LearnBoost/stylus — pull request #1048 by mcfog (2013-06-11 15:44:41+00:00)
Title: hide property begin with $

I want to make use of property lookup to implement some powerful mixins which looks for parent block's property. e.g a dynamic semantic grid mixin
```
grid-ctn(containerwidth, col, padwidth = false)
$grid_width grid-devide(containerwidth, col)
$grid_col col
padwidth = grid-devide(containerwidth, col * 8) unless padwidth
$grid_padding grid-devide(padwidth, 2)

width containerwidth
position relative
clearfix()

grid-block(colspan)
float left
width (colspan * @$grid_width) - 2 * unit(@$grid_padding, '')
margin-left @$grid_padding
margin-right @$grid_padding

grid-pull(colspan)
margin-right colspan * @$grid_width + unit(@margin-right, '')

grid-push(colspan)
margin-left colspan * @$grid_width + unit(@margin-left, '')

grid-devide(width, division)
u = unit(width)
num = unit(width, '')

if u is '%'
unit(floor(num / division * 1000) / 1000, u)
else
unit(num / division, u)
```
so I can easily define a grid, where `grid-block` mixin would look for `$grid_xxx` property to decide its width&margin
```
.container
// grid-ctn 960px 12 5px
grid-ctn 100% 12
.halfblock
grid-block 6
&.center
grid-push 3
```

this works great except for the extra `$xx` property output, so I think hide $hidden property could be nice

inspired by #1014