eclipse-aascw / aas-core-codegen

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Compose the TypeScript XML de-serialization (#698)

The XML de-serialization in TypeScript was written out property by property.
Instead, we give every parser one shape,

    type ContentParser<T> = (cursor) => Either<T, DeserializationError>

and compose them.

The framing is shared as well. ``parseElementContent`` parses the content and
consumes the closing tag; ``parseNamedElement`` is that plus an opening tag,
which retires both ``parseNamedVElement`` and ``parseNamedClassElement`` --
they only ever differed in what they read between the tags, and that is now
the argument. The property loop calls the tail directly, since it has already
read the opening tag and switched on its local name; there is deliberately
no third framer for a property, as it would duplicate ``parseNamedElement``
for the sake of one check. That check, that a property does not occur twice,
sits in front of the parse instead, and only the message it reports is
shared, in ``duplicatePropertyError``.

No closure is allocated any more. The previous code built its item parser
as an arrow at the call site. Everything is now a hoisted function
declaration, composed by passing function references, so the order in which
we emit them does not matter either.

``xmlization.ts`` for the AAS meta-model goes from 17,216 to 11,439 lines:
the class parsers from 12,176 to 6,498 (-47%) and the dispatchers from 1,773
to 1,144 (-35%).

397 of 413 new or added lines in 1 file covered. (96.13%)

34139 of 40003 relevant lines covered (85.34%)

2.56 hits per line