2.3 Spaces after parentheses ¶

When writing routine texts always place a space between the formal parameters pack and the mode of the value yielded by the routine.

When writing operator and procedure declarators do not put a space between the parameter modes pack and the mode of the yielded value.

Also in declarers, do not put a space after op or proc and the parameter modes pack.

{ Space after formal parameters pack in routine text }
json_foreach_elem(a, (ref JSON_Val v) void: len +:= 1)

{ No space after parameters pack in procedure and operator
  declarators }
proc(string)void error;