/sourcecode]
[sourcecode language="php"]
foreach (file('test.txt') as $line) {
echo $line;
}[/sourcecode]
This code looks 'blockish', but we're actually calling a function 'file' which returns the file's contents as an array... the file pointer is created and closed within this function so we don't have to worry about closing it in this example.
[sourcecode language="ruby"]
# File.open('test.txt', 'r').each do |line| <-- BAD: open file pointer
File.foreach('test.txt', 'r') do |line| <-- CORRECTION
puts line
end[/sourcecode]
UPDATE: was leaving file pointer open... thanks for the correction Sebastian Hungerecker.
Now we are getting OO with blocks. We're creating a File object and calling that object's 'each' method which iterates over each line of the file and passes the contents to the supplied block.
[sourcecode language="java"]
new File("test.txt").eachLine { line ->
println line
}[/sourcecode]
Again, OO with blocks... very similar to Ruby.
[sourcecode language="css"]
import scala.io.Source
for {
(line) <- Source.fromFile("test.txt").getLines
} print(line)[/sourcecode]
Procedural type programming using a language that 'goes both ways.' Similar to the PHP code above, the file IO is wrapped up in the 'Source.fromFile' method call which returns a 'Source' object already populated with the file's contents. We then call the getLines method which returns an iterable collection.
[sourcecode language="javascript"]
lines = readFile("test.txt").split("\n");
lines.pop(); // <-- last item is empty... EOF?
for (i in lines) {
print(lines[i]);
}[/sourcecode]
Using a Rhino built-in 'readFile' to get the contents of the file, splitting on line breaks using OO method call, and finally looping the array and printing it's contents. You see something I had to do here to get rid of the empty item in 'lines'.
Update: I failed to mention, these times include JVM startup so it's not a true speed check for IO... rather from the command line experience (total execution time of one call.) This can paint a bad light on the JVM impls, but keep in mind the JVM is built for long running rather than one shot processes.
Of course I was curious... what kind of speed do these languages have for this basic IO? The test file contained only the following:
I don't have the latest and greatest for a few of these... but here are the versions and real time taken. (using 'time' on Mac OS X 10.4.10)
[sourcecode language="css"]
RUBY: 0m0.009s (1.8.6)
TCL: 0m0.012s (8.5)
PHP: 0m0.024s (4.4.7)
Python: 0m0.034s (2.5.1)[/sourcecode]
[sourcecode language="css"]
RHINO: 0m0.310s (1.6R2)
GROOVY: 0m0.885s (1.0)
SCALA: 0m1.312s (2.6.0)
JRUBY: 0m1.668s (1.1b1)[/sourcecode]What does all of this mean? Not much really... just that there are a lot of different ways (many of which I didn't cover here) to skin a cat. Just choose the one that fits your needs and have fun with it.
Did I miss your favorite language here? Did I not use the most optimal code for accomplishing this task? Let me know!
Code
TCL
[sourcecode language="css"]
set fp [open "test.txt" r]
while {[gets $fp line] != -1} {
puts stdout $line
}
close $fp[/sourcecode]
Here we need to open the file pointer and loop over the file using a procedure call to 'gets' which sets a local variable 'line' for us. ('gets' is wrapped in brackets so we can validate on it's return, the length of the string returned by gets proc call.) Finally we will need to close our file pointer.
Python
[sourcecode language="python"]
f = open("test.txt")
try:
for line in f:
print line.strip()
finally:
f.close()[/sourcecode]
Similar to TCL, we are getting our file pointer (in this case an object), looping the file object and closing the pointer. Version 2.6 will support the 'with' keyword allowing you to wrap the file IO in a block (therefor closing the file pointer for you after executing the block.) Here's what it will look like:
[sourcecode language="python"]
from __future__ import with_statement # <-- only use this line for Python 2.5!
with open("test.txt") as f:
for line in f:
print line.strip()[/sourcecode]
PHP
[sourcecode language="php"]
foreach (file('test.txt') as $line) {
echo $line;
}[/sourcecode]
This code looks 'blockish', but we're actually calling a function 'file' which returns the file's contents as an array... the file pointer is created and closed within this function so we don't have to worry about closing it in this example.
Ruby
[sourcecode language="ruby"]
# File.open('test.txt', 'r').each do |line| <-- BAD: open file pointer
File.foreach('test.txt', 'r') do |line| <-- CORRECTION
puts line
end[/sourcecode]
UPDATE: was leaving file pointer open... thanks for the correction Sebastian Hungerecker.
Now we are getting OO with blocks. We're creating a File object and calling that object's 'each' method which iterates over each line of the file and passes the contents to the supplied block.
Groovy
[sourcecode language="java"]
new File("test.txt").eachLine { line ->
println line
}[/sourcecode]
Again, OO with blocks... very similar to Ruby.
Scala
[sourcecode language="css"]
import scala.io.Source
for {
(line) <- Source.fromFile("test.txt").getLines
} print(line)[/sourcecode]
Procedural type programming using a language that 'goes both ways.' Similar to the PHP code above, the file IO is wrapped up in the 'Source.fromFile' method call which returns a 'Source' object already populated with the file's contents. We then call the getLines method which returns an iterable collection.
Javascript (Mozilla Rhino)
[sourcecode language="javascript"]
lines = readFile("test.txt").split("\n");
lines.pop(); // <-- last item is empty... EOF?
for (i in lines) {
print(lines[i]);
}[/sourcecode]
Using a Rhino built-in 'readFile' to get the contents of the file, splitting on line breaks using OO method call, and finally looping the array and printing it's contents. You see something I had to do here to get rid of the empty item in 'lines'.
Speed?
Update: I failed to mention, these times include JVM startup so it's not a true speed check for IO... rather from the command line experience (total execution time of one call.) This can paint a bad light on the JVM impls, but keep in mind the JVM is built for long running rather than one shot processes.
Of course I was curious... what kind of speed do these languages have for this basic IO? The test file contained only the following:
this
is
a
test
I don't have the latest and greatest for a few of these... but here are the versions and real time taken. (using 'time' on Mac OS X 10.4.10)
Native Impls
[sourcecode language="css"]
RUBY: 0m0.009s (1.8.6)
TCL: 0m0.012s (8.5)
PHP: 0m0.024s (4.4.7)
Python: 0m0.034s (2.5.1)[/sourcecode]
JVM Impls
[sourcecode language="css"]
RHINO: 0m0.310s (1.6R2)
GROOVY: 0m0.885s (1.0)
SCALA: 0m1.312s (2.6.0)
JRUBY: 0m1.668s (1.1b1)[/sourcecode]What does all of this mean? Not much really... just that there are a lot of different ways (many of which I didn't cover here) to skin a cat. Just choose the one that fits your needs and have fun with it.
Did I miss your favorite language here? Did I not use the most optimal code for accomplishing this task? Let me know!
Tuesday, October 30, 2007
“DynLangs” and you…
Unless you have been living behind your monitor and keyboard only to look up to find the coffee mug you knocked over, you've most likely heard about all the attention dynamic languages, or dynlangs, have been getting these days. Dynamic Languages (or scripting languages) have been taking their spot in the limelight in recent years... I feel this is in large part due to the readily available video streaming sites showcasing the benefits of such languages/frameworks.
For those willing to step outside the compiler, large gains in productivity abound. And with so many dynamic language options being implemented on the JVM, JSR 223, and attention from large companies... dynlangs are quickly becoming viable options in companies and organizations that would never have considered using them in the past.
If you primarily work with a compiled language (Java maybe?) and don't want to miss the productivity boat, you may want to review the following list comprised of just a few languages/frameworks making waves (on and off the JVM) :
Languages
Ruby
Object Oriented, interpreted, dynamically typed language. Created by Yukihiro “matz” Matsumoto, everything is an object and every class is "open" for change.
JRuby
JVM implementation of the Ruby language... provides the ability to use the Ruby language and leverage the existing capabilities of the Java Virtual Machine (and all it's libraries.)
Groovy
Dynamic OO language built for the JVM... "builds upon the strengths of Java but has additional power features inspired by languages like Python, Ruby and Smalltalk"
Python
Dynamic OO language, embeddable, integration friendly, dynamically typed. Strong user base.
Jython
JVM implementation of the Python language... project has fallen behind the Python pace, but new life buds. As with most JVM dynlangs, Jython provides Java integration.
Scala
Type-safe, both object oriented and functional. Written for the JVM so the Java integration is there.
Rhino
JVM implementation of the JavaScript language... all you would by now expect from a JVM dynlang, Java integration, embeddable, shell access.
... and of course...
PHP
"PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML." Heavily pervasive, low barrier to entry, object oriented with PHP 5, large library code base.
(PHP can now run on the JVM too: Quercus)
Web Frameworks
Ruby on Rails
"Rails is a full-stack framework for developing database-backed web applications according to the Model-View-Control pattern. From the Ajax in the view, to the request and response in the controller, to the domain model wrapping the database, Rails gives you a pure-Ruby development environment. To go live, all you need to add is a database and a web server." ORM, MVC, JavaScript and templating for views...
Grails
"It's an open-source web application framework that leverages the Groovy language and complements Java Web development." Inspired by the Ruby on Rails framework (at least at one time it was.)
django
"Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design." ORM, MVC we're seeing a pattern here...
Symfony
"Based on the best practices of web development, thoroughly tried on several active websites, symfony aims to speed up the creation and maintenance of web applications, and to replace the repetitive coding tasks by power, control and pleasure." (PHP web framework)
Did I miss a dynlang/framework you enjoy working with? (most certainly...) Then drop me a line in the comments below and let me know what dynamic language or framework you use to get your job done!
P.S.
One of the best implementations of a dynamic/scripting language IDE around (non-trivial task): NetBeans Ruby Support (thanks Tor)
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