gmane.comp.lang.ocaml.beginners

Any tool for unit tests as comments in OCaml source?

Francois Berenger — 2012-05-15T01:48:35

Hello,

What's the gold standard in OCaml to have
unit test as comments in source code in order
for a tool to automatically extract them
and generate a test suite?

Thanks,
F.

C Interface, Libraries, and Books?

jr — 2012-05-13T16:27:42

I've just started to dig into OCaml, and so far I like it.  By way of
background, I've done a fair amount of Haskell programming (for my own
purposes, not for distribution), as well as a lot of Prolog, and a few dips
into Scheme.  For many many years I was a Linux, Unix, and Cygwin user, but
for the past four years I've been using OS X.

Please forgive some obvious questions -- I'd like to know if I can get
where I want to go before I go too far.

1. Is there a straightforward, documented way to produce a library callable
from C?   Where is it documented?  One of my goals is to write Mac OS X
applications using XCode where in the Model-View-Controller pattern, the
Model and perhaps some aspects of Controller are in a functional language
(or mostly functional with some mutability), and the user interface is pure
Cocoa.

2. How about standard libraries?  Does "Batteries" compile on OS X Lion
(how about upcoming Mountain Lion)?  If so should I get it?  I'm
interested (at the moment) in Sets, Graphs, and Parsers (like Haskell's
Parsec).  I see that there are a number of packages out there that emulate
Parsec.  Is one 'standard'? 

3. Is there a decent physical book available (in English), or shall I wait
for "Real World Caml" by Hickey et al? I prefer a real physical book for
learning; eBook, PDF or HTML are OK for reference. I'm  using Jason
Hickey's PDF book "Introduction to Objective Caml" as well as other
available tutorial material for now.

That's all for now.  Questions 1. and 2. are particularly important.
Haskell has libraries, but -- when I tried -- it was too much trouble to
put anything into a library accessable from XCode (maybe it's better now,
but I haven't kept up with my Haskell for a few years).  Gambit Scheme
seemed to have the ability to produce C libraries, but the application
library situation was pretty hopeless.  It seemed that if I wanted to use
Scheme I'd have to write a lot of my own basic tools.

Thanks,

John Velman

polymorphism broken with mutable variables ?

san.vu-ngoc — 2012-05-11T12:34:49

Hi

I'm curious:
the following functions have a different type: why ?

# let a = 1 in fun f -> f a;;
- : (int -> 'a) -> 'a = 

# let a = ref 1 in fun f -> f !a;;
- : (int -> '_a) -> '_a = 

Sorry if this is a FAQ.

San



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Just another of these basic things ...

Michael Erdmann — 2012-05-09T05:07:38

Hallo,

there is another of these issues i need to get used to:

Works :
# List.length(x);;
- : int = 1
#

so i expected the following to work; but i got:

# print_int List.length(x);;
  print_int List.length(x);;
Error: This function is applied to too many arguments;
maybe you forgot a `;'

what finally works

# List.length(x);;
- : int = 1
# print_int (List.length x);;
1- : unit = ()
#

seems that print_int List.length(x) is read by like

print_int  List.length   (x) 

meaning print_int gets two arguments; correct?

Woudn't it be better in the first case to issue an warning that there
should
be at least a blank like List.length (x).

This seems to be completely different in  comparison to other languages
like
Ada; Java and requires some time to get used to it :-)))



/Michael

Setting up donations for OASIS and odb.ml

Francois Berenger — 2012-05-09T02:13:52

Hello,

How about setting up a donate button to each of these projects?

I would personally like to give some of my pocket money to both of these
projects and I am sure I am not the only one in this situation.
Also, these two projects look very important for a wider adoption of OCaml.

Regards,
F.

PS: maybe ocamlbrew too?

Proably an FAQ but how to get around the problem

Michael Erdmann — 2012-05-06T07:52:10

Hallo *,

i guess i have a simple problem, i found a solution but i am not
convinced that this is a
correct Ocaml solution.

The code fragment at the end of the e-mail is part an excerpt of an
interpreter i am
writing for training. The function execute_command takes a command as input
and executes the corresponding command. There is one command called
batch which
allows to execute complete files by reading them line by line and again
executing the
function execute_command. This simply does not compile since execute_command
is unbound in the execute_file function :-((

My current solution is to pass a function to execute_file as argument 
which is called
instead of calling execute_command directly.

let execute_file chan interp = .....
    let cmd = input_line chan in *interp *cmd;     
;;

let *execute_command* cmd args=
        | "batch" -> let chan = open_in args in execute_file chan
execute_command
 
;;

It works; but is this really the best solution ..... ?????

Advise is highly welcome :-)))

/Michael


...................................................
(** some command *)
let do_go args =
    print_endline "go ..."
;;

(** read in a batch of commands from a file *)
let execute_file chan =
    try    
        while true do       
           begin            
             let cmd = input_line chan in *execute_command*(cmd);        
          end
        done
    with x ->
      print_endline "done ****";                
;;   

(** execute a single commmand line *)
let *execute_command* cmd args=
    match cmd with
            "go" -> do_go(args)
        | "batch" -> let chan = open_in args in execute_file chan
        | _ -> print_endline "wrong command"
;;

(** toplevel *)



[Non-text portions of this message have been removed]

ocaml video tutorial

sayanta_mallick — 2012-04-26T12:47:42

Dear Caml Expert,

Is any good website where I can find video or e-learning tutorial on Ocaml.

Thanks in advance 

Babai

convert string into list of list of characters

narcoleptic1984 — 2012-04-21T16:05:44

Hi!
I've just started taking Ocaml classes and I have assignment.
A part of it is to make a functtion which will convert string into list of list of characters.
example:

if input is: " pro blem" the output should be: [['p';'r';'o']['b';'l';'e';'m']]
i know how to write function to convert string to list of characters, but i have no idea how to insert new variable (niz.[a]) which would create new list when it hits a blank char. 

this is what i'e done so far:

let explode niz =
  let rec exp a b =
    if a < 0 then b 
    else exp (a - 1) (niz.[a]::b) in
  exp (String.length niz - 1) []
     ;;

Kendall tau in OCaml

Francois Berenger — 2012-04-20T02:51:05

Hello,

Is there some Kendall tau implementation out there in OCaml?

I'm looking for something with better complexity than N^2, if
that's possible, as I have a lot of points...

Regards,
F.

installing tuareg mode on win7 emacs

cgnormandin — 2012-04-18T02:45:56

What a friggin PITA!!

I'm a *nix person, so most of this is MY fault for having these problems.

Anyway, I've got package.el installed. I think I've got this "marmalade" thingy working. So how do I install "tuareg-mode"?

M-x package-install is NOT doing it for me. So I hope that Christophe Troestler is tuning in. :)

cyclic types

Vu Ngoc San — 2012-04-17T14:34:44

Hi

I have a basic question on cyclic types. Sorry if it has already been 
answered here, I couldn't find it.

the following is valid

type t = { value: int; next : t };;
let rec a = {value=1; next =b} and b = {value = 2;  next=a};;

Thus a and b form a cyclic graph with two elements.

In my situation the records are results of some functions, say

let make1 a = {value=1; next=a};;
let make2 a = {value=2; next=a};;

the following is not accepted:

let aa = make1 bb and bb = make2 aa;;

Error: Unbound value bb

what is the best way to write it ?

Thanks
San

Is OCAML still being developed at INRIA?

duke normandin — 2012-04-17T03:11:02

Hi ...
I stumbled on an article on the Web a day or so ago, that suggested that INRIA was abandoning OCAML as a research project. Does anyone know if this is true or not? TIA ...

--
Duke

installing library with alternate names using oasis

Ashish Agarwal — 2012-04-15T16:33:00

Is there a way with Oasis to modify the name a library is installed with.
For example, I would like to define a configure option like
"--with-version", which will install my library with the name "foo-v1"
instead of just "foo". (Extra points if you also know how to use the value
of the Version field in the name.)

The reason I need this is that my code depends on a database. When I
upgrade my code from v1 to v2, I need to write a migration script that will
depend on both versions of the library, so I need multiple versions
installed at the same time. If there's a better way to handle this, I'd be
happy to get your suggestions.


[Non-text portions of this message have been removed]

Loading code into toplevel

Boris Hollas — 2012-04-13T10:03:02

Hello,

I have code that uses a number of modules from a third-party library and
I want to load the former into the toplevel system for debugging
purposes. Trying to do so results in an error message

Error: Unbound module Cil_types

There is a file cil_types.cmi in /usr/local/lib/frama-c/, but no
corresponding .cmo file. I can compile the code with a makefile provided
for Frama-C though. Is this a problem with the build process or is there
another problem?

Hard time figuring out how to use format parameter

2012-04-11T05:01:10

I'm trying to code a custom printer that, instead of returning
the string, returns a function to return the string:

# let p fmt x = Printf.sprintf fmt x;;
val p : ('a -> 'b, unit, string) format -> 'a -> 'b = <fun>
# p "%a" (fun _ x -> Printf.sprintf "%d" x) 15;;
- : string = "15"
# let p fmt x = lazy (Printf.sprintf fmt x);;
val p : ('a -> 'b, unit, string) format -> 'a -> 'b lazy_t = <fun>
# p "%a" (fun _ x -> Printf.sprintf "%d" x) 15;;
Error: This function is applied to too many arguments; maybe you forgot a `;'
# p "%d" 15;;
- : string lazy_t = <lazy>

No more luck replacing the lazy by a fun:

# let p fmt x = (fun () -> Printf.sprintf fmt x);;
val p : ('a -> 'b, unit, string) format -> 'a -> unit -> 'b = <fun>
# let f = p "%d" 42;;
val f : unit -> string = <fun>
# f ();;
- : string = "42"
# let f = p "%a" (fun _ d -> Printf.sprintf "%d" d) 42;;
Error: This expression has type int but an expression was expected of type unit

In the presence of the fun (or lazy), the typer seams to infer that x is
a 'normal', single parameter, instead of the expected 'magical' format parameter.
It does so as soon as there are more than one argument to the format.
For instance, this fails as well:

# let f = p "%d %d" 42 43;;
Error: This expression has type int but an expression was expected of type unit

Is there a way around this?
BTW, I couldn't find much documentation about format and its parameters. Most
of the doc I can find explain how to use format but ot how it works, including
the manual it seams :-(
Is there an obvious source of information I missed?

Library for distribution and/or histogram and cumulative distribution

Johan Mazel — 2012-04-04T14:54:01

Hello
I would like to know whether there is any available library to handle
empirical distribution/histogram and cumulative distribution.
I think it can be done through R bindings.
I was wondering if there a library that could do the job in a simpler
way (i.e. not through an interpreter or my own bindings). OCaml GSL
seems to have several kind of distribution but none on empirical data.
Regards.
Johan

functors and separate files

Vu Ngoc San — 2012-04-02T15:18:09

Hello

I would like to split my functors into separate files. The manual tells me

"Notice that only top-level structures can be mapped to 
separately-compiled files, but not functors nor module types. However, 
all module-class objects can appear as components of a structure, so the 
solution is to put the functor or module type inside a structure, which 
can then be mapped to a file."

Could you tell me, concretely, what is the "solution" proposed here ?

thanks
San

fatal error: unknown C primitive caml_expm1_float in CentOS 5.8

Jean Saint-Remy — 2012-04-01T02:42:37

Bonjour Mon Ami,

I have been trying to build ocaml 3.12.1 on CentOS 5.8 running 32 bit kernel 2.6.18-308.1.1.el5
with GCC 4.1.2 20080704 (Red Had 4.1.2-52). The configure and the build works like a charm, 

without any errors as far as I can tell. I am using the 'make world.opt' kitchen-sink command. I have 

seen this error only with Red Hat, because I have built 3.12.1 with Debian, and Ubuntu derivatives
without a hitch using the same Intel 32-bit Centrino architecture with later versions of GCC like 4.3
or 4.4. When I try to run any ocaml program from CLI (which loads with #!/usr/bin/ocamlrun ocaml)
I get this error "Fatal error: unkown C primitive caml_expm1_float." I believe that I am missing 

something in the environment, because I can successfully load the same programs in the top
level. I tried running a strace on the process, but have been only able to determine that some low
level library is not loading correctly, but not sure which one. The caml_expm1_float is defined in
the Pervasives module, but duno where the C culprit comes from. I could abandon Red Hat, but 

I cannot abandon ocaml. Any suggestion will be kindly appreciated.


With kind regards,

Jean

parenthesis when it is a pair

Kim Quyen Ly — 2012-03-29T04:42:42

Hello,

I have this product type, and I want to enclose it by parenthesis when it is a pair. 

For example:

test = t1 * t2 * t3 * t4

- output:

test = (((t1 * t2) * t3) * t4)

I want to write this function by recursion the list l 
 
let rec par l =
   let len = List.length l in
    (*if len is = 2 then I will put the parenthesis*)
     ???

monads in OCaml

Francois Berenger — 2012-03-29T01:16:16

Hello,

Is there some code recommended to read in order to understand
and get used to monads in OCaml?

For example, some bunch of code using options extensively.

Thanks a lot,
F.

example using the Format module

eugen_zalinescu — 2012-03-28T09:31:45

At the "Using the Format module" mini-guide (http://caml.inria.fr/resources/doc/guides/format.en.html), there is a concrete example on pretty-printing lambda expressions, in 3 versions. The second version (see "Using printf" subsection) does not seem to work. I get the following type-checking error:

Error: This pattern matches values of type lambda
       but a pattern was expected which matches values of type
       Format.formatter

What is the simplest way to fix it?