feat: Add complex numbers

With just the operations we have for numbers, and overall tests.

complex/add.js

@@ -0,0 +1,16 @@
+import { anyComplex } from './complex.js'
+
+export default function create(pmath) {
+    const complex = pmath('complex')
+    return pmath('add', [anyComplex, // naive, but this is just a P-o-C
+       (...addends) => {
+           let sum = complex(addends[0])
+           for (let i = 1; i < addends.length; ++i) {
+               const addend = complex(addends[i])
+               sum.re += addend.re
+               sum.im += addend.im
+           }
+           return sum
+       }])
+}
+                         

complex/all.js

@@ -0,0 +1,12 @@
+import createComplex from './complex.js'
+import createAdd from './add.js'
+import createNegate from './negate.js'
+import createSubtract from '../generic/subtract.js'
+
+export default function create(pmath) {
+   createComplex(pmath)
+   createAdd(pmath)
+   createNegate(pmath)
+   createSubtract(pmath)
+   // not sure if there's anything reasonable to return here
+}

complex/complex.js

@@ -0,0 +1,21 @@
+/* Use a plain object with keys re and im for a complex */
+export function isComplex(z) {
+   return z && typeof z === 'object' && 're' in z && 'im' in z
+}
+
+export function anyComplex(args) {
+   for (let i = 0; i < args.length; ++i) {
+      if (isComplex(args[i])) return true
+   }
+   return false
+}
+
+export default function create(pmath) {
+   const number = pmath('number')
+   return pmath('complex', [
+      [args => args.length == 2, (x,y) => ({re: number(x), im: number(y)})],
+      [args => args.length == 1 && isComplex(args[0]), z => z],
+      [args => args.length == 1, x => ({re: number(x), im: 0})]
+   ])
+}
+

complex/negate.js

@@ -0,0 +1,6 @@
+import { isComplex } from './complex.js'
+
+export default function create(pmath) {
+    return pmath('negate', [args => args.length == 1 && isComplex(args[0]),
+       z => ({re: -z.re, im: -z.im})])
+}

number/number.js

@@ -1,14 +1,18 @@
+export function isNumber(x) {
+   return typeof x === 'number'
+}
+
 export function allNumbers(args) {
-    for (let i = 0; i < args.length; ++i) {
-        if (typeof args[i] !== 'number') return false
-    }
-    return true
+   for (let i = 0; i < args.length; ++i) {
+      if (!isNumber(args[i])) return false
+   }
+   return true
 }
 
 export function oneNumber(args) {
-    return args.length === 1 && typeof args[0] === 'number'
+   return args.length === 1 && isNumber(args[0])
 }
 
 export default function create(pmath) {
-    return pmath('number', [() => true, x => Number(x)])
+   return pmath('number', [() => true, x => Number(x)])
 }

picomath.js

@@ -1,8 +1,10 @@
 /* Core of picomath: generates an instance */
 import picomathInstance from './picomathInstance.js'
 import createNumbers from './number/all.js'
+import createComplex from './complex/all.js'
 
 const math = picomathInstance('math')
 createNumbers(math)
-    
+createComplex(math)
+
 export default math

picomathInstance.js

@@ -2,6 +2,10 @@
 import poortf from './poortf.js'
 
 export default function picomathInstance (instName) {
+    /* Since we have to do it all the time, when we call a picomath instance
+     * as a function, it takes a name and 0 or more implementations add adds
+     * them to its poortf property named name, returning that property value.
+     */
     function fn (name, imps) {
         if (name in fn) {
             fn[name].addImps(imps)

test/_picomath.js

@@ -12,4 +12,12 @@ describe('The default full picomath instance "math"', () => {
          (...addends) => addends.reduce((x,y) => x+y, '')])
       assert.strictEqual(math.add('Kilroy',' is here'), 'Kilroy is here')
    })
+
+   it('handles complex numbers', () => {
+      assert.deepStrictEqual(math.complex(2,3), {re: 2, im: 3})
+      assert.deepStrictEqual(
+         math.subtract(16, math.add(3, math.complex(0,4), 2)),
+         math.complex(11, -4))
+      assert.deepStrictEqual(math.negate(math.complex(3, '8')).im, -8)
+   })
 })