Question: I have an ASCII-art box and I need a program to open it.

Examples
--------

Input:

```
-------
|     |
|_____|

```

Output:

```
      /
     /
    /
   /
  /
 /
/
|     |
|_____|

```

Specification
=============

* The first line will only consist of `-`, at least 3 of them
* The middle rows will start with `|` have spaces, and end with `|`
	+ All the middle rows will be the same
* The last row will start with `|` have `_` and end with a `|`
* All rows will be the same length

Opening the box:

* Each `-` should be replaced by a `/` in ascending lines and position.

Answer: 
CJam, 14 bytes
==============

```
l,{N'/@S*}%W%q

```

[Try it online!](http://cjam.tryitonline.net/#code=bCx7TicvQFMqfSVXJXE&input=LS0tLS0tLQp8ICAgICB8CnxfX19fX3w)

### How it works

```
l               Read the first line from STDIN.
 ,              Compute the line's length. Result: L
  {      }%     Map; for each I in [0 ... L-1]:
                  (implicit) Push I.
   N              Push a linefeed.
    '/            Push a slash.
      @           Rotate I on top of the stack.
       S*         Turn I into a string of I spaces.
           W%   Reverse the resulting array of strings and characters.
             q  Read the remaining input from STDIN.

```
Python 2, 100 bytes
===================

```
def o(b):
 m=b.split('\n')[1:]
 print"\n".join(["/".rjust(i)for i in range(len(m[0]),0,-1)]+m)

```

Defines a function `o` that takes a string as its input. (Full program wasn't specified in the question).