I've been thinking about how type inference works in the following OCaml program: let rec f x = (g x) + 5 and g x = f (x + 5);; Granted, the program is quite useless (looping forever), but what about the types? OCaml says: val f : int -> int = <fun> val g : int -> int = <fun> This would exactly be my intuition, but how does the typ...
I'm trying to define an exception in OCaml that accepts a tuple pair of lists as an argument. However, this situation doesn't work? # exception Foo of string list * string list;; exception Foo of string list * string list # let bar = (["a"], ["b"; "c"; "d"]);; val bar : string list * string list = (["a"], ["b"; "c"; "d"]) # raise(Foo b...
This isn't a homework question, by the way. It got brought up in class but my teacher couldn't think of any. Thanks. ...
I am trying to convert a given decimal value its corresponding binary form. I am using Ocaml about which I don't know much and am quite confused. So far I have the following code let dec_to_bin_helper function 1->'T' | 0->'F' let dec_to_bin x = List.fold_left(fun a z -> z mod 2 dec_to_bin_helper a) [] a ;; I must include h...
I've taken the following code from http://www.ocaml-tutorial.org/data_types_and_matching I've been trying to write a C stub for following, to invoke from our PHP codebase. I can't quite understand how (and if) I'm supposed to create a typedef for the following Ocaml type expr, and how I can access the function multiply_out from the C st...
Hi everyone, I am attempting to enumerate the set of all pairs made of elements from two lazy lists (first element from the first list, second element from the second list) in OCaml using the usual diagonalization idea. The idea is, in strict evaluation terms, something like enum [0;1;2;...] [0;1;2;...] = [(0,0);(0,1);(1;0);(0;2);(1;1)...
Hi, When working in the ocaml or ghci toplevels I often build up a significant "context" for want of a better word, values bound, functions, modules loaded, and so on. Is there a way to save all of that and reload it later so I can continue exactly where I left off? Or better yet, dump out the entire lot as a text file that could be rel...
Hi guys, As part of a bigger problem of enumerating a set, I need to write an OCaml function 'choose' which takes a list and outputs as the list of all possible sequences of size k made up of elements of that list (without repeating sequences which can be obtained from each other by permutation). The order they are put in the end list i...
I'm trying to make a function which drops the first n items of a list: let rec drop n h = if n == 0 then h else (drop n-1 (match h with a::b -> b));; This is giving: Characters 43-49: if n == 0 then h else (drop n-1 (match h with a::b -> b));; ^^^^^^ Error: This expression has type 'a -> 'b but is here...
The prototype must be: listMinPos(lst) I'm able to write the same using two arguments, (list and index), but am not able to even think how it can be possible using only the list argument. The following must hold: only 1 argument (the list). no external libraries. function should be recursive (no 'let' inside the function) ...
As everybody knows, Ocaml lets to use various modules: List, Map, Nativeint, etc. I know, that interfaces for these modules are provided (e.g. for List module: http://caml.inria.fr/pub/docs/manual-ocaml/libref/List.html), but I am interested in algorithms (= implementation = code) used in modules' functions. So - where can I find that? ...
In my C# application, I'm firing up a program using the .NET Process class. Sometimes, after the program has finished, the Process.ExitCode is -1. It's a large program, and I'm having trouble tracking down where `exit' is called with -1. In fact, I don't see how it's possible to have a program return an exit code of -1. I've created ...
I'm trying to make a recursive function to get the transpose of a list of lists, n x p to p x n. But i'm unable to do so. I've been able to make a function to transpose a 3 x n list of lists to an n x 3 one: let rec drop1 list= [(match (List.nth list 0) with [] -> [] | a::b -> b); (match (List.nth list 1) with [] -> [] | a::b -...
I wrote a code: let rec compareVs v1 v2 = if List.length v1 == 0 then true else ((match v1 with [] -> 0. | h::l -> h) == (match v2 with [] -> 0. | h::l -> h)) && (compareVs(match v1 with [] -> [] | h::l -> l) (match v2 with [] -> [] | h::l -> l)) And ran it: # compareVs [0.1;0.1] [0.1;0.1];; - : bool = false Can't seem to ...
What I'm doing: I'm writing a small interpreter system that can parse a file, turn it into a sequence of operations, and then feed thousands of data sets into that sequence to extract some final value from each. A compiled interpreter consists of a list of pure functions that take two arguments: a data set, and an execution context. Each...
Hello, I'm interested in learning this language, but it seems that there is very few tutorials and books on the subject. I've found only one suitable book on the subject (Developing Applications With Objective Caml) which would be absolutely perfect but the problem is that it is based on version 2.04. So my only concern is if there wou...
Running Swig example for ocaml gives me this error message. rm -rf swig.mli swig.ml swigp4.ml "'" ; "[" ; e2 = expr ; "]" -> Line 27: > ... Line 114: | f = expr ; "'" ; "(" ; args = LIST0 (expr LEVEL "simple") SEP "," ; ")" -> Line 115: > Line 116: ] ] ; Line 117: END ;; What might be wrong? How to install grammar m...
Hi Guys, I have a very basic question regarding OCaml records. Suppose I have a record defined: type r = {a:int;b:int;c:int} let x = {a=3;b=8;c=2} Now, suppose I want to create a new record which has all fields equal to x but which has c=4. I could write: let y = {a=3;b=8;c=4} but this is annoying because there's not need to re-wr...
I am working on a module which involves a set of natural numbers. As a result I need to model some n of type integer. How can I go about it? Eg. sum of i for continuously increasing sequence of i starting at 1 = n(n+1)/2 How can I model n here? ...
I am using emacs with tuareg mode and I always have the ocaml repl opened inside emacs. I was wondering if there's a way of compiling basic OCaml test files from within the repl so I don't have to run the compilation as a system command. ...