Returns the value of a variable; varname is provided as a quoted string. This is useful for variables which contain characters that would confuse the Evaluator's parser (e.g. if the name begins with a number, or contains a colon).

Example:

flag = Val("35mmfocallength"); // get value of the 35mmfocallength field

If the deref parameter is set to true, it causes the named variable to be dereferenced. That is, the named variable should hold a string which is the name of another variable, and the function will return the value of that second variable. For example,

a = "b";
b = "c";
Output(Val(a)); // -> "b"
Output(Val(a, true)); // -> "c"