chore: add a benchmark to get a feel for how fast scope variables are…

… resolved

test/benchmark/index.js

@@ -5,3 +5,4 @@ require('./roots')
 require('./matrix_operations')
 require('./prime')
 require('./load')
+require('./scope_variables.js')

test/benchmark/scope_variables.js

@@ -0,0 +1,22 @@
+// test performance of resolving scope variables in the expression parser
+
+const Benchmark = require('benchmark')
+const math = require('../..')
+
+const scope = { a: 2, b: 3, c: 4 }
+const f = math.evaluate('f(x, y) = a + b + c + x + y', scope)
+
+console.log('f(5, 6) = ' + f(5, 6))
+
+const results = []
+
+const suite = new Benchmark.Suite()
+let res = 0
+suite
+  .add('evaluate f(x, y)', function () {
+    res = f(-res, res) // just make it dynamic, using res as argument
+  })
+  .on('cycle', function (event) {
+    console.log(String(event.target))
+  })
+  .run()