SML_BigIntLibrary

Biginteger library for SML (Standard ML) for doing integer operations on arbitrarily large integers.

Operations supported

It allows following integer operations(in the parenthesis, the corresponding function names are given)

• addition(add),
• subtraction(sub),
• multiplication(mul),
• division(div4bigint),
• mod(mod4bigint),
• comparisons:
  • equal to?(eq)
  • not equal to?(neq)
  • less than?(lt)
  • less than or equal to?(leq)
  • greater than?(gt)
  • greater than or equal to?(geq)

Usage

1. Copy biginteger.sml to the folder where lies the test sml file (call it test.sml).
2. Include the following line at the beginning of test.sml: use "biginteger.sml";
3. This library requires input in the form of string, instead of Integer (for the obvious reason that we want to do operations on integers of arbitrary length and int type of SML has a limit on its size). The string has to be converted to the biginteger type using str2bi function.

val a ="15" ;
val a_big = bigstruct.str2bi(a);

4. Use any of the operations given in Operations supported like this:

val c_big = bigstruct.add(a_big,b_big);

where a_big and b_big are of biginteger type.

5. Get back the string form from the biginteger form using bi2str function.

val c = bigstruct.bi2str(c_big);

Format of the input

All the functions take two biginteger as parameters. a $ b is equivalent to biginteger.operation(a,b) where operation is any of the operations given in Operations supported and $ is the symbol of operation. Note that a and b are of biginteger type. For example, to do a - b, do biginteger.sub(a,b)

Examples

All the examples are here.