Happy strings

Yup, it's Dada again! I love useless things!

So, I was browsing through Think Python and found an exercise to print stuff on the screen. I figured it would be fun just to make it in one go - no loops or anything.

Here's how it looked. And by the way, you can run all the code in a Python interpreter - it's all safe.

1print \
2( ('+' + 5 * '-') * 3 + '+' + "\n" + \
3( ( '|' + 5 * ' ' ) * 3 + '|' + "\n" ) * 2 ) * 3 + \
4('+' + 5 * '-') * 3 + '+'

But then I figured... that's not nearly fun enough. So, long story short, I made this:

1print \
2',' + '_' * 2 + ',' + '\n' + \
3'(' + 'x' * 2 + ')' + '_' * 4 + '\n' + \
4'(' + '_' * 2 + ')' + ' ' * 4 + ')' + '\\' + '\n' \
5+ ' ' + 'U' + '|' * 2 + '-' * 2 + '|' * 2 + ' ' * 2 + '*'

Much more fun.

So then, I took it up a notch and wrote a program to generate that sort of thing. It took me three complete attempts, because I mostly produced bugs today... damn bugs. But it's all nice and thought-through now.

Here's the code:

1 #!/usr/bin/python
2 #
3 # Happy strings
4 # 
5 # More or less purposeless script, which takes strings, splits
6 # them up  into characters and then creates a Python print 
7 # statements which  reproduce the same strings in a 
8 # complicated, slightly less readable form... but a slightly 
9 # happier form, methinks.
10#
11# Parameters:
12#   a list of strings to reproduce
13# Author:
14#   Konrad Siek
15
16import sys
17
18def escape_string(string):
19    if string in ["\'", "\"", "\\"]:
20        return "\\" + string
21    elif string == "\n":
22        return "\\n"
23    return string
24
25def output_string(string, counter, last):
26    output = "'" + escape_string(string) + "'"
27    if counter != 1:
28        output += ' * ' + str(counter)
29    if not last:
30        output += ' + '
31    return output
32
33for string in sys.argv[1:]:
34    output = 'print '
35    previous = None
36    counter = 0 
37    length = len(string)
38    for i in range(0, length):
39        character = string[i]
40        if character == previous:
41            counter += 1
42        else:
43            if previous != None:                
44                output += output_string(
45                    previous, 
46                    counter, 
47                    False
48                )
49            counter = 1
50            previous = character
51    output += output_string(
52        previous, 
53        counter, 
54        True
55    )
56    print output
57

Yay!

The code is also available at GitHub as python/happy_strings.py.