program <- seq-element+ 

inset <- @inset ws+
ws <- [ \t]
nl <- [\n]
ws_or_nl <- ws/nl

seq-element <- "-" ws* string nl { (third data) } / nested-sequence
nested-sequence <- "-" ws* nl inset seq-element (@inset seq-element)* { (cons (fifth data) (zip-second (sixth data))) }

string <- "'" [ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz]+ "'" { (char-list-to-string (second data)) }