Add "mixed" as a valid value for the "fraction" option for math.format

[jermowery]

Right now math.format allows for an options object to be passed as a second parameter.
This object may contain a fraction property with the values: "decimal" or "ratio"
Docs
Code

This FR is to add a new value for this property "mixed"

When "mixed" is specified then numbers will be formatted as mixed numbers, eg:

math.format(math.parse("1.25"), {fraction: "mixed"}) // 1 1/4
math.format(math.parse("1.25"),  {fraction: "decimal"}) // 1.25
math.format(math.parse("1.25"), {fraction: "ratio"}) // 5/4
math.format(math.parse("1.25")) // 1.25

Implementation should be as simple as adding another branch in the code linked above

[josdejong]

Interesting idea Jeremy, thanks for sharing. I like it.

A few thoughts:

1. I think the default behavior should stay the same, i.e. outputting decimals when option fraction is not configured. So math.format(math.parse("1.25")) should output 1.25 and not 5/4 as in your example, right?
2. I think so far all outputs of math.format can be fed directly into the expression parser again and evaluated. This option "mixed" would break that, since 1 1/4 is no valid input for the parser. That may be acceptable, and we could also look into making this valid syntax (maybe tricky with implicit multiplication, we'll have to see).

[jermowery]

1. Sorry, I thought ratio was the default. My intention in the example above was to keep the default the same. I will update the examples

Thanks for the reply!

[gwhitney]

Given the potential difficulties/API decisions/implications entailed in adding such an option which might produce output that can't be read back in, I think this belongs in a Discussion.