Adding Unpack Syntax to RCL (ruudvanasseldonk.com)

RCL, a new configuration language and JSON query tool, has introduced a significant feature in its latest version, v0.11.0: unpack syntax for lists and dictionaries. This new functionality allows users to easily assemble complex data structures by incorporating elements from existing lists and dictionaries using the syntax `..` for lists and sets, and `...` for dictionaries. This enhancement promises to improve the usability and readability of RCL by simplifying common operations like splicing lists or filling dictionaries with default values, which were previously cumbersome with comprehensions and the union operator. The addition of unpack syntax addresses key pain points in RCL’s design. While RCL's comprehensions were functionally expressive, they often resulted in verbose code, making it less enjoyable for developers to use. The union operator, while concise, posed formatting challenges and was less intuitive for newcomers. By opting for a straightforward unpacking approach, RCL not only streamlines syntax but also unifies the experience of manipulating collections. Notably, this implementation involves keeping sets distinct from dictionaries, as adopting a single unpack syntax for both could lead to ambiguity. Overall, this improvement enhances RCL's coherence, making it an attractive tool for developers working with JSON and configuration workflows.