O'Caml

1
O'Caml

• COSC 4153
• Spring 2008
• Assignment 11
• Brent Bradbury

2
Overview

• Brief history
• Syntax and semantics
• Uses of the language
• Advantages and disadvantages
• Likes and dislikes
• Conclusion
• Sources

3
Brief History

• Caml was originally an acronym for Categorical
  Abstract Machine Language.
• First made by INRIA, a French CS research program
• Guy Cousineau made CAML in 1987
• Xavier Leroy and Damien Doligez followed in '91
  and '92 with CAML Light
• Xavier Leroy released CAML Special Light in 1995,
  adding a native compiler and module system

4
And finally,

• O'Caml added support for object-oriented
  functional programming in 1996
• O'Caml combines standard object-oriented
  techniques with the static typing and type
  inference of ML

5
Basic Syntax and Semantics
( main.ml)? open ChemParse open Lexer let
_ try let lexbuf Lexing.from_channel
stdin in while true do
let result ChemParse.input Lexer.token lexbuf
in print_endline result
flush stdout done with Lexer.Eof -gt
exit 0
6
More Syntax and Semantics
let rec add x y if y 0 then x else
(add x (y - 1)) 1 let rec mult x y
if y 0 then 0 else let z (mult x (y - 1))
in add x z

• Recursive functions must be explicitly defined,
  otherwise their name is outside their internal
  scope
• Types are not implicitly coerced. Operators,
  since they are also considered functions, must
  work on appropriate types.

Integer operators
Float operators

let average a b (a . b) /. 2.0
let average a b (a b) / 2
7
Uses of the Language

• Almost entirely used in academia
• Can substitute for Matlab in some applications
• Has hooks into many useful libraries (LAPACK,
  OpenGL, GTK, etc.)?
• Still isn't very practical for large applications
• A few small companies use O'Caml, but no one
  significant

8
Advantages and Disadvantages

• Advantages
• Algorithm development is fast
• It can be compiled, and runs quickly
• Doesn't stay so functional that it can't be made
  practical
• Disadvantages
• It's obscure
• It lacks infrastructure for proper software
  engineering
• The syntax is unintuitive and hard to learn

9
Likes and Dislikes

• Likes
• Algorithms are concise
• I feel really smart whenever I make anything work
• Objects are useful and grant good flexibility.
• Dislikes
• The syntax is annoying
• Doing everything functionally is frustrating
• Static typing is frustrating, mostly.

10
Conclusion

• O'Caml is not very useful
• It's a good academic exercise, though
• I plan to write an IUPAC alkane name to NMR
  Spectroscopy parser with complete unit tests,
  because I have to for a job interview
• I'm using ocamlyacc and ocamllex to do the
  parsing
• I'm using OUnit for unit testing

11
Sources

• http//www.ocaml-tutorial.org
• http//caml.inria.fr/about/history.en.html
• http//wiki.cocan.org/people/north_america