Here are listed a few functions which convey information about expressions and other macro functions.
string type (any)
Returns the type of an expression as a string.
list arguments ()
Returns the list of the arguments with which the current function was called. Used to retrieve the arguments passed to functions which are declared without an argument list and to retrieve arguments passed to a macro program run in batch mode.
none describe ( string )
Prints a terse one-line description of the function whose name is passed as the argument.
list dictionary ()
Returns a list of all the available functions.