Deconstruct

Builder supports destructuring assignment syntax for R, similar to JavaScript and Python.

Use the .[var1, var2, ...] syntax to extract multiple values from a list:

.[x, my_var] <- call()

That will produce:

.destructure_tmp_ <- call()
x <- .destructure_tmp_[[1]]
my_var <- .destructure_tmp_[[2]]

The expression on the right-hand side is evaluated once and stored in a hidden temporary variable (.destructure_tmp_). Each variable is then assigned from the corresponding index of that temporary. This ensures:

• Side effects only occur once
• Expensive computations aren’t repeated
• Consistent behavior with functions that return different values on each call

Variables are assigned in order using list accessor [[1]], [[2]], etc. This makes it convenient to work with functions that return multiple values in a list.