Cobra Forums

Hello I am new user. I am giving presentation on cobra tomorrow morning. Of course just I am giving an out line and little description about cobra. Its interesting. But due to less time I could not able to learn much. I have many doubts. But no time. From now on words I will regularly visit this site and even I love to work. Ok coming to my problem please send me TPK algorithm in cobra. How to execute this Trabb Pardo - Knuth algorith in cobra. Please send me now. From morning I am trying. Please help. Can any one send me now. please mail to my Email id sundeep325@gmail.com

sundeep325 wrote:Ok coming to my problem please send me TPK algorithm in cobra.

I couldn't find a Python version online, which would be easier to port to Cobra. The closest I've found is a Java version,I recommend you start there. It's a short algorithm so it shouldn't be difficult to translate to Cobra.

sundeep325 wrote:From morning I am trying

Then maybe it would be easier if you send us what you've got so far, and we can correct it.

Theres a Ruby version on the wikipedia entry for TPK algorithm which is pretty easy to convert to Cobra
( modulo a coupla things that may be bugs which I'll raise some tickets/questions for tomorrow)

sundeep325, you may feel free to use the slides from my Feb 2008 presentation at http://cobra-language.com/docs/papers-etc/Cobra-Socal-Piggies-2008-02-Slides.pdf. The first 19 slides are fairly accurate. The slides after that are somewhat out of date. If I had known about your presentation earlier, I would have updated them for you.

Interestingly, I have sometimes found it easier to port C# code to Cobra than Python or Ruby simply because C# comes with all the types and uses the .NET libraries. Also, the strongly typed version is also quite snappy. I'll have an LZW compression example soon based on such a port.

As i told u, im new, i dont have idea about this cobra. Just started 3 days before. I don't know what kind syntax use for what. So help me in giving an appropriate pgm. I am pasting here python program. please change it to cobra lang.

1 # tpk.py: Knuth's TPK program in Python
2
3 import sys,math
4
5 def f(x):
6 return math.sqrt(abs(x)) + 5.0*(x**3.0)
7
8 A = [] # declare a mutable sequence
9
10 # Read in the values of the array "A"
11 for i in range(11):
12 A.append (float(sys.stdin.readline()));
13
14 # In reverse order, apply "f" to each element of "A" and print
15 for i in range(10,-1,-1):
16 y = f (A[i])
17 if y<400.0:
18 sys.stdout.write ("%d %f\n" % (i,y))
19 else:
20 sys.stdout.write ("%d TOO LARGE\n" % i)

Here is the python program. And if possible try to not use magic numbers in the program. Like y<400, every thing we shld give at the run time. Please help me. thank for the replies.

And also is there any chance to get BNF notation for our cobra language, like <digit>--> {0|1|.....|9}.

k

There is currently no BNF, but here is some help:

(1) Check out the existing How-To's and Samples which you can present directly

http://cobra-language.com/how-to/

http://cobra-language.com/samples/

(2) Check out wiki docs which give some grammatical forms:

http://cobra-language.com/trac/cobra/wiki/AdditionalDoc

Before I forget heres a stab at the algorithm in Cobra,

Code: Select all

# use float (float64) not .Net Double, use Math.pow not **
class TPK
        def f(x as float) as float is shared
                # return Math.sqrt(Math.abs(x)) + 5.0f*x ** 3.0f # shld work but does not
                return Math.sqrt(Math.abs(x)) + 5.0f * Math.pow(x, 3.0f)

        def main is shared
                ray = []
                for i in 11     # or for i in 0 : 11
                        ray.add(float.parse(Console.readLine))
                ray.reverse
                for x in ray
                        y = .f(x)
                        print "[x] [if(y>400f, 'TOO LARGE', y)]"


                #Use this loop instead of above loop and ray.reverse to insert items in reverse order
                #for i in 11
                #       ray.insert(0, float.parse(Console.readLine))