Sorting

Sorting criteria are used in two situations:

in the order-by attributes of cycles, supported by all of them in some way except for for-range
as basic boolean binary operator in the RPN virtual machine

The two implementations are not unified, so feature parity is desirable but not intrinsic.

For cycles#

Each entry is a pair type:comparator with type either ASC, DESC or RANDOM.
If not provided, comparator is assumed to be the default one.
As an alternative comparator we could have a one using . to separate values in tokens, and order them token by token.

Ordering method#

`ASC` & `DESC`#

Whatever ordinal is assigned to the entries, sorting is just based on an ascending or descending order.

`RANDOM`#

Data of any type is first hashed, and asc is applied to those hashes. For integers, floats and booleans this just involves their immediate data.
For strings the characters buffer is used as the hash source. If the dot notation is needed, each token separated by . will be hashed and compared on its own. Nodes should not be directly compared. Doing so is not illegal, just nonsensical.

Comparison operators for supported types.#

Nodes#

Via suffix :n or :node.
Nodes should not be directly compared.
Doing so is not illegal, just nonsensical and UB.
A more precise semantic for this case might be introduced later on.

Attributes#

They are always cast to string before evaluation. So they will not be compared as XML nodes.

Integers#

Via suffix :i, :int or :integer.
Comparison as expected from any basic math class.

Floats#

Via suffix :f, `:float``.
Comparison as expected from any basic math class.

Booleans#

Via suffix :b, :bool or :boolean.
true is smaller than false.

Strings#

Strings are by far the most complex to handle as multiple criteria are possible.

Encoding ordering#

Via suffix :s, :str or :string. Based on the binary representation of UTF-8 encoding.

Natural ordering#

Via suffix :ns, :natstr or :natural-string. hello10 bigger than hello2.

Lexicographic ordering#

Via suffix :ls, :lexistr or :lexi-string. For symbols in the Latin alphabet this is more or less equivalent to the encoding ordering.
However, different languages have totally different customary approaches, and are not often based on alphabets.
Basically any criteria rooted in linguistic arguments goes in here.