Type casting / parsing operations

[divarvel]

We could introduce parsing operations, allowing to try converting strings into numbers, or JSON strings / bytearrays into map / arrays.

This would require null (#148) for parsing failures, but could give more flexibility)

syntax ideas

• as keyword. readable, but would make the grammar more complex
• as_xxx() methods. a bit less readable and a tad more ad-hoc, but integrates nicely with the grammar