psfried / dgen Goto Github PK

Generating timestamps is a pretty common thing, so it would be nice to have some ways of generating them out of the box. A reasonable function signature might be something like def format_datetime(format_string: String, time_zone: String, epoch_time_seconds: Int, subsecond_nanos: Uint). We could then use the chrono crate to create the date objects and format them using the given format string.

With that builtin function, we could then add a standard time module that builds on it to add some common useful functions for things like creating iso-8601 timestamps with UTC time, or things that generate sequential timestamps.

Functions like add, mul, div, mod, max, min, abs, etc, would be very useful for generating more complex data, or for formats where there's some constraints like "a string at least n bytes long". We should add them as builtin functions.

One thing we'd need to decide is how to handle overflow. Should we default to only wrapping or only erroring, or should we create separate functions for each way of handling overflow?

Option A: wrapping_mul(a: Uint, b: Uint) wraps on overflow and mul(a: Uint, b: Uint) errors on on overflow
Option B: mul(a: Uint, b: Uint) always either wraps or errors on overflow
Option C: maybe something else?