Contents - Cultural View

Quark Framework 259
has proven to provide a good balance of flexibility and 'directness' when interfacing with external operations.
One of the main design goals for CAL was to make the language as comfortable as possible for mainstream
developers to pick up and use effectively. This is reflected in choices for syntax, but also in conventions and patterns
used within the standard libraries. For example, libraries use longer, descriptive names and are commented to explain
the implementations and best practices for use.
To see some CAL language source code click here [3] . This tutorial CAL module is designed as a top-to-bottom
'feature parade' to showcase basic syntax with examples of some built-in and user defined data structures.
Here are a few examples, derived from the tutorial module linked to in the preceding paragraph:
1. Quicksort
/**
* Here is a simple implementation of the quicksort algorithm for lists in
* CAL.
*
* Note: it is not the most efficient implementation, since it filters the
* list twice to partition.
*
* It is used here as an illustration. The production implementation of
* sorting on lists is
* {@link List.sort@}.
*
* The type of quicksort is constrained by the {@link Ord@} type class. This
* means that quicksort can sort list of any orderable type.
*/
quicksort :: Ord a => [a] -> [a];
quicksort list =
let
in
//partition_min is a local function of 1 argument
partition_min pivot = filter (\x -> x < pivot);
partition_max pivot = filter (\x -> x >= pivot);
case list of
[] -> [];
pivot : tail ->
;
quicksort (partition_min pivot tail)
++ (pivot : (quicksort (partition_max pivot tail)));
Note that CAL supports inline documentation comments, with embedded tags. Function type declarations
immediately precede the function definition. CAL supports type classes (e.g. Ord). Two local functions are declared
in the let block. Quicksort has a recursive definition, building up the output list at each level of recursion from the
sorts applied to the list of values either side of the pivot item.