Does anyone write JSL using functional programming, and if so do you have a standard set of functions that you use?

As an example, the simplified map function below does all of the work of a for loop so you only need to specify an expression and a list and the function returns a list with the function evaluted for each element. In R, a similar function and variants of it can be found in the package 'purrr' by Lionel Henry and Hadley Wickham.

```
// A function to evaluate an expression for each item in a list
//
// x__ A list
// fn__ An expression containing ___ (three underscores) that
// is replaced with each element of x__
//
// Returns a list the same length as x__.
//
map = function( {x__, fn__},
r__ = {};
for(i__ = 1, i__ <= N items( x__ ), i__++,
r__ = Insert( r__, Eval( substitute(Name Expr( fn__ ), Expr(___), Expr( x__[i__] ) ) ) );
);
return(r__);
);
//Data to evaluate
vals = { 1, 2, 3, -3, -2, 0.5, -1.1, 5.3, 2.7, 0 };
//number of entries above zero
map( vals, Expr( ___ > 0 ) );
//sum of fractional parts
sum( map( vals, Expr( Mod( ___, 1 ) ) ) );
```