248ef8ebb3
Closes #4021 Allows array ranges (e.g., `[0..10]`) to take expression instead of just numeric literals as their start and end values. Both expressions are required (we don't support `[0..]`, etc.). I've created a new kind of expression in the AST. The alternative was to represent the internals of an array as some kind of pattern which could initially be fully explicit or ranges. I figured the chosen version was simpler and easier to extend to open ranges, whereas the latter would be easier to extend to mixed ranges or other patterns. I chose simpler, it'll be easy enough to refactor if necessary. Parsing is tested implicitly by the tests of execution and unparsing. --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> Co-authored-by: Adam Chalmers <adam.chalmers@zoo.dev>
70 lines
90 KiB
Markdown
70 lines
90 KiB
Markdown
---
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title: "reduce"
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excerpt: "Take a starting value. Then, for each element of an array, calculate the next value,"
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layout: manual
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---
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Take a starting value. Then, for each element of an array, calculate the next value,
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using the previous value and the element.
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```js
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reduce(array: [KclValue], start: KclValue, reduce_fn: FunctionParam) -> KclValue
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```
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### Arguments
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| Name | Type | Description | Required |
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|----------|------|-------------|----------|
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| `array` | [`[KclValue]`](/docs/kcl/types/KclValue) | | Yes |
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| `start` | [`KclValue`](/docs/kcl/types/KclValue) | Any KCL value. | Yes |
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| `reduce_fn` | `FunctionParam` | | Yes |
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### Returns
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[`KclValue`](/docs/kcl/types/KclValue) - Any KCL value.
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### Examples
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```js
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fn decagon = (radius) => {
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step = 1 / 10 * tau()
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sketch001 = startSketchAt([cos(0) * radius, sin(0) * radius])
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return reduce([1..10], sketch001, (i, sg) => {
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x = cos(step * i) * radius
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y = sin(step * i) * radius
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return lineTo([x, y], sg)
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})
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}
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decagon(5.0)
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|> close(%)
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```
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```js
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array = [1, 2, 3]
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sum = reduce(array, 0, (i, result_so_far) => {
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return i + result_so_far
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})
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assertEqual(sum, 6, 0.00001, "1 + 2 + 3 summed is 6")
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```
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```js
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fn add = (a, b) => {
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return a + b
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}
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fn sum = (array) => {
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return reduce(array, 0, add)
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}
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assertEqual(sum([1, 2, 3]), 6, 0.00001, "1 + 2 + 3 summed is 6")
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```
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