Re: Problem with rotated points renderer VML (IE <9)
pull request was closed because the string "NaN" is a silly value for rotation to have. I consider the proper value NaN to be a reasonable value, but I notice that when a style's context method returns the value NaN, it gets coerced to a string when the token is interpolated.
a) add documentation clarifying that the application's context methods must guarantee not to return NaN,
b) OpenLayers.Style.createLiteral detects the string "NaN" and returns the value NaN instead.
c) OpenLayers.String.format detects when the template is entirely composed of one token, and in that case avoid coercing to a string.
I think a) is suboptimal, and if that's the decision is should be documented.
b) is a bit hacky but probably low risk, unless anyone's application relies on receiving the string "NaN"!
c) is the most appealing solution, but since OpenLayers.String.format is in wider use it is higher risk.