update Primitive of 'square root' block

1 files changed, 16 insertions, 0 deletions

diff --git a/TurtleArt/talogo.py b/TurtleArt/talogo.py
index 7480ab9..35fe04a 100644
--- a/TurtleArt/talogo.py
+++ b/TurtleArt/talogo.py
@@ -83,6 +83,20 @@ class logoerror(Exception):
         return str(self.value)
 
 
+class NegativeRootError(BaseException):
+    """ Similar to the ZeroDivisionError, this error is raised at runtime
+    when trying to computer the square root of a negative number. """
+
+    DEFAULT_MESSAGE = 'square root of negative number'
+
+    def __init__(self, neg_value=None, message=DEFAULT_MESSAGE):
+        self.neg_value = neg_value
+        self.message = message
+
+    def __str__(self):
+        return str(self.message)
+
+
 class HiddenBlock(Block):
 
     def __init__(self, name, value=None):
@@ -543,6 +557,8 @@ class LogoCode:
                                     _("as input")))
                             except ZeroDivisionError:
                                 raise logoerror("#zerodivide")
+                            except NegativeRootError:
+                                raise logoerror("#negroot")
                         else:
                             try:
                                 self.step.next()