comparison groovy and other languages

A very nice comparison, Groovy and other languages

http://pleac.sourceforge.net/

groovy:  http://pleac.sourceforge.net/pleac_groovy/index.html
PHP:  http://pleac.sourceforge.net/pleac_php/index.html

groovy: how to compile and run a groovy-pogramm stand alone

 Hi,

as groovy is interpreted (better: compiled every time) as it runs,
I found a nice idea, to compile the programm and let it run.

for the complete solution, look at  :
http://docs.codehaus.org/display/GROOVY/WrappingGroovyScript

very easy going

 fest@maxdata:~/intranet/htdocs/gutacht/versand> groovy wrapper.groovy -c -m pdf
     [echo] Compiling pdf.groovy
      [jar] Building jar: /home/fest/intranet/htdocs/gutacht/versand/pdf.jar
     [echo] Run script using: 'java -jar pdf.jar ...'
fest@maxdata:~/intranet/htdocs/gutacht/versand>
fest@maxdata:~/intranet/htdocs/gutacht/versand>
fest@maxdata:~/intranet/htdocs/gutacht/versand> java -jar pdf.jar 1 2 3
Anzahl Argumente 3
Usage:  pdf  Gutachten-nr  Datei  Zeile1  Zeile
fest@maxdata:~/intranet/htdocs/gutacht/versand>

This is the wrapper.groovy

/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Wrap a script and groovy jars to an executable jar
 */
def cli = new CliBuilder()
cli.h( longOpt: 'help', required: false, 'show usage information' )
cli.d( longOpt: 'destfile', argName: 'destfile', required: false, args: 1, 'jar destintation filename, defaults to {mainclass}.jar' )
cli.m( longOpt: 'mainclass', argName: 'mainclass', required: true, args: 1, 'fully qualified main class, eg. HelloWorld' )
cli.c( longOpt: 'groovyc', required: false, 'Run groovyc' )

//--------------------------------------------------------------------------
def opt = cli.parse(args)
if (!opt) { return }
if (opt.h) {
  cli.usage();
  return
}

def mainClass = opt.m
def scriptBase = mainClass.replace( '.', '/' )
def scriptFile = new File( scriptBase + '.groovy' )
if (!scriptFile.canRead()) {
   println "Cannot read script file: '${scriptFile}'"
   return
}
def destFile = scriptBase + '.jar'
if (opt.d) {
  destFile = opt.d
}

//--------------------------------------------------------------------------
def ant = new AntBuilder()

if (opt.c) {
  ant.echo( "Compiling ${scriptFile}" )
  org.codehaus.groovy.tools.FileSystemCompiler.main( [ scriptFile ] as String[] )
}

def GROOVY_HOME = new File( System.getenv('GROOVY_HOME') )
if (!GROOVY_HOME.canRead()) {
  ant.echo( "Missing environment variable GROOVY_HOME: '${GROOVY_HOME}'" )
  return
}

ant.jar( destfile: destFile, compress: true, index: true ) {
  fileset( dir: '.', includes: scriptBase + '*.class' )

  zipgroupfileset( dir: GROOVY_HOME, includes: 'embeddable/groovy-all-*.jar' )
  zipgroupfileset( dir: GROOVY_HOME, includes: 'lib/commons*.jar' )
  // add more jars here

  manifest {
    attribute( name: 'Main-Class', value: mainClass )
  }
}

ant.echo( "Run script using: \'java -jar ${destFile} ...\'" )

groovy: command line parameter / argument handling

Hi,

used from C, but there is not argc, argv.

it´s

args (Arry og arguments) and
args.size()  number of arguments

Like this

if ( args.size() != 4  )
  { println "Anzahl Argumente " + args.size()
    println "Usage:  pdf  Gutachten-nr  Datei  Zeile1  Zeile"
    return
  }

def nr = args[0]
def datei = args[1]
def zeile1 = args[2]
def zeile2 = args[3]

groovy first example: Hello World

the must in every language, teh hello world

println "hello World"

nothing more than this.

make it more complicate

def hello="hello"
def world="world"
println hello+" " +world
println "$hello $world"

Put this in a file  hello.groovy

and command

groovy hello.groovy 

So nice feature,

no ;
no main
no $  (only in the strings)
no ()   after the function println, as long, as all is cllear enough 

And the "def" gives a little more clarity,
other than in PHP,where every varibale, you write $abc or $abd
are varibales implizit declared.

Installing groovy

Look  at the introduction at
http://groovy.codehaus.org/Installing+Groovy

Short abstract

These instructions describe how to install a binary distribution of Groovy.

• first, Download a binary distribution of Groovy and unpack it into some file on your local file system
• set your GROOVY_HOME environment variable to the directory you unpacked the distribution
• add GROOVY_HOME/bin to your PATH environment variable
• set your JAVA_HOME environment variable to point to your JDK.

It did it on windows,

first test is a DOS command-windows and there print  "groovy -version" and you see,
wether all is fine and installed

Grails: first steps

What are the first steps to grails heaven ?

http://groovy.codehaus.org/ (groovy)
http://grails.org/ (Grails, comes with groovy included)

a nice IDE (STS) comes comes
http://www.grails.org/STS+Integration

How to install grails, an excellent leed in grails
http://www.grailsexample.net/  (still unter construction)

But in the next step, we start with groovy.

some more reference to the newbie 
http://groovy.codehaus.org/For+those+new+to+both+Java+and+Groovy