In section 3.4, we replace in it3a the abstract by the concrete expressions, simplify, replace iterators by list comprehensions, and introduce names for the intermediate values computed by the phases.
The parallel construct is the list and list comprehensions are compiled into potentially parallel loops.
List comprehensions provide an elegant, expressive means to concisely formulate certain patterns of calculation on lists.
If this behavior is achieved, then neither expressibility nor efficiency requires a separate syntax for array comprehensions.
List comprehensions consist of a generator and a filter.
Indeed, all of the languages discussed here use some parallel extension of list comprehensions and implicitly parallel higher-order functions such as map.
A prototype implementation has been developed providing, amongst other things, the first concrete implementation of monad comprehensions known to us at the time of writing.
Actually, genarray-with-loops are powerful array comprehensions, and fold-with-loops are versatile folding templates, both specifically designed for multi-dimensional arrays.
