Poly.PolV
Polynomial variables are collected in a module of type Symb.NAME
.
val symb_list : unit -> t list
symb_list ()
is the list of all names registered up to calling this function.
val get_symb : string -> t
get_symb name
returns the symbol registered with name
.
val get_symb_opt : string -> t option
get_symb_opt name
is Some t
if there is a symbol t
registered with name
, None
otherwise.
val register_name : string -> t
register_name name
is the name (of type t
) registered with key name
. If there is already a name registered with this key, then register_name name
returns the already registered name associated with this key. This behavior make this module behave as a 'set-like' structure.
val to_string : t -> string
to_string name
is the string representation of the name name
.
Note: a standard implementation of to_string
would return the same string used as key for registering name
. Hence, satisfying to_string (get_symb (register_name "n"))
equals "n"
. This property is not enforced, however. It is up to implementers the choice of how to write names back to string format.
compare x y
returns 0
if x
is equal to y
, a negative integer if x
is less than y
, and a positive integer if x
is greater than y
.
Note: compare
enforces a total order over the type t
.