Continue with the Basics by Example; today's version of the post written in Cobra Enjoy!
You can copy and paste the code below in your favorite IDE/Editor and start playing and learning with it. This little "working" program will teach you the basics of the Programming Language.
There are some "comments" on the code added just to tell you what are or how are some features called. In case you want to review the theory, you can read my previous post, where I give a definition of each of the concepts mentioned on the code. You can find it here: http://carlosqt.blogspot.com/2010/08/new-series-languages-basics-by-example.html
Greetings Program - Verbose
# Cobra Basics
use System
namespace CobraGreetProgram
class Greet is public
# Fields or Attributes
var __message as String
var __name as String
var __loopMessage as int
#Properties
pro message as String is public
get
return __message
set
__message = .capitalize(value)
pro name as String is public
get
return __name
set
__name = .capitalize(value)
pro loopMessage as int is public
get
return __loopMessage
set
__loopMessage = value
# Constructor
cue init is public
base.init
__message = ''
__name = ''
__loopMessage = 0
# Overloaded Constructor
cue init(message as String, name as String, loopMessage as int) is public
base.init
__message = message
__name = name
__loopMessage = loopMessage
# Method 1
def capitalize(val as String) as String is private
# 'if-then-else' statement
if val.length >= 1
return val.capitalized
else
return ''
# Method 2
def salute is public
# 'for' statement
for i in __loopMessage
print '[__message] [__name]!'
# Overloaded Method 2.1
def salute(message as String, name as String, loopMessage as int) is public
# 'while' statement
i as int = 0
while i < loopMessage
print '[.capitalize(message)] [.capitalize(name)]!'
i+=1
# Overloaded Method 2.2
def salute(name as String) is public
# 'switch/case' statement is not supported
# using branch statement instead
dtNow as DateTime = DateTime.now
branch dtNow.hour
on 6 or 7 or 8 or 9 or 10 or 11, __message = 'good morning,'
on 12 or 13 or 14 or 15 or 16 or 17, __message = 'good afternoon,'
on 18 or 19 or 20 or 21 or 22, __message = 'good evening,'
on 23 or 0 or 1 or 2 or 3 or 4 or 5, __message = 'good night,'
else, __message = 'huh?'
print '[.capitalize(__message)] [.capitalize(name)]!'
# Console Program
class Program is public
def main is shared
# Define object of type Greet and Instantiate. Call Constructor
g as Greet = Greet()
# Call Set Properties
g.message = 'hello'
g.name = 'world'
g.loopMessage = 5
# Call Method 2
g.salute
# Call Overloaded Method 2.1 and Get Properties
g.salute(g.message, 'cobra', g.loopMessage)
# Call Overloaded Method 2.2
g.salute('carlos')
# Stop and Exit
print 'Press any key to exit...'
Console.read
Greetings Program - Minimal # Cobra Basics
class Greet
# Fields or Attributes
var __message
var __name
var __loopMessage
#Properties
pro message as String
get
return __message
set
__message = .capitalize(value)
pro name as String
get
return __name
set
__name = .capitalize(value)
pro loopMessage as int
get
return __loopMessage
set
__loopMessage = value
# Constructor
cue init
base.init
__message = ''
__name = ''
__loopMessage = 0
# Overloaded Constructor
cue init(message as String, name as String, loopMessage as int)
base.init
__message = message
__name = name
__loopMessage = loopMessage
# Method 1
def capitalize(val as String) as String is private
# 'if-then-else' statement
if val.length >= 1
return val.capitalized
else
return ''
# Method 2
def salute
# 'for' statement
for i in __loopMessage
print '[__message] [__name]!'
# Overloaded Method 2.1
def salute(message as String, name as String, loopMessage as int)
# 'while' statement
i = 0
while i < loopMessage
print '[.capitalize(message)] [.capitalize(name)]!'
i+=1
# Overloaded Method 2.2
def salute(name as String)
# 'switch/case' statement is not supported
# using branch statement instead
dtNow = DateTime.now
branch dtNow.hour
on 6 or 7 or 8 or 9 or 10 or 11, __message = 'good morning,'
on 12 or 13 or 14 or 15 or 16 or 17, __message = 'good afternoon,'
on 18 or 19 or 20 or 21 or 22, __message = 'good evening,'
on 23 or 0 or 1 or 2 or 3 or 4 or 5, __message = 'good night,'
else, __message = 'huh?'
print '[.capitalize(__message)] [.capitalize(name)]!'
# Console Program
class Program
def main
# Define object of type Greet and Instantiate. Call Constructor
g = Greet()
# Call Set Properties
g.message = 'hello'
g.name = 'world'
g.loopMessage = 5
# Call Method 2
g.salute
# Call Overloaded Method 2.1 and Get Properties
g.salute(g.message, 'cobra', g.loopMessage)
# Call Overloaded Method 2.2
g.salute('carlos')
# Stop and Exit
print 'Press any key to exit...'
Console.read
And the Output is:
Auto-Implemented Properties in Cobra
Auto-implemented properties enable you to quickly specify a property of a class without having to write code to Get and Set the property. The following code shows how to use them just like with VB.NET, C#, C++/CLI and so on.
pro <propname> [ as <type>] [from {var, <backingvariablename>} [= <initvalue>] ]
[<docstring>]
class Greet
var __message
var __name
var __loopMessage
#Properties
pro message from __message
pro name from __name
pro loopMessage from __loopMessage
# or you can just say from var as here below. it will look for
# fields called (_|__)message and (_|__)name and (_|__)loopMessage
# pro message from var
# pro name from var
# pro loopMessage from var
#Constructor
cue init
base.init
__message = ''
__name = ''
__loopMessage = 0
def capitalize(val as String) as String is private
return val.capitalized
def salute
print '[__loopMessage] [__message] [__name]!'
class Program
def main
g = Greet()
g.message = 'hello'
g.name = 'world'
g.loopMessage = 5
g.salute
Console.read
More about Properties in Cobra's wiki site: http://cobra-language.com/trac/cobra/wiki/Classes
And the Output is:
Unit Test and Contracts in Cobra
As stated in my series post, I'm covering strictly basics OO and other basics constructs on my code examples, but in Cobra's case I would like to add that the way you should be doing Cobra (or... the Cobra-nic style (like in Pythonic je...)) should be using Unit Tests and Contracts right from your code using test and require instructions. However, I will just show an example and keep the explanation for future posts.
Let's see an example
extend String
def capitalize as String
test
assert ''.capitalize == ''
assert 'x'.capitalize == 'X'
assert 'X'.capitalize == 'X'
assert 'cobrA'.capitalize == 'CobrA'
body
branch .length
on 0, return this
on 1, return .toUpper
else, return this[0].toString.toUpper + this[1:]
class Greet
cue init(name as String)
require name.length > 0
base.init
_name = name.capitalize
get name from var as String
def salute
print 'Hello [.name]!'
class GreetProgram
""" Greet the world! """
def main
g = Greet('world')
g.salute
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