| 1 | """ |
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| 2 | Point.cobra |
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| 3 | |
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| 4 | This sample library class demonstrates numerous Cobra features including |
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| 5 | unit tests, contracts, properties, overrides, etc. in fairly small, |
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| 6 | easy-to-understand classes. |
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| 7 | |
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| 8 | You can run the test cases for this (and also test compile) like so: |
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| 9 | |
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| 10 | cobra -test Point.cobra |
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| 11 | |
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| 12 | Or build this into a Point.dll libary like so: |
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| 13 | |
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| 14 | cobra -t:lib -c Point.cobra |
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| 15 | |
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| 16 | Upon final delivery, you may wish to turn on optimizations while removing |
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| 17 | asserts, contracts and unit tests. You can do these individually or |
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| 18 | all in one fell swoop with the -turbo option: |
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| 19 | |
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| 20 | cobra -t:lib -turbo -c Point.cobra |
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| 21 | |
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| 22 | See cobra -h for more information. |
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| 23 | """ |
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| 24 | |
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| 25 | class Point |
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| 26 | """ |
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| 27 | An immutable point in 2D space with integer coordinates. |
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| 28 | |
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| 29 | Because points are immutable they can be put in sets and used as keys in dictionaries. |
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| 30 | """ |
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| 31 | |
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| 32 | test |
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| 33 | |
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| 34 | p1 = Point(1, 2) |
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| 35 | assert p1.x == 1 and p1.y == 2 |
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| 36 | assert p1.isPositive and not p1.isZero |
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| 37 | assert p1.toString == 'Point(1, 2)' |
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| 38 | |
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| 39 | p2 = p1.movedBy(3, 4) |
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| 40 | assert p2.x == 4 and p2.y == 6 |
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| 41 | assert p1 <> p2 |
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| 42 | |
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| 43 | p3 = Point(1, 2) |
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| 44 | assert p1 == p3 |
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| 45 | |
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| 46 | assert Point.zero.isZero |
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| 47 | |
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| 48 | points = {p1, p2, p3} # a Set |
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| 49 | # but p1 and p3 are not unique so: |
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| 50 | assert points.count == 2 |
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| 51 | assert p1 in points and p2 in points and p3 in points |
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| 52 | |
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| 53 | shared |
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| 54 | |
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| 55 | var _zero = Point(0, 0) |
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| 56 | |
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| 57 | get zero as Point |
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| 58 | """ |
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| 59 | Returns the zero point, (0, 0). |
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| 60 | This is cached and slightly faster than creating a new point every time. |
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| 61 | """ |
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| 62 | return _zero |
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| 63 | |
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| 64 | cue init(x as int, y as int) |
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| 65 | ensure .x == x and .y == y |
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| 66 | _x, _y = x, y |
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| 67 | |
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| 68 | get x from var as int |
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| 69 | |
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| 70 | get y from var as int |
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| 71 | |
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| 72 | get isPositive as bool |
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| 73 | return .x > 0 and .y > 0 |
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| 74 | |
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| 75 | get isZero as bool |
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| 76 | return .x == 0 and .y == 0 |
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| 77 | |
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| 78 | def movedBy(dx as int, dy as int) as Point |
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| 79 | ensure result.x == .x+dx and result.y == .y+dy |
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| 80 | return Point(_x+dx, _y+dy) |
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| 81 | |
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| 82 | def toString as String is override |
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| 83 | return '[.typeOf.name]([.x], [.y])' |
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| 84 | |
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| 85 | def equals(other as Object?) as bool is override |
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| 86 | if this is other, return true |
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| 87 | if other inherits Point |
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| 88 | return .x == other.x and .y == other.y |
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| 89 | else |
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| 90 | return false |
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| 91 | |
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| 92 | def getHashCode as int is override |
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| 93 | return .x ^ .y |
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