Editing Declarative programming (section)

===ML===
[[ML (programming language)|ML]] (1973)<ref name="Gordon1996">{{cite web
 | last = Gordon
 | first = Michael J. C.
 | author-link = Michael J. C. Gordon
 | year = 1996
 | title = From LCF to HOL: a short history
 | url = http://www.cl.cam.ac.uk/~mjcg/papers/HolHistory.html
 | access-date = 2021-10-30
 | archive-date = 2016-09-05
 | archive-url = https://web.archive.org/web/20160905201847/http://www.cl.cam.ac.uk/~mjcg/papers/HolHistory.html
 | url-status = live
 }}</ref> stands for "Meta Language." ML is statically typed, and function arguments and return types may be annotated.<ref name="cpl_3rd-ch9-233">{{cite book
  | last = Wilson
  | first = Leslie B.
  | title = Comparative Programming Languages, Third Edition
  | publisher = Addison-Wesley
  | year = 2001
  | page = 233
  | isbn = 0-201-71012-9
}}</ref> 

{{sxhl|2=sml|1=fun times_10(n : int) : int = 10 * n;}}

''ML'' is not as bracket-centric as ''Lisp'', and instead uses a wider variety of syntax to codify the relationship between code elements, rather than appealing to list ordering and nesting to express everything. The following is an application of <code>times_10</code>:

 times_10 2

It returns "20 : int", that is, <code>20</code>, a value of type <code>int</code>. 

Like ''Lisp'', ''ML'' is tailored to process lists, though all elements of a list must be the same type.<ref name="cpl_3rd-ch9-235">{{cite book
  | last = Wilson
  | first = Leslie B.
  | title = Comparative Programming Languages, Third Edition
  | publisher = Addison-Wesley
  | year = 2001
  | page = 235
  | isbn = 0-201-71012-9
}}</ref>