From fb466b3520b569c9ac3034c9b7873b374055e1b2 Mon Sep 17 00:00:00 2001
From: Yann Weber <yann.weber@member.fsf.org>
Date: Mon, 14 May 2018 16:55:34 +0200
Subject: [PATCH] Bugfix in mutator when len(expr) == 1

---
 gte/mutator.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/gte/mutator.py b/gte/mutator.py
index 7050233..e32e397 100644
--- a/gte/mutator.py
+++ b/gte/mutator.py
@@ -40,9 +40,14 @@ def mutate(expr, force = True, mutcount = 1):
     return res
 
 def mutatef(expr, mutcount = 1):
-    mutations = [mutadd, mutdel]
+    mutations = [mutadd] * 3
+    if len(expr) > 1:
+        mutations += [mutdel] * 3
     mutations += [mutupdtype for _ in range(3)]
     mutations += [mutupdval for _ in range(6)]
+    #mutations = [mutadd, mutdel]
+    #mutations += [mutupdtype for _ in range(3)]
+    #mutations += [mutupdval for _ in range(6)]
     res = copy.copy(expr)
     for _ in range(mutcount):
         mutations[randint(0, len(mutations)-1)](res)
@@ -66,7 +71,10 @@ def mutupdtype(expr):
     return expr
 
 def mutupdval(expr):
-    pos = randint(0, len(expr) - 1)
+    if len(expr) == 1:
+        pos = 0
+    else:
+        pos = randint(0, len(expr) - 1)
     if expr[pos].optype == RpnSymbol.VALUE:
         expr[pos] = RpnSymbol.rand_value()
     else: