Options for more streamlined DSL for props() about ggvis

[hadley]

Another option from JJ. Like Option 4 + 5: := toggles the standard behaviour:

• scaled expr: x = ~mpg
• scaled cnst: x := 1
• scaled rctv: x := input_slider()
• unscld expr: fill := ~col
• unscld cnst: fill = "red"
• unscld rctv: fill = input_slider()
• prop obj : y = prop(...)

That way the standard operations (scaled expressions and unscaled constants) just work

[jcheng5]

Option 1.6

• scaled expr: x ~ mpg
• scaled cnst: x ~ I(1)
• scaled rctv: x ~ input_slider()
• unscld expr: fill = col
• unscld cnst: fill = I("red")
• unscld rctv: fill = input_slider()
• prop obj : y = prop(...)

I personally really like I() to distinguish between either expr vs. cnst, or scaled vs. unscaled.

[hadley]

@jcheng5 unfortunately that's really hard to make work because of the x ~ input_slider() - how do you tell if the rhs of the formula should be evaluated or unevaluated?

[jcheng5]

Oh, so is Option 1.5 equally hard to make work? That's what I was basing it off of.

[jcheng5]

Oh n/m I get it now.

[jcheng5]

Is option 3 workable?

[hadley]

@jcheng5 option 3 has the same problem - I can make it work with some heuristics, but it fail 1% of the time with weird error messages. Option 1.5 is easier to make work because it uses quote as well as ~.