1\DOC op_arity
2
3\TYPE {op_arity : {Thy:string, Tyop:string} -> int option}
4
5\SYNOPSIS
6Return the arity of a type operator.
7
8\KEYWORDS
9signature, type operator.
10
11\DESCRIBE
12An invocation {op_arity{Tyop,Thy}} returns {NONE} if the given record
13does not identify a type operator in the current type signature.
14Otherwise, it returns {SOME n}, where {n} identifies the number
15of arguments the specified type operator takes.
16
17\FAILURE
18Never fails.
19
20\EXAMPLE
21{
22- op_arity{Tyop="fun", Thy="min"};
23> val it = SOME 2 : int option
24
25- op_arity{Tyop="foo", Thy="min"};
26> val it = NONE : int option
27}
28
29
30\SEEALSO
31Type.decls.
32\ENDDOC
33