List Commands Library for 50g

[DavidM]

Seeking opinions about the implementation of NL→I

NL→I (Number List to Integer) is intended as an easy/fast way to convert a list of numbers into an integer. I'd guess that 99% of the time it will be used to convert a list of single decimal digits to an integer made up of those digits, something like this:

Code:

{ 1 2 3 4 5 6 7 8 9 0 } NL→I => 1234567890

At present, the input list must contain only numbers (specifically integers or reals) or an error will result. This seems reasonable to me, as I would think that raising an error makes more sense than simply ignoring non-numeric objects embedded in the list, and trying to come up with something reasonable to do for non-numeric object types would erode the performance benefit.

Limiting the valid input in this way still leaves room for some ambiguous input, however. Reals with a fractional part seem fairly straightforward -- I just ignore the fractional part. But I'm pondering the best way to handle negative and |x|>=10 numbers. A potential list of numbers could be something like the following, and NL→I needs to be able to handle it appropriately:

Code:

{ 1.8 -3 15 10000.003 123456789 }

My inclination is to simply ignore the sign of any digits, thus implying that every result for NL→I will be positive. That forces the user to design their own way of tracking and applying the sign of final results, which seems like a reasonable approach given the possibility of having a mixture of signed/unsigned numbers in the input.

|x|>=10 numbers are less clear to me, though. I can think of several possibilities for those:

• "Cap" them to a 9
• "Normalize" them to a single digit
  • First significant digit?
  • Units digit?
  • |x| MOD 10?
  • Something else?
    
• Include all non-fractional digits in the final result, eg. { 123.456 7 8 9 } NL→I => 123789
• Something else I haven't yet pondered?
  

I can see both benefits and problems with each method above. What are your thoughts for a reasonable approach?