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