How to use a column reference inside a formula inside of a column formula?

[#1]

If I have a column reference stored as a variable, call it clbColumn, how can I use this column for a given data table inside a function which is inside of a formula for a new column.

<JSL>

dt << New Column("Actual Timepoint", Numeric, Continuous, Formula(Date Difference(clbColumn, clbColumn2 "day") / 30.417));

<JSL>

[#2 · Accepted solution]

Insert one expression into another using Eval Insert, Eval Expr, Parse, and Substitute 

You will have to evaluate the references. Here is one example

Names Default To Here(1); 

dt = open("$SAMPLE_DATA/Big Class.jmp");

col1 = "height";
col2 = "weight";

Eval(Substitute(
	Expr(dt << New Column("Mult", Numeric, Continuous, Formula(
		_col1_ * _col2_
	))),
	Expr(_col1_), Name Expr(AsColumn(dt, col1)),
	Expr(_col2_), Name Expr(AsColumn(dt, col2)),
));