Bringing MATLAB Syntax into Kotlin

This talk was presented in BlrKotlin's meetup on 22nd Feb, 2020. This talk gives an idea of how powerful Kotlin's Operator Overloading feature is and how best we can use it to do our job.

Transcript

1. Bringing MATLAB like Syntax into Kotlin @iChanSek bit.ly/chansecode
2. MATLAB • Purpose - Specific • Syntax - • Code - Scientist or Mathematician Kotlin • Purpose - Generic • Syntax - • Code - Programmer @iChanSek bit.ly/chansecode
3. MATLAB (Pros) • Purpose - Specific • Syntax - • Code - Scientist or Mathematician Kotlin (Cons) • Purpose - Generic • Syntax - • Code - Programmer @iChanSek bit.ly/chansecode
4. MATLAB (Cons) • Separate Tooling • Learning Curve Kotlin (Pros) • Same Tooling • No Learning Curve @iChanSek bit.ly/chansecode
5. K-MAT @iChanSek bit.ly/chansecode Zero Learning Curve Same Tooling Syntax Mathematician Code
6. Ranges @iChanSek bit.ly/chansecode
7. start:end @iChanSek bit.ly/chansecode
8. start..end @iChanSek bit.ly/chansecode
9. start:spacing:end @iChanSek bit.ly/chansecode
10. start..end step spacing @iChanSek bit.ly/chansecode
11. start..step..end @iChanSek bit.ly/chansecode
12. start..step..end @iChanSek bit.ly/chansecode Operator Function
13. start..step..end @iChanSek bit.ly/chansecode rangeTo() Operator Function
14. start..step..end @iChanSek bit.ly/chansecode operator fun IntRange.rangeTo(end: Int): IntProgression { return if (last > 0) first..end step last else IntProgression.fromClosedRange(first, end, last) } Operator Function
15. (start..end)’ @iChanSek bit.ly/chansecode
16. (start..end).T @iChanSek bit.ly/chansecode
17. (start..end).T @iChanSek bit.ly/chansecode Extension Property
18. (start..end).T @iChanSek bit.ly/chansecode val IntRange.T: Array<IntArray> get() = arr.T Extension Property
19. (start..end).T @iChanSek bit.ly/chansecode val IntRange.T: Array<IntArray> get() = arr.T Extension Property
20. (start..end).T @iChanSek bit.ly/chansecode val IntRange.T: Array<IntArray> get() = arr.T val IntRange.arr: IntArray get() = toArray() Extension Property
21. (start..end).T @iChanSek bit.ly/chansecode val IntRange.T: Array<IntArray> get() = arr.T val IntRange.arr: IntArray get() = toArray() private fun IntRange.toArray(): IntArray { val result = IntArray(last - first + 1) forEachIndexed { index, i -> result[index] = i } return result } Extension Property
22. Indexing @iChanSek bit.ly/chansecode
23. array(index) @iChanSek bit.ly/chansecode
24. array[index] @iChanSek bit.ly/chansecode
25. array(start:end) @iChanSek bit.ly/chansecode
26. array[start..end] @iChanSek bit.ly/chansecode
27. array[start..end] @iChanSek bit.ly/chansecode Operator Function
28. array[start..end] @iChanSek bit.ly/chansecode get() Operator Function
29. array[start..end] @iChanSek bit.ly/chansecode operator fun IntArray.get(range: IntRange) = sliceArray(range) Operator Function
30. array(start:end) = 10 @iChanSek bit.ly/chansecode
31. array[start..end] = 10 @iChanSek bit.ly/chansecode
32. array[start..end] = 10 @iChanSek bit.ly/chansecode operator fun IntArray.set(range: IntRange, value: Int) { range.forEach { this[it] = value } } Operator Function
33. matrix(row, column) @iChanSek bit.ly/chansecode
34. matrix[row][column] @iChanSek bit.ly/chansecode
35. matrix[row, column] @iChanSek bit.ly/chansecode
36. matrix[row, column] @iChanSek bit.ly/chansecode operator fun Array<IntArray>.get(row: Int, col: Int) = this[row][col] Operator Function
37. matrix(row, colSt:colEnd) @iChanSek bit.ly/chansecode
38. matrix[row, colSt..colEnd] @iChanSek bit.ly/chansecode
39. matrix[row, colSt..colEnd] @iChanSek bit.ly/chansecode operator fun Array<IntArray>.get(row: Int, cols: IntRange) = this[row][cols] Operator Function
40. matrix[rowSt..rowEnd, column] @iChanSek bit.ly/chansecode operator fun Array<IntArray>.get(rows: IntRange, col: Int): Array<IntArray> { if (col < 0) throw Exception(“. . .”) if (rows.last < rows.first) return arrayOf() return Array(1 + rows.last - rows.first) { intArrayOf(this[rows][it][col]) } } Operator Function
41. matrix[rowSt..rowEnd, colSt..colEnd] @iChanSek bit.ly/chansecode operator fun Array<IntArray>.get(rows: IntRange, cols: IntRange): Array<IntArray> { if (rows.last < rows.first || cols.last < cols.first) return arrayOf() return Array(1 + rows.last - rows.first) { this[rows][it][cols] } } Operator Function
42. Arithmetic Operations @iChanSek bit.ly/chansecode
43. result = arr + 10 @iChanSek bit.ly/chansecode
44. val result = arr + 10 @iChanSek bit.ly/chansecode
45. val result = arr + 10 @iChanSek bit.ly/chansecode operator fun IntArray.plus(value: Int): IntArray { val resultArr = IntArray(size) forEachIndexed { index, i -> resultArr[index] = i + value } return resultArr } Operator Function
46. val result = arr * 10 @iChanSek bit.ly/chansecode operator fun IntArray.times(value: Int): IntArray { val resultArr = IntArray(size) forEachIndexed { index, i -> resultArr[index] = i * value } return resultArr } Operator Function
47. Thank You Chandra Sekhar @iChanSek bit.ly/chansecode