SML# Document Version 4.2.0

24 Module language declarations and interface 24.3 Signature expression :

\,\langle

\rangle\,

25 Overview of SML# Libraries

24.4 Module language interface

As defined in Section 16.2, module language interface consists of t provides for structures ( $\,\langle$ provideStr $\rangle\,$ ) and for functors ( $\,\langle$ provideFun $\rangle\,$ ), whose syntax is given below.

$\,\langle$ provideStr $\rangle\,$	::=	structure $\,\langle$ strid $\rangle\,$ = struct $\,\langle$ provideStrdecl $\rangle\,$ end
$\,\langle$ provideStrdecl $\rangle\,$	::=	$\,\langle$ provideVal $\rangle\,$
	$\|$	$\,\langle$ provideType $\rangle\,$
	$\|$	$\,\langle$ provideDatatype $\rangle\,$
	$\|$	$\,\langle$ provideException $\rangle\,$
	$\|$	$\,\langle$ provideStr $\rangle\,$
$\,\langle$ provideFun $\rangle\,$	::=	functor $\,\langle$ provideFunBind $\rangle\,$
$\,\langle$ provideFunBind $\rangle\,$	::=	$\,\langle$ funid $\rangle\,$ ( $\,\langle$ strdesc $\rangle\,$ ) = $\,\langle$ provideStrExp $\rangle\,$

The following are examples of structure declarations and their interface.

Bool.sml file: structure Bool =
struct
  datatype bool = false | true
  fun not true = false
    | not false = true
  fun toString true = "true"
    | toString false = "false"
end Bool.smi file: structure Bool =
struct
  datatype bool = false | true
  val not : bool -> bool
  val toString : bool -> string
end