Decimal work plan

We plan to present Decimal for Stage 1 at the February 2020 TC39 meeting. To get to Stage 2, it will be useful to accomplish the following tasks to further investigate both options:

• BigDecimal
  • Write complete reference documentation with examples
  • Implement a JSBI-style polyfill (#17) "JSBD"
  • Wrap the JSBD polyfill in a style using the operator overloading proposal
  • Write some larger, more realistic code samples (#34)
  • Write spec text
• Decimal128
  • Write complete reference documentation with examples
  • Implement a JSBI-style polyfill (#17) "JSD128"
  • Wrap the JSD128 polyfill in a style using the operator overloading proposal
  • Write some larger, more realistic code samples (#34)
  • Write spec text
• Implement Decimal literal syntax in Babel (#18)
• Scrub all bugs about semantic questions and ensure that we have good, initial answers
• Survey use cases and environment interactions more thoroughly and document results
• Determine which rounding modes and standard library functions to include

I plan to work on these, but there's a lot to do, and I could use help. If you want to get involved, feel free to respond to this issue; we can use it to coordinate task ownership.

Start by choosing one unchecked task in the BigDecimal, Decimal128, or shared-work sections, then read the referenced issues #17, #18, and #34 where applicable. The issue names no files or tests; completion should match the selected task's stated outcome, such as reference documentation, a polyfill, Babel literal support, spec text, or documented research.