Brainfuck mode

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[ This program prints "Hello World!" and a newline to the screen, its
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  length is 106 active command characters [it is not the shortest.]
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​
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  This loop is a "comment loop", it's a simple way of adding a comment
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  to a BF program such that you don't have to worry about any command
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  characters. Any ".", ",", "+", "-", "<" and ">" characters are simply
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  ignored, the "[" and "]" characters just have to be balanced.
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]
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+++++ +++               Set Cell #0 to 8
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[
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    >++++               Add 4 to Cell #1; this will always set Cell #1 to 4
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    [                   as the cell will be cleared by the loop
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        >++             Add 2 to Cell #2
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        >+++            Add 3 to Cell #3
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        >+++            Add 3 to Cell #4
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        >+              Add 1 to Cell #5
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        <<<<-           Decrement the loop counter in Cell #1
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    ]                   Loop till Cell #1 is zero; number of iterations is 4
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    >+                  Add 1 to Cell #2
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    >+                  Add 1 to Cell #3
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    >-                  Subtract 1 from Cell #4
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    >>+                 Add 1 to Cell #6
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    [<]                 Move back to the first zero cell you find; this will
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                        be Cell #1 which was cleared by the previous loop
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    <-                  Decrement the loop Counter in Cell #0
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]                       Loop till Cell #0 is zero; number of iterations is 8
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​
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The result of this is:
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Cell No :   0   1   2   3   4   5   6
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Contents:   0   0  72 104  88  32   8
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Pointer :   ^
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​
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>>.                     Cell #2 has value 72 which is 'H'
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>---.                   Subtract 3 from Cell #3 to get 101 which is 'e'
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+++++++..+++.           Likewise for 'llo' from Cell #3
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>>.                     Cell #5 is 32 for the space
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<-.                     Subtract 1 from Cell #4 for 87 to give a 'W'
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<.                      Cell #3 was set to 'o' from the end of 'Hello'
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+++.------.--------.    Cell #3 for 'rl' and 'd'
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>>+.                    Add 1 to Cell #5 gives us an exclamation point
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>++.                    And finally a newline from Cell #6
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​

A mode for Brainfuck

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