Code Golf: The wave

Question

x86 machine code (37 bytes)

Hexdump:

6800B807BF8007BE8200B40EAC3C0D741338D8740A720481EF400181C7A000AB86C3EBE8C3

Run in MS-DOS with 50 line console, the input is taken from the command line.

E.g.

wave.com 1234567890qwertyuiopasdfghjklzxcvbnm

Download binary here

Update: Shaved off three bytes thanks to jrandomhacker

J

54 characters, if you let the interpreter handle input/output.

e=:|:@((#&' '@],[)"0[:(-<./)0,[:+/\[:(}:(>-<)}.)a.i.])

65 to explicitly read from stdin and write to stdout.

(|:((#&' '@],[)"0[:(-<./)0,[:+/\[:(}:(>-<)}.)a.&i.)~1!:1[3)1!:2[4

   e '1234567890qwertyuiopasdfghjklzxcvbnm'
                             z
                            l x v n
                           k   c b m
                          j
                         h
                        g
               y   p s f
              t u o a d
           w r   i
        9 q e
       8 0
      7
     6
    5
   4
  3
 2
1

   e '31415926535897932384626433832795028841971693993751058209749445923078164062862'
            9 9   8 6 6
     9 6   8 7 3 3 4 2 4  8   9   88
3 4 5 2 5 5     2       33 3 7 5 2  4 9   9 99 7
 1 1     3                  2   0    1 7 6 3  3 5   8              8 6
                                        1        1 5 2 9      9 3 7 1 4 6 8
                                                  0   0 7 9  5 2 0     0 2 6
                                                         4 44               2

---

   NB. Look up ASCII codes
   ord =: a. i. ]
   ord 'p4ssw0rd'
112 52 115 115 119 48 114 100

   NB. Going up?
   up =: }: < }.
   up ord 'p4ssw0rd'
0 1 0 1 0 1 0

   NB. Going down?
   down =: }: > }.
   down ord 'p4ssw0rd'
1 0 0 0 1 0 1

   NB. Combine to get ±1
   updown =: }: (> - <) }.
   updown ord 'p4ssw0rd'
1 _1 0 _1 1 _1 1

   NB. Start with 0, follow up with partial sums
   sum =: 0 , +/\
   sum updown ord 'p4ssw0rd'
0 1 0 0 _1 0 _1 0

   NB. Subtract the minimum to get sequence with base at 0
   fix =: - <./
   fix sum updown ord 'p4ssw0rd'
1 2 1 1 0 1 0 1

   NB. For convenience, name this chain of functions
   d =: [: fix [: sum [: updown ord

   NB. Make spaces before the characters
   push =: (#&' ' @ ] , [)"0 d
   push 'p4ssw0rd'
 p
  4
 s
 s
w
 0
r
 d

   NB. Turn it on its side
   |: push 'p4ssw0rd'
    w r
p ss 0 d
 4

   NB. Combine into one named function…
   e =: |: @ push
   NB. …and inline everything
   e =: |:@((#&' '@],[)"0[:(-<./)0,[:+/\[:(}:(>-<)}.)a.i.])

The shortest code by character count to print a 'wave' from the input string.

Console.WriteLine("a 'wave' from the input string.");

Perl (94 characters)

144 characters originally by barnaba:

chop($_=<>);$l=length;push(@a," "x$l)for(1..$l*2);$l+=(ord $p<=>ord $_),substr($a[$l],$r++,1)=$p=$_ for(split //);/^\s+$/||print "$_\n" for(@a)

121 characters from optimization by Chris Lutz:

$_=<>;chop;$a[@a]=" "x$l for 1..($l=length)*2;$l+=$p cmp$_,substr($a[$l],$r++,1)=$p=$_ for split//;/\S/&&print"$_\n"for@a

94 characters from further optimization:

$_=<>;@a=($"x($l=y///c).$/)x(2*$l);s/./substr$a[$l+=$"cmp$&],"@-",1,$"=$&/ge;/\S/&&print for@a

Note that in traditional Perl golf, one usually adds the number of switches and the length of the code (which would help here by a few strokes), but here we're using stand-alone programs with no switches.

C on a VT100 terminal (76 characters)

This works in my test on FreeSBIE:

o;main(c){for(;(c=getchar())-10;o=c)printf("\33[1%c%c",c<o?66:c>o?65:71,c);}

But in order to see the output clearly, you have to run it with something like this:

clear ; printf "\n\n\n\n\n" ; echo the quick brown fox jumps over the lazy dog | ./a.out ; printf "\n\n\n\n\n"

Does this count?

Python (161 chars)

v,s="",raw_input()
m=n=len(s)
r=[' ']*n
q=[r[:]for i in range(2*n)]
for j,i in enumerate(s):
 m+=(i<v)-(i>v)
 q[m][j],v=i,i
for i in q:
 if i!=r:print''.join(i)

I haven't done much to compress it yet though. Porting it to something with a spaceship operator now.