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Search found 97 results on 4 pages for 'ocaml'.

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  • Are there any purely functional Schemes or Lisps?

    - by nickname
    Over the past few months, I've put a lot of effort into learning (or attempting to learn) several functional programming languages. I really like math, so they have been very natural for me to use. Simply to be more specific, I have tried Common Lisp, Scheme, Haskell, OCaml, and (a little bit of) Erlang. I did not like the syntax of OCaml and do not have enough Erlang knowledge to make a judgment on it yet. Because of its consistent and beautiful (non-)syntax, I really like Scheme. However, I really do appreciate the stateless nature of purely functional programming languages such as Haskell. Haskell looks very interesting, but the amount of inconsistent and non-extendable syntax really bothered me. In the interest of preventing a Lisp vs Haskell flame war, just pretend that I can't use Haskell for some other reason. Therefore, my question is: Are there any purely functional Schemes (or Lisps in general)?

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  • generic programming- where did it originate?

    - by user997112
    Im trying to work out if generic programming was a functional programming feature which was then introduced into Java, C++ and C# or did the latter copy it from the functional programming languages like Haskell, Lisp, OCaml etc? Google is giving me lots on what generic programming is, but not where it originated. All I can see is that Ada implemented it early on. Would you class it as a functional programming technique?

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  • Is there an alternative to Google Code Search?

    - by blunders
    Per the Official Google Blog: Code Search, which was designed to help people search for open source code all over the web, will be shut down along with the Code Search API on January 15, 2012. Google Code Search is now gone, and since that makes it much harder to understand the features it presented, here's my attempt to render them via information I gathered from a cache of the page for the Search Options: The "In Search Box" just notes the syntax to type the command directly in the main search box instead of using the advance search interface. Package (In Search Box: "package:linux-2.6") Language (In Search Box: "lang:c++") (OPTIONS: any language, actionscript, ada, applescript, asp, assembly, autoconf, automake, awk, basic, bat, c, c#, c++, caja, cobol, coldfusion, configure, css, d, eiffel, erlang, fortran, go, haskell, inform, java, java, javascript, jsp, lex, limbo, lisp, lolcode, lua, m4, makefile, maple, mathematica, matlab, messagecatalog, modula2, modula3, objectivec, ocaml, pascal, perl, php, pod, prolog, proto, python, python, r, rebol, ruby, sas, scheme, scilab, sgml, shell, smalltalk, sml, sql, svg, tcl, tex, texinfo, troff, verilog, vhdl, vim, xslt, xul, yacc) File (In Search Box: "file:^.*.java$") Class (In Search Box: "class:HashMap") Function (In Search Box: "function:toString") License (In Search Box: "license:mozilla") (OPTIONS: null/any-license, aladdin/Aladdin-Public-License, artistic/Artistic-License, apache/Apache-License, apple/Apple-Public-Source-License, bsd/BSD-License, cpl/Common-Public-License, epl/Eclipse-Public-License, agpl/GNU-Affero-General-Public-License, gpl/GNU-General-Public-License, lgpl/GNU-Lesser-General-Public-License, disclaimer/Historical-Permission-Notice-and-Disclaimer, ibm/IBM-Public-License, lucent/Lucent-Public-License, mit/MIT-License, mozilla/Mozilla-Public-License, nasa/NASA-Open-Source-Agreement, python/Python-Software-Foundation-License, qpl/Q-Public-License, sleepycat/Sleepycat-License, zope/Zope-Public-License) Case Sensitive (In Search Box: "case:no") (OPTIONS: yes, no) Also of use in understanding the search tool would be the still live FAQs page for Google Code Search. Is there any code search engine that would fully replace Google Code Search's features?

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  • Unit testing statically typed functional code

    - by back2dos
    I wanted to ask you people, in which cases it makes sense to unit test statically typed functional code, as written in haskell, scala, ocaml, nemerle, f# or haXe (the last is what I am really interested in, but I wanted to tap into the knowledge of the bigger communities). I ask this because from my understanding: One aspect of unit tests is to have the specs in runnable form. However when employing a declarative style, that directly maps the formalized specs to language semantics, is it even actually possible to express the specs in runnable form in a separate way, that adds value? The more obvious aspect of unit tests is to track down errors that cannot be revealed through static analysis. Given that type safe functional code is a good tool to code extremely close to what your static analyzer understands. However a simple mistake like using x instead of y (both being coordinates) in your code cannot be covered. However such a mistake could also arise while writing the test code, so I am not sure whether its worth the effort. Unit tests do introduce redundancy, which means that when requirements change, the code implementing them and the tests covering this code must both be changed. This overhead of course is about constant, so one could argue, that it doesn't really matter. In fact, in languages like Ruby it really doesn't compared to the benefits, but given how statically typed functional programming covers a lot of the ground unit tests are intended for, it feels like it's a constant overhead one can simply reduce without penalty. From this I'd deduce that unit tests are somewhat obsolete in this programming style. Of course such a claim can only lead to religious wars, so let me boil this down to a simple question: When you use such a programming style, to which extents do you use unit tests and why (what quality is it you hope to gain for your code)? Or the other way round: do you have criteria by which you can qualify a unit of statically typed functional code as covered by the static analyzer and hence needs no unit test coverage?

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  • I need a decent alternative to c++ [closed]

    - by wxiiir
    I've learned php and c++, i will list the things i liked and didn't liked on each of them, how i decided to learn them in the first place and why i feel the need to learn a decent alternative to c++, i'm not a professional programmer and only do projects for myself. PHP - Decided to learn because i wanted to build a dynamic website, that i did and turned out very good, i even coded a 'not so basic' search engine for it that would display the results 'google style' and really fast, pretty cool stuff. PROS - Pretty consistent syntax for all stuff (minor caveats), great functionality, a joy for me to code in it (it seems to 'know' what i want it to do and just does it) CONS - Painfully slow for number crunching (which takes me to c++ that i only learned because i wanted to do some number crunching and it had to be screaming fast) C++ - Learned because number crunching was so slow in php and manipulating large amounts of data was very difficult, i thought, it's popular programming language and all, and tests show that it's fast, the basic stuff resemble php so it shouldn't be hard to pick up PROS - It can be used to virtually anything, very very fast CONS - Although fun to code at the start, if i need to do something out of the ordinary, memory allocation routines, pointer stuff, stack sizes etc... will get me tired really quick, syntax is a bit inconsistent some times (more caveats) I guess that from what i wrote you guys will understand what i'm looking for, there are thousands of languages out there, it's likely that one of them will suit my needs, i've been seeing stuff today and a friend of mine that is a professional programmer tried OCaml and Fortran and said that both are fast for numerical stuff, i've been inclined to test Fortran, but i need some more input because i want to have some other good 'candidates' to choose from, for example the python syntax seemed great to me, but then i found out from some tests that it was a lot slower than c++ and i simply don't want to twiddle my thumbs all day.

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  • Decision Tree code golf

    - by Chris Jester-Young
    In Google Code Jam 2009, Round 1B, there is a problem called Decision Tree that lent itself to rather creative solutions. Post your shortest solution; I'll update the Accepted Answer to the current shortest entry on a semi-frequent basis, assuming you didn't just create a new language just to solve this problem. :-P Current rankings: 107 Perl 121 PostScript (binary) 136 Ruby 154 Arc 160 PostScript (ASCII85) 170 PostScript 192 Python 199 Common Lisp 214 LilyPond 222 JavaScript 273 Scheme 280 R 312 Haskell 314 PHP 339 m4 346 C 406 Fortran 462 Java 476 Java (well, kind of) 718 OCaml 759 F# 1741 sed C++ not qualified for now

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  • functional-style datatypes in Python

    - by Danny Roberts
    For anyone who's spent some time with sml, ocaml, haskell, etc. when you go back to using C, Python, Java, etc. you start to notice things you never knew were missing. I'm doing some stuff in Python and I realized what I really want is a functional-style datatype like (for example) datatype phoneme = Vowel of string | Consonant of voice * place * manner datatype voice = Voiced | Voiceless datatype place = Labial | Dental | Retroflex | Palatal | Velar | Glottal datatype manner = Stop | Affricate | Fricative | Nasal | Lateral type syllable = phoneme list Does anyone have a particular way that they like to simulate this in Python?

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  • In what areas might the use of F# be more appropriate than C#?

    - by Peter McGrattan
    Over the last few years F# has evolved into one of Microsoft's fully supported languages employing many ideas incubated in OCaml, ML and Haskell. Over the last several years C# has extended it's general purpose features by introducing more and more functional language features: LINQ (list comprehension), Lamdas, Closures, Anonymous Delegates and more... Given C#'s adoption of these functional features and F#'s taxonomy as an impure functional language (it allows YOU to access framework libraries or change shared state when a function is called if you want to) there is a strong similarity between the two languages although each has it's own polar opposite primary emphasis. I'm interested in any successful models employing these two languages in your production polyglot programs and also the areas within production software (web apps, client apps, server apps) you have written in F# in the past year or so that you would previously have written in C#. EDIT: Edited based on feedback from close votes with the intent of reducing perceived ambiguity.

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  • Pattern matching in Perl ala Haskell

    - by Paul Nathan
    In Haskell (F#, Ocaml, and others), I can do this: sign x | x > 0 = 1 | x == 0 = 0 | x < 0 = -1 Which calculates the sign of a given integer. This can concisely express certain logic flows; I've encountered one of these flows in Perl. Right now what I am doing is sub frobnicator { my $frob = shift; return "foo" if $frob eq "Foomaticator"; return "bar" if $frob eq "Barmaticator"; croak("Unable to frob legit value: $frob received"); } Which feels inexpressive and ugly. This code has to run on Perl 5.8.8, but of course I am interested in more modern techniques as well.

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  • Can I install WhizzyTeX for Emacs on a Mac (is Mac OS X a unix environment)?

    - by Vivi
    I think my question is pretty stupid, but here it goes: I am using Aquamacs, and I want to install the WhizzyTeX mode. The website for WhizzyTeX says that "it is designed for Unix platforms". I read that Mac OS X is unix certified, but does that mean I can install WhizzyTeX on my mac? If yes, can I install and use it with Aquamacs or do I have to use the Emacs running from the terminal? PS: I don't know whether this question should be posted here or on SuperUser, but as Emacs users seem to hang out here more often, this is the place I chose. EDIT: There are some websites saying I can use WhizzyTeX with Carbon Emacs on mac os x, but some places say I cannot (see for example this pdf document, page 27, which says that "* whizzytex: http://cristal.inria.fr/whizzytex/ mode in latex with ocaml good fo linux, should also work in cygwin, doe not work on osx"). So I am really confused...

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  • What production software have you written in F# in the past year or so that you would previously hav

    - by Peter McGrattan
    Over the last few years F# has evolved into one of Microsoft's fully supported languages employing many ideas incubated in OCaml, ML and Haskell. Over the last several years C# has extended it's general purpose features by introducing more and more functional language features: LINQ (list comprehension), Lamdas, Closures, Anonymous Delegates and more... Given C#'s adoption of these functional features and F#'s taxonomy as an impure functional language (it allows YOU to access framework libraries or change shared state when a function is called if you want to) there is a strong similarity between the two languages although each has it's own polar opposite primary emphasis. I'm interested in any successful models employing these two languages in your production polyglot programs and also the areas within production software (web apps, client apps, server apps) you have written in F# in the past year or so that you would previously have written in C#.

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  • In what specific areas has F# proven more applicable than C#?

    - by Peter McGrattan
    Over the last few years F# has evolved into one of Microsoft's fully supported languages employing many ideas incubated in OCaml, ML and Haskell. Over the last several years C# has extended it's general purpose features by introducing more and more functional language features: LINQ (list comprehension), Lamdas, Closures, Anonymous Delegates and more... Given C#'s adoption of these functional features and F#'s taxonomy as an impure functional language (it allows YOU to access framework libraries or change shared state when a function is called if you want to) there is a strong similarity between the two languages although each has it's own polar opposite primary emphasis. I'm interested in any successful models employing these two languages in your production polyglot programs and also the areas within production software (web apps, client apps, server apps) you have written in F# in the past year or so that you would previously have written in C#. EDIT: Altered title with the intent of reducing perceived ambiguity.

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  • F#: Can't hide a type abbreviation in a signature? Why not?

    - by Nels Beckman
    In F#, I'd like to have what I see as a fairly standard Abstract Datatype: // in ADT.fsi module ADT type my_Type // in ADT.fs module ADT type my_Type = int In other words, code inside the module knows that my_Type is an int, but code outside does not. However, F# seems to have a restriction where type abbreviations specifically cannot be hidden by a signature. This code gives a compiler error, and the restriction is described here. If my_Type were instead a discriminated union, then there is no compiler error. My question is, why the restriction? I seem to remember being able to do this in SML and Ocaml, and furthermore, isn't this a pretty standard thing to do when creating an abstract datatype? Thanks

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  • Will Haskell be a good choice for my task?

    - by Narzanka
    I'm starting a new project and don't know which language to use. My 'must have' requirements are: Be able to run on Windows/LinuxMacOs natively (native executable) - user should be able to just run the exe (when on Windows for example) and see the results. No runtimes/interpreters (no jvm, clr, etc) - one file download should be enough to run the application. Full unicode support. Be able to manipulate OS threads (create them, run multiple tasks in parallel on multi-core CPUs, etc). Be reasonably fast (Python level performance and better). To have some kind of standard library that does low-level, mundane tasks. Not very niche and have some community behind it to be able to ask questions. My 'nice to have' requirements are: Language should be functional It should have good string manipulation capabilities (not necessarily regex) Not extremely hard to learn I'm thinking about Haskell now but keeping in mind OCaml as well. Please advice if my choice is correct.

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  • Can parser combinators be made efficient?

    - by Jon Harrop
    Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

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  • Find min. "join" operations for sequence

    - by utyle
    Let's say, we have a list/an array of positive integers x1, x2, ... , xn. We can do a join operation on this sequence, that means that we can replace two elements that are next to each other with one element, which is sum of these elements. For example: - array/list: [1;2;3;4;5;6] we can join 2 and 3, and replace them with 5; we can join 5 and 6, and replace them with 11; we cannot join 2 and 4; we cannot join 1 and 3 etc. Main problem is to find minimum join operations for given sequence, after which this sequence will be sorted in increasing order. Note: empty and one-element sequences are sorted in increasing order. Basic examples: for [4; 6; 5; 3; 9] solution is 1 (we join 5 and 3) for [1; 3; 6; 5] solution is also 1 (we join 6 and 5) What I am looking for, is an algorithm that solve this problem. It could be in pseudocode, C, C++, PHP, OCaml or similar (I mean: I woluld understand solution, if You wrote solution in one of these languages). I would appreciate Your help.

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  • F# and statically checked union cases

    - by Johan Jonasson
    Soon me and my brother-in-arms Joel will release version 0.9 of Wing Beats. It's an internal DSL written in F#. With it you can generate XHTML. One of the sources of inspiration have been the XHTML.M module of the Ocsigen framework. I'm not used to the OCaml syntax, but I do understand XHTML.M somehow statically check if attributes and children of an element are of valid types. We have not been able to statically check the same thing in F#, and now I wonder if someone have any idea of how to do it? My first naive approach was to represent each element type in XHTML as a union case. But unfortunately you cannot statically restrict which cases are valid as parameter values, as in XHTML.M. Then I tried to use interfaces (each element type implements an interface for each valid parent) and type constraints, but I didn't manage to make it work without the use of explicit casting in a way that made the solution cumbersome to use. And it didn't feel like an elegant solution anyway. Today I've been looking at Code Contracts, but it seems to be incompatible with F# Interactive. When I hit alt + enter it freezes. Just to make my question clearer. Here is a super simple artificial example of the same problem: type Letter = | Vowel of string | Consonant of string let writeVowel = function | Vowel str -> sprintf "%s is a vowel" str I want writeVowel to only accept Vowels statically, and not as above, check it at runtime. How can we accomplish this? Does anyone have any idea? There must be a clever way of doing it. If not with union cases, maybe with interfaces? I've struggled with this, but am trapped in the box and can't think outside of it.

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  • Want to add a functional language to my toolchest. Haskell or Erlang?

    - by sean.johnson
    I've been an OO/procedural guy my whole career except in school where I did a lot of logic programming (Prolog). I work on an amazing variety of projects (freelancer) and so I don't want the tools I know and understand to hold me back from using the right tool for the job. I've decided I should know a functional programming language. I've narrowed the field to Haskell and Erlang. What are the pros and cons, advantages and disadvantages, and major trade offs of Haskell and Erlang? How do I decide in a rational way, which is the better path? This is a big time investment, so I'd like to chose wisely. Is there a good case to be made for something else entirely? F#, Scala Ocaml? (BTW, I'm normally a Ruby/C/Obj.C guy, so I'm not terribly impressed or dependent on the JVM as a runtime. It's completely neutral to me. It's a fine runtime, I don't hold it for or against a language. I don't use Microsoft products though, so a .NET runtime would be a negative.)

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  • Can parser combination be made efficient?

    - by Jon Harrop
    Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and shift oop f op (P(g, xs)) = let h, xs = loop (op, g, xs) loop (oop, f h, xs) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) | oop, f, ('^' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) | '^' -> pown loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '-'::P(f, xs) -> let f, xs = loop ('~', f, xs) P(-f, xs) | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

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  • The best cross platform (portable) arbitrary precision math library

    - by Siu Ching Pong - Asuka Kenji
    Dear ninjas / hackers / wizards, I'm looking for a good arbitrary precision math library in C or C++. Could you please give me some advices / suggestions? The primary requirements: It MUST handle arbitrarily big integers (my primary interest is on integers). In case that you don't know what the word arbitrarily big means, imagine something like 100000! (the factorial of 100000). The precision MUST NOT NEED to be specified during library initialization / object creation. The precision should ONLY be constrained by the available resources of the system. It SHOULD utilize the full power of the platform, and should handle "small" numbers natively. That means on a 64-bit platform, calculating 2^33 + 2^32 should use the available 64-bit CPU instructions. The library SHOULD NOT calculate this in the same way as it does with 2^66 + 2^65 on the same platform. It MUST handle addition (+), subtraction (-), multiplication (*), integer division (/), remainder (%), power (**), increment (++), decrement (--), gcd(), factorial(), and other common integer arithmetic calculations efficiently. Ability to handle functions like sqrt() (square root), log() (logarithm) that do not produce integer results is a plus. Ability to handle symbolic computations is even better. Here are what I found so far: Java's BigInteger and BigDecimal class: I have been using these so far. I have read the source code, but I don't understand the math underneath. It may be based on theories / algorithms that I have never learnt. The built-in integer type or in core libraries of bc / Python / Ruby / Haskell / Lisp / Erlang / OCaml / PHP / some other languages: I have ever used some of these, but I have no idea on which library they are using, or which kind of implementation they are using. What I have already known: Using a char as a decimal digit, and a char* as a decimal string and do calculations on the digits using a for-loop. Using an int (or a long int, or a long long) as a basic "unit" and an array of it as an arbitrary long integer, and do calculations on the elements using a for-loop. Booth's multiplication algorithm What I don't know: Printing the binary array mentioned above in decimal without using naive methods. Example of a naive method: (1) add the bits from the lowest to the highest: 1, 2, 4, 8, 16, 32, ... (2) use a char* string mentioned above to store the intermediate decimal results). What I appreciate: Good comparisons on GMP, MPFR, decNumber (or other libraries that are good in your opinion). Good suggestions on books / articles that I should read. For example, an illustration with figures on how a un-naive arbitrarily long binary to decimal conversion algorithm works is good. Any help. Please DO NOT answer this question if: you think using a double (or a long double, or a long long double) can solve this problem easily. If you do think so, it means that you don't understand the issue under discussion. you have no experience on arbitrary precision mathematics. Thank you in advance! Asuka Kenji

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