Fix asy output for compabitibility with the doc generator. In , catch possible fail in os.getlogin()

Author: mmatera

mathics/builtin/graphics.py

@@ -3194,7 +3194,7 @@ def boxes_to_tex(self, leaves, forxml=False, **options):
         if forxml:
             return (tex, width, height)
         else:
-            return "\n\\begin{asy}\n" + tex + "\n\\end{asy}"
+            return "\n\\begin{asy}\n" + tex + "\n\\end{asy}\n"
 
     def boxes_to_xml(self, leaves, **options):
         evaluation = options.get("evaluation", None)

mathics/builtin/system.py

@@ -406,8 +406,16 @@ class UserName(Predefined):
 
     name = "$UserName"
 
+    messages = {
+        'nologin': "UserName not available in this system.",
+    }
+
     def evaluate(self, evaluation) -> String:
-        return String(os.getlogin())
+        try:
+            return String(os.getlogin())
+        except:
+            evaluation.message('$UserName', 'nologin')
+            return
 
 
 class Version(Predefined):