Add std.clamp

[sbarzowski]

clamp(x, minVal, maxVal):: 
  if x  < minVal then minVal
  else if x > maxVal then maxVal
  else val

It seems like a quite natural and easy addition. Not a very huge value added, but it's a common little thing (and imo way more readable than std.min(lowerBound, std.max(x, upperBound))).

And when we are at it we can add std.inRange which checks if a value is within a given range.

[seh]

Would you verify that minVal is less than or equal to maxVal?

[sbarzowski]

Hmm... that's not obvious and it's actually an argument against std.inRange since it may not be obvious for the person reading the code as well.

Anyway, the function std.range is inclusive, so std.inRange should include maxVal too I guess.