Scope Reduction

[emdash]

This project has stalled, I think this is largely due to scope creep.

New focus: "uDLang is a typesafe, pure-functional successor to Awk which operates on structured data".

What's on the block:

• builtin formats besides msgpack
• subjunctives
  • this feature is just weird, and I don't think it is sound.
• interleaved side effects
  • they break referential transparency.
  • force us to cache or re-evaluate any side-effecting expr, and thereby defeats inlining
  • out will remain as a way to control execution.
  • like POSIX exit(), except it outputs the result of evaluating its expression argument.
  • introducing the companion, pass, which aborts the current cycle and outputs nothing.
  • guarantees exactly one reachable out statement along a given code path from the top-level.
  • any effort at being optimal for the moment.
  • language designed to make high performance possible later.
  • exceptions?

What's staying:

• records
• partial application (more important than I realized at first)
• "template" functions consuming block arguments
• guaranteed aggressive inlining and const folding
• adts via simple tagged unions
• whatever the mechanism, try/catch/finally will be the syntax for error handling

Simplifying assumptions:

• udlang will exclusively consume mspgack with binary frames on stdin.
• udlang core language will be provided by a single Rust binary, plus companion tools.
  • conversion to other formats
  • pre/post-processors for protocols in the standard library, plus common formats.
  • these can

Some related work with defined scope:

• make uDLang's available as a companion shared library
  • will demo a patched version of some shell (maybe busybox or toybox).
• input is a stream of msgpack records
• output is a stream of msgpack records

Minimal command-line flags will control

• input and output files, for shell invocations beyond I/O redirection.
  • support for consuming script from here doc, like sed / awk.
• debug output verbosity
• debug mode
  • at least text mode, but ideally we'd support GDB's remote protocol
• typecheck only mode, compatible with flycheck
• oneshot mode, with record constructed from argv