The core control mechanism in f♭ is the conditional (ternary) operator choose word.
f♭> true 1 2 choose
[ 1 ]
f♭> clr false [ 3 ] [ 4 ] choose
[ [ 4 ] ]
If conditional values are quotes they must be evaluated to execute.
f♭> true [ 1 2 + ] [ 1 2 * ] choose
[ [ 1 2 + ] ]
f♭> clr true [ 1 2 + ] [ 1 2 * ] choose eval
[ 3 ]
f♭> clr false [ 1 2 + ] [ 1 2 * ] choose eval
[ 2 ]
Defining the word branch: [ choose eval ] ; allows simplified branching:
f♭> true [ 1 2 + ] [ 1 2 * ] branch
[ 3 ]
f♭> clr false [ 1 2 + ] [ 1 2 * ] branch
[ 2 ]
TBR
TBR