Symbolic has_operator()

[rwst]

A convenience function in addition to has would not need a wildcard to test for existence of specific operators or functions in an expression. More urgently it is not possible to test for the existence of eg symbolic_sum operators without giving a specific variable.

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/22926

[rwst]

Description changed:

--- 
+++ 
@@ -1,2 +1,2 @@
-A convenience function in addition to `has` would not need a wildcard to test for existence of specific operators or functions in an expression, but needs support from Pynac.
+A convenience function in addition to `has` would not need a wildcard to test for existence of specific operators or functions in an expression, but needs support from Pynac. More urgently it is not possible to test for the existence of eg symbolic_sum operators without giving a specific variable.
 

[rwst]

Description changed:

--- 
+++ 
@@ -1,2 +1,2 @@
-A convenience function in addition to `has` would not need a wildcard to test for existence of specific operators or functions in an expression, but needs support from Pynac. More urgently it is not possible to test for the existence of eg symbolic_sum operators without giving a specific variable.
+A convenience function in addition to `has` would not need a wildcard to test for existence of specific operators or functions in an expression. More urgently it is not possible to test for the existence of eg symbolic_sum operators without giving a specific variable.