This is a mirror of http://www.vim.org/scripts/script.php?script_id=895

In this version, the script can toggle:
    true     <->     false
    on       <->     off
    yes      <->     no
    define  <->     undef
    +        <->     -
    >        <->     <
    &&    <->     ||
    &     <->      |
    positive and negative numbers

Move the cursor on the word/char/number to be toggled and press
      <C-T>  in insert mode 
or
      +     in normal / insert mode.

This shortcut can be modified in the script file - of course...

If the cursor is positioned on a number, the script looks for a corresponding + or - sign for that number. 
If it's found, it will be replaced by the other one. If none is found, a - sign is inserted before the number.