Number restrictions and interpretations

[monsterbitar]

It would be good if someone could clarify what the restrictions and interpretations are with regard to numbers in scripts.

• how small/big numbers can be used?
• what rounding options are available?
• how is rounding of negative numbers handled?

This is where I looked to see if it already existsed:

BitcoinCashSpecification/protocol/blockchain/script.md

[A60AB5450353F40E]

#33

[thesquaregroot]

@monsterbitar Does A60AB5450353F40E's addition answer your questions?

Given that scripts only handle integers, rounding isn't much of a concern. The only things that might need better specified are OP_DIV and OP_MOD, to clarify that they are performing standard (C-style) integer-division. Would that be useful or is this sufficiently addressed by the clarification that all the arithmetic operation are restricted to using integer operands?

[monsterbitar]

I think it would be useful, it would provide clarity and a point of reference in case people (like me) would feel uncertain about it.

[thesquaregroot]

@monsterbitar does the addition of the integer division page address your concerns here?

[monsterbitar]

If this is the only place where non-integer numbers can ever exist, then it at least provides a place where one can find an answer.

I would've prefered to have a page on "what is a script number" which is an easier place to find, and it could refer to the integer division page as a clarification of the only case where integer usage needs documentation.

[thesquaregroot]

Well, even here the numbers are only integers. The section of the Script page relating to arithmetic operations (here) does call out the following:

Numeric opcodes (OP_1ADD, etc) are restricted to operating on 4-byte integers. The semantics are subtle, though: operands must be in the range [-2^31 +1...2^31 -1], but results may overflow (and are valid as long as they are not used in a subsequent numeric operation).

Then further down for OP_DIV, and OP_MOD, it links to the integer division page when it mentions that they perform division. Is that more or less what you're asking for, or is there somewhere else you'd like to see this called out (or something it's not saying that should be called out)?