From 9936d9941189cd9b4f8e4c85b461b6af0ba0a20f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Wed, 26 Feb 2020 14:51:06 +0100
Subject: [PATCH] [poincare] Add comment on Power::templatedApproximate

---
 poincare/src/power.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/poincare/src/power.cpp b/poincare/src/power.cpp
index 29d25e7c4..b086e6b4f 100644
--- a/poincare/src/power.cpp
+++ b/poincare/src/power.cpp
@@ -290,12 +290,14 @@ template<typename T> Evaluation<T> PowerNode::templatedApproximate(Context * con
     std::complex<T> c = static_cast<Complex<T> &>(base).stdComplex();
     T p = NAN;
     T q = NAN;
+    // If the power has been reduced, we look for a rational index
     if (childAtIndex(1)->type() == ExpressionNode::Type::Rational) {
       const RationalNode * r = static_cast<const RationalNode *>(childAtIndex(1));
       p = r->signedNumerator().approximate<T>();
       q = r->denominator().approximate<T>();
     }
-    // Spot form p/q with p, q integers
+    /* If the power has been simplified (reduced + beautified), we look for an
+     * index of the for Division(Rational,Rational). */
     if (childAtIndex(1)->type() == ExpressionNode::Type::Division && childAtIndex(1)->childAtIndex(0)->type() == ExpressionNode::Type::Rational && childAtIndex(1)->childAtIndex(1)->type() == ExpressionNode::Type::Rational) {
       const RationalNode * pRat = static_cast<const RationalNode *>(childAtIndex(1)->childAtIndex(0));
       const RationalNode * qRat = static_cast<const RationalNode *>(childAtIndex(1)->childAtIndex(1));
@@ -305,6 +307,9 @@ template<typename T> Evaluation<T> PowerNode::templatedApproximate(Context * con
       p = pRat->signedNumerator().approximate<T>();
       q = qRat->signedNumerator().approximate<T>();
     }
+    /* We don't handle power that haven't been reduced or simplified as the
+     * index can take to many forms and still be equivalent to p/q,
+     * with p, q integers. */
     if (std::isnan(p) || std::isnan(q)) {
       goto defaultApproximation;
     }