From 7d150e28608123647d0bdcf8f0cffcff13c7edd5 Mon Sep 17 00:00:00 2001
From: Glen Whitney <glen@studioinfinity.org>
Date: Mon, 28 Apr 2025 16:02:26 -0700
Subject: [PATCH] feat: Add vector constructor/converter

---
 src/vector/Vector.js        |  5 +++++
 src/vector/__test__/type.js | 16 ++++++++++++++++
 src/vector/all.js           |  2 ++
 src/vector/type.js          | 12 ++++++++++++
 4 files changed, 35 insertions(+)
 create mode 100644 src/vector/__test__/type.js
 create mode 100644 src/vector/type.js

diff --git a/src/vector/Vector.js b/src/vector/Vector.js
index 0f82e4f..1fbf3f2 100644
--- a/src/vector/Vector.js
+++ b/src/vector/Vector.js
@@ -22,6 +22,10 @@ export const Vector = new Type(isVector, {
          specializesTo: VT => this.specializesTo(VT)
             && CompType.specializesTo(VT.Component),
          refine: (v, typer) => {
+            if (!v.length) {
+               throw new RangeError(
+                  `no way to refine ${typeName} on an empty vector`)
+            }
             const eltTypes = v.map(elt => CompType.refine(elt, typer))
             const newCompType = eltTypes[0]
             if (eltTypes.some(T => T !== newCompType)) {
@@ -35,6 +39,7 @@ export const Vector = new Type(isVector, {
    },
    specializesTo: VT => VT.vector,
    refine(v, typer) {
+      if (!v.length) return this.specialize(NotAType) // what else could we do?
       const eltTypes = v.map(elt => typer(elt))
       let compType = eltTypes[0]
       if (eltTypes.some(T => T !== compType)) compType = NotAType
diff --git a/src/vector/__test__/type.js b/src/vector/__test__/type.js
new file mode 100644
index 0000000..43dc101
--- /dev/null
+++ b/src/vector/__test__/type.js
@@ -0,0 +1,16 @@
+import assert from 'assert'
+import {NotAType} from '#core/Type.js'
+import math from '#nanomath'
+
+describe('Vector type functions', () => {
+   it('can construct a vector', () => {
+      const vec = math.vector
+      const {BooleanT, NumberT, Vector} = math.types
+      assert.deepStrictEqual(vec(3, 4, 5), [3, 4, 5])
+      assert.strictEqual(
+         vec.resolve([NumberT, NumberT, NumberT]).returns, Vector(NumberT))
+      assert.deepStrictEqual(vec(3, true), [3, true])
+      assert.strictEqual(
+         vec.resolve([NumberT, BooleanT]).returns, Vector(NotAType))
+   })
+})
diff --git a/src/vector/all.js b/src/vector/all.js
index b5fe798..81a3f9d 100644
--- a/src/vector/all.js
+++ b/src/vector/all.js
@@ -1 +1,3 @@
 export * as typeDefinition from './Vector.js'
+export * as type from './type.js'
+
diff --git a/src/vector/type.js b/src/vector/type.js
new file mode 100644
index 0000000..d826372
--- /dev/null
+++ b/src/vector/type.js
@@ -0,0 +1,12 @@
+import {Vector} from './Vector.js'
+import {NotAType, Returns} from '#core/Type.js'
+import {Any, Multiple, match} from '#core/TypePatterns.js'
+
+export const vector = match(Multiple(Any), (math, TV) => {
+   if (!TV.length) return Returns(Vector(NotAType), () => [])
+   let CompType = TV[0]
+   if (TV.some(T => T !== CompType)) CompType = NotAType
+   return Returns(Vector(CompType), v => v)
+})
+
+