see also ARROW-5905, ARROW-7010

Reporter: Wes McKinney / @wesm
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [C++] C++ array kernels framework and execution buildout (umbrella issue) (is a child of)
• [C++] Support lossy casts from decimal128 to float32 and float64/double (relates to)
• [Python] support conversion to decimal type from floats? (relates to)
• [Python] Allow fast writing of Decimal column to parquet (is depended upon by)

PRs and other links:

• GitHub Pull Request #7612

_{Note: This issue was originally created as ARROW-7011. Please see the migration documentation for further details.}