Each transformation is represented as a Perl array. The first element is a
command that defines the transformation. For example ["noop"]
is a no-op
transformation. The remaining fields of the array are arguments. For example,
["echo", "Hello,", "world."]
is an echo transformation that prints
Hello, world.. The arguments need not be strings, for example
block is a list of further transformations:
["block", ["echo", "Mary had a little lamb,"], ["echo", "whose fleece was white as snow."], ["echo", "And everywhere that Mary went,"], ["echo", "the lamb was sure to go."], ]
Other transformations take other types of arguments (e.g., aggregate takes a hash).
The command must be one of the 20 basic transformations described in this
document, or a function defined in the %functions
hash.