need a function called decimal (val decimal = fn: string -> int) that takes a bit string corresponding to an integer and returns the decimal value of that integer. For example, decimal "10001" returns 17, decimal  "001101" returns  13. I've already done a decimal to binary though the function: fun binary(x)= if x<=1 then Int.toString(x) else binary(x div 2) ^ Int.toString( x mod 2);

Need help for SML programming lagauge. (Going from binary to decimal)

I need a function called decimal (val decimal = fn: string -> int) that takes a bit string corresponding to an integer and returns the decimal value of that integer. For example, decimal "10001" returns 17, decimal  "001101" returns  13.

I've already done a decimal to binary though the function:

fun binary(x)= if x<=1 then Int.toString(x) else binary(x div 2) ^ Int.toString( x mod 2);