| SAXONICA | 
Function signature
| $function | xs:string | 
| Result | xs:boolean | 
Determines whether a function with a given name (regardless of arity) is available in the context
Function signature
| $function | xs:string | 
| $arity | xs:integer | 
| Result | xs:boolean | 
Determines whether a function with the given name and arity is available in the context.