Extend sum function to work with vectors

nicklockwood · nicklockwood · commit 7ee23a3639ac · 2025-10-12T17:54:06.000+01:00
diff --git a/ShapeScript/StandardLibrary.swift b/ShapeScript/StandardLibrary.swift
@@ -496,9 +496,20 @@ extension Symbols {
         "min": .function(.list(.number), .number) { value, _ in
             .number(value.doublesValue.min() ?? 0)
         },
-        "sum": .function(.list(.number), .number) { value, _ in
-            let values = value.tupleValue as! [Double]
-            return .number(values.reduce(0, +))
+        "sum": .function(.list(.list(.number)), .list(.number)) { value, _ in
+            let values = value.tupleValue as! [[Double]]
+            if values.count == 1 {
+                return .number(values[0].reduce(0, +))
+            }
+            // Vector sum
+            var columns = values.reduce(0) { Swift.max($0, $1.count) }
+            var sums = [Double](repeating: 0, count: columns)
+            for vector in values {
+                for i in vector.indices {
+                    sums[i] += vector[i]
+                }
+            }
+            return sums.isEmpty ? 0 : .tuple(sums.map { .number($0) })
         },
         "sqrt": .function(.number, .number) { value, _ in
             .number(sqrt(value.doubleValue))
diff --git a/ShapeScriptTests/StandardLibraryTests.swift b/ShapeScriptTests/StandardLibraryTests.swift
@@ -1053,6 +1053,41 @@ final class StandardLibraryTests: XCTestCase {
         XCTAssertEqual(delegate.log, [0.0, 0.0, 1.0])
     }
 
+    func testScalarSum() {
+        let program = "print sum 1 2 3"
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [6.0])
+    }
+
+    func testVectorSum() {
+        let program = "print sum (1 2 3) (4 5 6) (7 8 9)"
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [12.0, 15.0, 18.0])
+    }
+
+    func testMixedWidthVectorSums() {
+        let program = "print sum (1 2) (3 4 5 6) (7 8 9)"
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [11.0, 14.0, 14.0, 6.0])
+    }
+
+    func testEmptyTupleSum() {
+        let program = "print sum ()"
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [0.0])
+    }
+
+    func testMultiEmptyTupleSum() {
+        let program = "print sum (() () ())"
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [0.0])
+    }
+
     func testLength() {
         let program = "print length(3 4)"
         let delegate = TestDelegate()
diff --git a/docs/ios/functions.md b/docs/ios/functions.md
@@ -95,13 +95,6 @@ max 2 4 // returns 4
 max 5 0 -5.1 // returns 5
 ```
 
-The `sum` function returns the sum of two or more values:
-
-```swift
-sum 2 4 // returns 6
-sum 5 0 -5.1 // returns -0.1
-```
-
 ## Linear Algebra
 
 ShapeScript also includes functions for operating on [vectors](literals.md#vectors-and-tuples):
@@ -136,6 +129,14 @@ define v (3 4)
 print normalize(v) // returns 0.6 0.8
 ```
 
+The `sum` function returns the sum of two or more values. It works with both scalar and vector inputs:
+
+```swift
+sum 2 4 // returns 6
+sum 5 0 -5.1 // returns -0.1
+sum (1 2 3) (4 5 6) // returns (5 7 9)
+```
+
 ## Trigonometry
 
 For the most part, you can avoid the need for trigonometry in ShapeScript by using the built-in [transform commands](transforms.md#relative-transforms) to manipulate geometry rather than manually calculating the positions of vertices.
diff --git a/docs/mac/functions.md b/docs/mac/functions.md
@@ -95,13 +95,6 @@ max 2 4 // returns 4
 max 5 0 -5.1 // returns 5
 ```
 
-The `sum` function returns the sum of two or more values:
-
-```swift
-sum 2 4 // returns 6
-sum 5 0 -5.1 // returns -0.1
-```
-
 ## Linear Algebra
 
 ShapeScript also includes functions for operating on [vectors](literals.md#vectors-and-tuples):
@@ -136,6 +129,14 @@ define v (3 4)
 print normalize(v) // returns 0.6 0.8
 ```
 
+The `sum` function returns the sum of two or more values. It works with both scalar and vector inputs:
+
+```swift
+sum 2 4 // returns 6
+sum 5 0 -5.1 // returns -0.1
+sum (1 2 3) (4 5 6) // returns (5 7 9)
+```
+
 ## Trigonometry
 
 For the most part, you can avoid the need for trigonometry in ShapeScript by using the built-in [transform commands](transforms.md#relative-transforms) to manipulate geometry rather than manually calculating the positions of vertices.
diff --git a/docs/src/functions.md b/docs/src/functions.md
@@ -95,13 +95,6 @@ max 2 4 // returns 4
 max 5 0 -5.1 // returns 5
 ```
 
-The `sum` function returns the sum of two or more values:
-
-```swift
-sum 2 4 // returns 6
-sum 5 0 -5.1 // returns -0.1
-```
-
 ## Linear Algebra
 
 ShapeScript also includes functions for operating on [vectors](literals.md#vectors-and-tuples):
@@ -136,6 +129,14 @@ define v (3 4)
 print normalize(v) // returns 0.6 0.8
 ```
 
+The `sum` function returns the sum of two or more values. It works with both scalar and vector inputs:
+
+```swift
+sum 2 4 // returns 6
+sum 5 0 -5.1 // returns -0.1
+sum (1 2 3) (4 5 6) // returns (5 7 9)
+```
+
 ## Trigonometry
 
 For the most part, you can avoid the need for trigonometry in ShapeScript by using the built-in [transform commands](transforms.md#relative-transforms) to manipulate geometry rather than manually calculating the positions of vertices.
