| 1 | const __provide__ = :| identity max min abs |
|
| 2 |
|
| 3 | func identity(x) {
|
| 4 | ### The identity function. Returns its argument.
|
| 5 |
|
| 6 | return (x)
|
| 7 | }
|
| 8 |
|
| 9 | func __math_select(list, cmp) {
|
| 10 | ## Internal helper for `max` and `min`.
|
| 11 | ##
|
| 12 | ## NOTE: If `list` is empty, then an error is thrown.
|
| 13 |
|
| 14 | if (len(list) === 0) {
|
| 15 | error "Unexpected empty list" (code=3)
|
| 16 | }
|
| 17 |
|
| 18 | if (len(list) === 1) {
|
| 19 | return (list[0])
|
| 20 | }
|
| 21 |
|
| 22 | var match = list[0]
|
| 23 | for i in (1 .. len(list)) {
|
| 24 | setvar match = cmp(list[i], match)
|
| 25 | }
|
| 26 | return (match)
|
| 27 | }
|
| 28 |
|
| 29 | func max(...args) {
|
| 30 | ## Compute the maximum of 2 or more values.
|
| 31 | ##
|
| 32 | ## `max` takes two different signatures:
|
| 33 | ## - `max(a, b)` to return the maximum of `a`, `b`
|
| 34 | ## - `max(list)` to return the greatest item in the `list`
|
| 35 | ##
|
| 36 | ## So, for example:
|
| 37 | ##
|
| 38 | ## max(1, 2) # => 2
|
| 39 | ## max([1, 2, 3]) # => 3
|
| 40 |
|
| 41 | case (len(args)) {
|
| 42 | (1) { return (__math_select(args[0], max)) }
|
| 43 | (2) {
|
| 44 | if (args[0] > args[1]) {
|
| 45 | return (args[0])
|
| 46 | } else {
|
| 47 | return (args[1])
|
| 48 | }
|
| 49 | }
|
| 50 | (else) { error "max expects 1 or 2 args" (code=3) }
|
| 51 | }
|
| 52 | }
|
| 53 |
|
| 54 | func min(...args) {
|
| 55 | ## Compute the minimum of 2 or more values.
|
| 56 | ##
|
| 57 | ## `min` takes two different signatures:
|
| 58 | ## - `min(a, b)` to return the minimum of `a`, `b`
|
| 59 | ## - `min(list)` to return the least item in the `list`
|
| 60 | ##
|
| 61 | ## So, for example:
|
| 62 | ##
|
| 63 | ## min(2, 3) # => 2
|
| 64 | ## max([1, 2, 3]) # => 1
|
| 65 |
|
| 66 | case (len(args)) {
|
| 67 | (1) { return (__math_select(args[0], min)) }
|
| 68 | (2) {
|
| 69 | if (args[0] < args[1]) {
|
| 70 | return (args[0])
|
| 71 | } else {
|
| 72 | return (args[1])
|
| 73 | }
|
| 74 | }
|
| 75 | (else) { error "min expects 1 or 2 args" (code=3) }
|
| 76 | }
|
| 77 | }
|
| 78 |
|
| 79 | func abs(x) {
|
| 80 | ## Compute the absolute (positive) value of a number (float or int).
|
| 81 |
|
| 82 | if (x < 0) {
|
| 83 | return (-x)
|
| 84 | } else {
|
| 85 | return (x)
|
| 86 | }
|
| 87 | }
|