Walking straight forward

Walking Straight Forward is a programming language I made based on a song I made called Walking Straight Forward, the song goes like this:

Walking straight,
Walking straight,
Straight forward!
Walking straight,
Walking straight,
Straight forward!
Walking straight,
Walking straight,
Straight forward!
Stop.
Turn [direction],
Turn [direction].
{loops}

The structure of the program is the song, including the looping, if you want more stuff, the program looks like this:

Walking straight,
Walking straight,
Straight [command]!
Walking straight,
Walking straight,
Straight [input]!
Walking straight,
Walking straight,
Straight [input]!
Stop.
Turn [input],
Turn [input].
{loops}

Commands:

Forward, make the 1st input a var.
Backward, return the value of the 1st input as a var.
Leftward, add 1st input and 2nd input and put it in 3rd input as var.
Rightward, subtract 1st from 2nd into 3rd as var.
Nowhere, Set 1st to 2nd.

Inputs:

Forward, the number 1
Backward, the number -1
Leftward, the var 1
Rightward, the var 2
The same way, refer to the last returned value
Nowhere, the output, when set, outputs the value being set to
Left in turn, set this line to the var 1.
Right in turn, go to the line that is var 1.
Not at all in turn, do nothing there

123 program:

Walking straight,
Walking straight,
Straight Forward!
Walking straight,
Walking straight,
Straight Leftward!
Walking straight,
Walking straight,
Straight Nowhere!
Stop.
Turn Not at all,
Turn Not at all.
Walking straight,
Walking straight,
Straight Leftward!
Walking straight,
Walking straight,
Straight Leftward!
Walking straight,
Walking straight,
Straight Forward!
Stop.
Turn Not at all,
Turn Not at all.
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Leftward!
Stop.
Turn Not at all,
Turn Not at all.
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Leftward!
Stop.
Turn Not at all,
Turn Not at all.
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Nowhere!
Walking straight,
Walking straight,
Straight Leftward!
Stop.
Turn Not at all,
Turn Not at all.