ocaml

I need an array-like data structure with the fastest possible functional update. I've seen a few different implementation of flexible arrays that provide me with this property (Braun, Random Access Lists) but I'm wondering if there is an implementation that is specifically optimized for the case when we are not interested in append or prepend - just updates. Jean-Cristophe Filliâtre has a very nice implementation of persistent arrays, that is described in the paper linked at the same page (which is about persistent union-find, of which persistent arrays are a core component). The code is

I have a task to write a (toy) parser for a (toy) grammar using OCaml and not sure how to start (and proceed with) this problem. Here's a sample Awk grammar: type ('nonterm, 'term) symbol = N of 'nonterm | T of 'term;; type awksub_nonterminals = Expr | Term | Lvalue | Incrop | Binop | Num;; let awksub_grammar = (Expr, function | Expr -> [[N Term; N Binop; N Expr]; [N Term]] | Term -> [[N Num]; [N Lvalue]; [N Incrop; N Lvalue]; [N Lvalue; N Incrop]; [T"("; N Expr; T")"]] | Lvalue -> [[T"$"; N Expr]] | Incrop -> [[T"++"]; [T"--"]] | Binop -> [[T"+"]; [T"-"]] | Num -> [[T"0"]; [T"1"]; [T"2"]; [T

I'm trying to write topological sorting in ocaml, but I'm a beginner (in OCaml & graphs algorithms) and I can't do this by myself. It's easier for me to think about topological sorting in, for example, C++ (and there is a lot examples of topological sorting in C++ on the Internet), but I want to learn something new. Moreover, I've found some examples of topological sorting written in OCaml, but I don't understand them, to be frankly. Let's say I have a list (int * int list) list , for example: myList = [(1, [2]); (5, [6; 7]); (3, [2]); (6, [3; 7]); (8, [7]); (4, [3; 1])];; and that means, that

I defined a custom equality operator (the definition is not really important so I will insert dummy stuff): let ( ~=~ ) a b = true If I try to use it infix: if a ~=~ b then 1 else 2 I get the following error: This expression is not a function; it cannot be applied . I can fix this either by renaming the operator from ~=~ to =~ or by calling it as a function: if (~=~) a b then 1 else 2 . This seems that is a general problem with operators that start with ~ . My question is why I can't use such operators infix? Is anything special about ~ symbol? Note: I already went through documentation but I

Can the following polymorphic functions let id x = x;; let compose f g x = f (g x);; let rec fix f = f (fix f);; (*laziness aside*) be written for types/type constructors or modules/functors? I tried type 'x id = Id of 'x;; type 'f 'g 'x compose = Compose of ('f ('g 'x));; type 'f fix = Fix of ('f (Fix 'f));; for types but it doesn't work. Here's a Haskell version for types: data Id x = Id x data Compose f g x = Compose (f (g x)) data Fix f = Fix (f (Fix f)) -- examples: l = Compose [Just 'a'] :: Compose [] Maybe Char type Natural = Fix Maybe -- natural numbers are fixpoint of Maybe n = Fix

Know of an OCAML/CAML IDE? Especially one that runs on Linux? Alex M Emacs in Caml mode , or Tuareg mode , or TypeRex mode . TypeRex adds auto-completion to Taureg in emacs - a really nice feature for people who prefer the more graphical IDE's. There is Camelia . You can also integrate OCaml into Eclipse . Also in Emacs you can use ocaml-mode and tuareg-mode. NullPointer I vote OcaIDE . Now it has upgraded to v1.2.5. it become an up-to-date IDE (supporting ocaml 3.10-3.11, especially ocamlbuild, which is a great time-saver) and armed with rich, stable features. I've installed OcaIDE on an

One of the huge benefits in languages that have some sort of reflection/introspecition is that objects can be automatically constructed from a variety of sources. For example, in Java I can use the same objects for persisting to a db (with Hibernate), serializing to XML (with JAXB), and serializing to JSON (json-lib). You can do the same in Ruby and Python also usually following some simple rules for properties or annotations for Java. Thus I don't need lots "Domain Transfer Objects". I can concentrate on the domain I am working in. It seems in very strict FP like Haskell and Ocaml this is not