String.FromCodePoints(arrayname,start,count)

bgrommes

Problem

Sometimes you want to return a substring and not an entire string from an array of code points. Currently to do that you would have to copy the array elements desired into a new array and pass that to FromCodePoints.

Proposed Solution

It would be much more efficient for FromCodePoints to just have optional start and length arguments for this use case.

Garry

This has now been implemented for the next release: https://feedback.objo.dev/feature/786

String.FromCodePoints() now has three forms:

String.FromCodePoints(codePoints)
String.FromCodePoints(codePoints, startIndex)
String.FromCodePoints(codePoints, startIndex, count)

The second form converts from startIndex to the end of the array. The third converts exactly count code points:

Var points() As Integer = [91, 65, 9829, 128640, 93]

Print(String.FromCodePoints(points, 1))     # A♥🚀]
Print(String.FromCodePoints(points, 1, 3))  # A♥🚀

These overloads read directly from the original array, avoiding the need to allocate and populate a temporary array.

startIndex may equal the array’s Count, and count may be zero, in which case an empty string is returned. Negative values or ranges extending beyond the array raise a runtime error.