From 32bc9ca5158720c68c47b0c67281887bffa7973b Mon Sep 17 00:00:00 2001
From: Glen Whitney <glen@studioinfinity.org>
Date: Fri, 25 Mar 2022 01:54:20 -0700
Subject: [PATCH] feat: Add complex numbers

  With just the operations we have for numbers, and overall tests.
---
 complex/add.js      | 16 ++++++++++++++++
 complex/all.js      | 12 ++++++++++++
 complex/complex.js  | 21 +++++++++++++++++++++
 complex/negate.js   |  6 ++++++
 number/number.js    | 16 ++++++++++------
 picomath.js         |  4 +++-
 picomathInstance.js |  4 ++++
 test/_picomath.js   |  8 ++++++++
 8 files changed, 80 insertions(+), 7 deletions(-)
 create mode 100644 complex/add.js
 create mode 100644 complex/all.js
 create mode 100644 complex/complex.js
 create mode 100644 complex/negate.js

diff --git a/complex/add.js b/complex/add.js
new file mode 100644
index 0000000..1293a14
--- /dev/null
+++ b/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
+       }])
+}
+                         
diff --git a/complex/all.js b/complex/all.js
new file mode 100644
index 0000000..76e5190
--- /dev/null
+++ b/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
+}
diff --git a/complex/complex.js b/complex/complex.js
new file mode 100644
index 0000000..794e689
--- /dev/null
+++ b/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})]
+   ])
+}
+
diff --git a/complex/negate.js b/complex/negate.js
new file mode 100644
index 0000000..a03e7de
--- /dev/null
+++ b/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})])
+}
diff --git a/number/number.js b/number/number.js
index 39476d5..b2f1b21 100644
--- a/number/number.js
+++ b/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)])
 }
diff --git a/picomath.js b/picomath.js
index 8a10a23..f8e88ad 100644
--- a/picomath.js
+++ b/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
diff --git a/picomathInstance.js b/picomathInstance.js
index c4b3420..04afd13 100644
--- a/picomathInstance.js
+++ b/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)
diff --git a/test/_picomath.js b/test/_picomath.js
index 4005d2b..84ff19b 100644
--- a/test/_picomath.js
+++ b/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)
+   })
 })