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  • How to access class member from bison action

    - by yodhevauhe
    I am calling yyparse from a member function. How to access the member variables/function from the bison action. I am currently doing as %{ #include "myclass.h" #include "parse.tab.hh" MyClass *ptr=NULL; void MyClass::evaluate(string expression) { ptr=this; yy_scan_string(expression.c_str()); yyparse(); } %} %% EXPR : EXPR PLUS EXPR { $$ = ptr->memberFunction("+",$1,$3); }

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  • Specializing a template on a lambda in C++0x

    - by Tony A.
    I've written a traits class that lets me extract information about the arguments and type of a function or function object in C++0x (tested with gcc 4.5.0). The general case handles function objects: template <typename F> struct function_traits { template <typename R, typename... A> struct _internal { }; template <typename R, typename... A> struct _internal<R (F::*)(A...)> { // ... }; typedef typename _internal<decltype(&F::operator())>::<<nested types go here>>; }; Then I have a specialization for plain functions at global scope: template <typename R, typename... A> struct function_traits<R (*)(A...)> { // ... }; This works fine, I can pass a function into the template or a function object and it works properly: template <typename F> void foo(F f) { typename function_traits<F>::whatever ...; } int f(int x) { ... } foo(f); What if, instead of passing a function or function object into foo, I want to pass a lambda expression? foo([](int x) { ... }); The problem here is that neither specialization of function_traits<> applies. The C++0x draft says that the type of the expression is a "unique, unnamed, non-union class type". Demangling the result of calling typeid(...).name() on the expression gives me what appears to be gcc's internal naming convention for the lambda, main::{lambda(int)#1}, not something that syntactically represents a C++ typename. In short, is there anything I can put into the template here: template <typename R, typename... A> struct function_traits<????> { ... } that will allow this traits class to accept a lambda expression?

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  • Is there a more modern regexp handler for Open Object Rexx

    - by Brent.Longborough
    The regular expression class (rxregexp.dll) that comes with ooRexx (I'm on 4.0.0) is relatively low on function compared, say, with Python's re module (even at 2.5.2). It appears to have no assertions, no facilities for group extraction, or for substitution. Greedy or lazy matching is a global pattern option, rather than flagged by an additional "?". Basically, a pre-PCRE regular expression engine. Does anyone know if anything with more up-to-date function is available?

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  • child objects in rdlc (Studio 2010RC)

    - by Jim
    Hi, I am attempting to reference a sub-object in a field expression in a studio 2010 report. This used to work in prior versions. When account references another object with properties the following used to work. =Fields!Account.Value.Name (Name is a property of the child object, Account is the parent object) The same expression syntax no longer works. How do I reference the properties of a sub-object in reporting services in an rdlc in studio 2010. Thanks

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  • In Java, is it possible for a super constructor invocation actually invoke a constructor in the calling class?

    - by John Assymptoth
    Super constructor invocation definition: [Primary.] [NonWildTypeArguments] super ( ArgumentListopt ) ; A super constructor call can be prefixed by an Primary expression. Example (taken from JLS): class Outer { class Inner{ } } class ChildOfInner extends Outer.Inner { ChildOfInner() { (new Outer()).super(); // (new Outer()) is the Primary } } Does a Primary expression exist that makes the call to super() the invocation of a constructor of the calling class? Or Java prevents that?

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  • Why doesn't Java warn about a == "something"?

    - by Marius
    This might sound stupid, but why doesn't the Java compiler warn about the expression in the following if statement: String a = "something"; if(a == "something"){ System.out.println("a is equal to something"); }else{ System.out.println("a is not equal to something"); } I realize why the expression is untrue, but AFAIK, a can never be equal to the String literal "something". The compiler should realize this and at least warn me that I'm an idiot who is coding way to late at night.

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  • uncaught exception: Syntax error after jQuery upgrade

    - by wham12
    I am trying to upgrade an existing application from jQuery 1.3.2 to jQuery 1.4.2. When I do this, the page fails to load correctly and firefox's error console displays the error message "uncaught exception: Syntax error, unrecognized expression: Syntax error, unrecognized expression: search". How can I determine what is causing this exception?

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  • Regex for Password Must be contain at least 8 characters, least 1 number and both lower and uppercase letters and special characters

    - by user2442653
    I want a regular expression to check that Password Must be contain at least 8 characters, including at least 1 number and includes both lower and uppercase letters and special characters (e.g., #, ?, !) Cannot be your old password or contain your username, "password", or "websitename" And here is my validation expression which is for 8 characters including 1 uppercase letter, 1 lowercase letter, 1 number or special character. (?=^.{8,}$)((?=.*\d)|(?=.*\W+))(?![.\n])(?=.*[A-Z])(?=.*[a-z]).*$" How I can write it for password must be 8 characters including 1 uppercase letter, 1 special character and alphanumeric characters?

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  • HtmlHelperExtensions are not visible in view mvc3 asp.net

    - by user1299372
    I've added a class for the HTML Custom Extensions: using System; using System.Linq.Expressions; using System.Text; using System.Web.Mvc; using System.Web.Mvc.Html; namespace App.MvcHtmlHelpers { public static class HtmlHelperExtensions { public static MvcHtmlString ComboBox(HtmlHelper html, string name, SelectList items, string selectedValue) { var sb = new StringBuilder(); sb.Append(html.DropDownList(name + "_hidden", items, new { @style = "width: 200px;", @onchange = "$('input#" + name + "').val($(this).val());" })); sb.Append(html.TextBox(name, selectedValue, new { @style = "margin-left: -199px; width: 179px; height: 1.2em; border: 0;" })); return MvcHtmlString.Create(sb.ToString()); } public static MvcHtmlString ComboBoxFor<TModel, TProperty>(HtmlHelper<TModel> html, Expression<Func<TModel, TProperty>> expression, SelectList items) { var me = (MemberExpression)expression.Body; var name = me.Member.Name; var sb = new StringBuilder(); sb.Append(html.DropDownList(name + "_hidden", items, new { @style = "width: 200px;", @onchange = "$('input#" + name + "').val($(this).val());" })); sb.Append(html.TextBoxFor(expression, new { @style = "margin-left: -199px; width: 179px; height: 1.2em; border: 0;" })); return MvcHtmlString.Create(sb.ToString()); } I've also registered it in my site web config: <namespaces> <add namespace="System.Web.Helpers" /> <add namespace="System.Web.Mvc" /> <add namespace="System.Web.Mvc.Ajax" /> <add namespace="System.Web.Mvc.Html" /> <add namespace="System.Web.Routing" /> <add namespace="System.Web.WebPages" /> <add namespace="App.MvcHtmlHelpers"/> </namespaces> In my view, I import the namespace: <%@ Import Namespace="RSPWebApp.MvcHtmlHelpers" %> But when I go to call it in the view, it doesn't recognize the custom extension. Can someone help me by telling me what I might have missed? Thanks so much in advance! <%:Html.ComboBoxFor(a => a.Street2, streetAddressListItems) %

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  • How to create dynamic number of output files with SSIS?

    - by JSacksteder
    I will be creating flatfiles and based on the data in the batch, it might be necessary to split the data into an undetermined number of files. I can make the connection string dynamic with an expression, but that is only evaluated when the package starts. I'd like to change that expression to include a '-a' or '-b' in the filename. Alternately, if I have to create new connection manager objects at run time on demand, how do I go about that?

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  • help with regex needed

    - by user268375
    I need a regular expression with the following needs: the string is alphanumeric and have exactly 6 characters in the first half followed by hyphen(optional) followed by optional 4 characters:(cannot have more than 4 characters in the second half) so any of the following is valid 11111A 111111-1 111111-yy yyyyy-989 yyyyyy-9090 i thought this expression /[a-zA-Z0-9]([-])?[a-zA-Z0-9]{5,10}$/; should work but i m unable to get it working correctly. Any help will be appreciated,

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  • DataColumn expressions

    - by Kumar
    What is the most complex expression you've seen/used ? and what's the limit on the length of the expression that can be used ? I seem to recall something to that effect a while back but can't locate it now !!

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  • How can you remove a Criterion from a criteria?

    - by ChuckM
    Hello, For instance if I do something like: Criteria c = session.createCriteria(Book.class) .add(Expression.ge("release",reDate); .add(Expression.ge("price",price); .addOrder( Order.asc("date") ) .setFirstResult(0) .setMaxResults(10); c.list(); How can I use the same criteria instance, but remove (for example) the second criterion? I'm trying to build a dynamic query in which I'd like to let the user remove a filter, without the backend having to reconstruct the criteria from scratch. Thank you

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  • Does this e-mail-regex exclude valid addresses?

    - by neo
    I tried to create a regular expression which catches all RFC-valid addresses but it's ok if some false-positives come through (though hopefully not so many). This is waht I came up so far: /^\b\S+@\S+\.[^\s@]{2,}\b$/ Is there any RFC-valid address which doesn't match against this expression or do you have any suggestions to improve it? I don't mind the false positives but I would be glad if you show me a few, too.

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  • Javascript regular expressions: how to match ONLY the given characters?

    - by Dfowj
    I'm trying to use a regex like /[computer]{3,8}/ to get any words containing only the letters in computer ranging from 3 to 8 letters long. That regex instead captures all words containing ANY of the letters in [computer]. I've been looking at regular expression examples, but i can't quite figure it out... How do i modifiy this regular expression to capture words containing ONLY the letters in computer (with a length of 3 to 8)?

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  • Haskell "Source reduction"

    - by Martin
    I'm revising for an upcoming Haskell exam and I don't understand one of the questions on a past paper. Google turns up nothing useful fst(x, y) = x square i = i * i i) Source reduce, using Haskells lazy evaluation, the expression: fst(square(3+4), square 8) ii) Source reduce, using strict evaluation, the same expression iii) State one advantage of lazy evaluation and one advantage of strict evaluation

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  • Copying an entire table with Postgres

    - by NudeCanalTroll
    Hello, I'm trying to copy the contents of one table into another in Postgres, however it appears some rows aren't being copied correctly: ActiveRecord::StatementInvalid: PGError: ERROR: column "email_date" is of type timestamp without time zone but expression is of type character varying HINT: You will need to rewrite or cast the expression. Is there any way I can have it automatically skip (or ignore) invalid rows? Here's the query I'm using: SET statement_timeout = 0; INSERT INTO emails3 SELECT * FROM emails

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  • Handling a colon in an element ID in a CSS selector

    - by sblundy
    JSF is setting the ID of an input field to search_form:expression. I need to specify some styling on that element, but that colon looks like the beginning of a pseudo-element to the browser so it gets marked invalid and ignored. Is there anyway to escape the colon or something? input#search_form:expression { ///... }

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  • Passing template into boost function

    - by Ockonal
    template <class EventType> class IEvent; class IEventable; typedef boost::function<void (IEventable&, IEvent&)> behaviorRef; What is the right way for passing template class IEvent into boost function? With this code I get: error: functional cast expression list treated as compound expression error: template argument 1 is invalid error: invalid type in declaration before ‘;’ token

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  • Doubt in Conditional inclusion

    - by Philando Gullible
    This is actually extracted from my module (Pre-processor in C) The conditional expression could contain any C operator except for the assignment operators,increment, and decrement operators. I am not sure if I am getting this statement or not since I tried using this and it worked.Also for other manipulation a probable work around would be to simply declare macro or function inside the conditional expression,something like this to be precise. Also I don't understand what is the rationale behind this rule. Could somebody explain? Thanks

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  • GPGPU

    WhatGPU obviously stands for Graphics Processing Unit (the silicon powering the display you are using to read this blog post). The extra GP in front of that stands for General Purpose computing.So, altogether GPGPU refers to computing we can perform on GPU for purposes beyond just drawing on the screen. In effect, we can use a GPGPU a bit like we already use a CPU: to perform some calculation (that doesn’t have to have any visual element to it). The attraction is that a GPGPU can be orders of magnitude faster than a CPU.WhyWhen I was at the SuperComputing conference in Portland last November, GPGPUs were all the rage. A quick online search reveals many articles introducing the GPGPU topic. I'll just share 3 here: pcper (ignoring all pages except the first, it is a good consumer perspective), gizmodo (nice take using mostly layman terms) and vizworld (answering the question on "what's the big deal").The GPGPU programming paradigm (from a high level) is simple: in your CPU program you define functions (aka kernels) that take some input, can perform the costly operation and return the output. The kernels are the things that execute on the GPGPU leveraging its power (and hence execute faster than what they could on the CPU) while the host CPU program waits for the results or asynchronously performs other tasks.However, GPGPUs have different characteristics to CPUs which means they are suitable only for certain classes of problem (i.e. data parallel algorithms) and not for others (e.g. algorithms with branching or recursion or other complex flow control). You also pay a high cost for transferring the input data from the CPU to the GPU (and vice versa the results back to the CPU), so the computation itself has to be long enough to justify the overhead transfer costs. If your problem space fits the criteria then you probably want to check out this technology.HowSo where can you get a graphics card to start playing with all this? At the time of writing, the two main vendors ATI (owned by AMD) and NVIDIA are the obvious players in this industry. You can read about GPGPU on this AMD page and also on this NVIDIA page. NVIDIA's website also has a free chapter on the topic from the "GPU Gems" book: A Toolkit for Computation on GPUs.If you followed the links above, then you've already come across some of the choices of programming models that are available today. Essentially, AMD is offering their ATI Stream technology accessible via a language they call Brook+; NVIDIA offers their CUDA platform which is accessible from CUDA C. Choosing either of those locks you into the GPU vendor and hence your code cannot run on systems with cards from the other vendor (e.g. imagine if your CPU code would run on Intel chips but not AMD chips). Having said that, both vendors plan to support a new emerging standard called OpenCL, which theoretically means your kernels can execute on any GPU that supports it. To learn more about all of these there is a website: gpgpu.org. The caveat about that site is that (currently) it completely ignores the Microsoft approach, which I touch on next.On Windows, there is already a cross-GPU-vendor way of programming GPUs and that is the DirectX API. Specifically, on Windows Vista and Windows 7, the DirectX 11 API offers a dedicated subset of the API for GPGPU programming: DirectCompute. You use this API on the CPU side, to set up and execute the kernels that run on the GPU. The kernels are written in a language called HLSL (High Level Shader Language). You can use DirectCompute with HLSL to write a "compute shader", which is the term DirectX uses for what I've been referring to in this post as a "kernel". For a comprehensive collection of links about this (including tutorials, videos and samples) please see my blog post: DirectCompute.Note that there are many efforts to build even higher level languages on top of DirectX that aim to expose GPGPU programming to a wider audience by making it as easy as today's mainstream programming models. I'll mention here just two of those efforts: Accelerator from MSR and Brahma by Ananth. Comments about this post welcome at the original blog.

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  • Windows Azure Use Case: Web Applications

    - by BuckWoody
    This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx  Description: Many applications have a requirement to be located outside of the organization’s internal infrastructure control. For instance, the company website for a brick-and-mortar retail company may want to post not only static but interactive content to be available to their external customers, and not want the customers to have access inside the organization’s firewall. There are also cases of pure web applications used for a great many of the internal functions of the business. This allows for remote workers, shared customer/employee workloads and data and other advantages. Some firms choose to host these web servers internally, others choose to contract out the infrastructure to an “ASP” (Application Service Provider) or an Infrastructure as a Service (IaaS) company. In any case, the design of these applications often resembles the following: In this design, a server (or perhaps more than one) hosts the presentation function (http or https) access to the application, and this same system may hold the computational aspects of the program. Authorization and Access is controlled programmatically, or is more open if this is a customer-facing application. Storage is either placed on the same or other servers, hosted within an RDBMS or NoSQL database, or a combination of the options, all coded into the application. High-Availability within this scenario is often the responsibility of the architects of the application, and by purchasing more hosting resources which must be built, licensed and configured, and manually added as demand requires, although some IaaS providers have a partially automatic method to add nodes for scale-out, if the architecture of the application supports it. Disaster Recovery is the responsibility of the system architect as well. Implementation: In a Windows Azure Platform as a Service (PaaS) environment, many of these architectural considerations are designed into the system. The Azure “Fabric” (not to be confused with the Azure implementation of Application Fabric - more on that in a moment) is designed to provide scalability. Compute resources can be added and removed programmatically based on any number of factors. Balancers at the request-level of the Fabric automatically route http and https requests. The fabric also provides High-Availability for storage and other components. Disaster recovery is a shared responsibility between the facilities (which have the ability to restore in case of catastrophic failure) and your code, which should build in recovery. In a Windows Azure-based web application, you have the ability to separate out the various functions and components. Presentation can be coded for multiple platforms like smart phones, tablets and PC’s, while the computation can be a single entity shared between them. This makes the applications more resilient and more object-oriented, and lends itself to a SOA or Distributed Computing architecture. It is true that you could code up a similar set of functionality in a traditional web-farm, but the difference here is that the components are built into the very design of the architecture. The API’s and DLL’s you call in a Windows Azure code base contains components as first-class citizens. For instance, if you need storage, it is simply called within the application as an object.  Computation has multiple options and the ability to scale linearly. You also gain another component that you would either have to write or bolt-in to a typical web-farm: the Application Fabric. This Windows Azure component provides communication between applications or even to on-premise systems. It provides authorization in either person-based or claims-based perspectives. SQL Azure provides relational storage as another option, and can also be used or accessed from on-premise systems. It should be noted that you can use all or some of these components individually. Resources: Design Strategies for Scalable Active Server Applications - http://msdn.microsoft.com/en-us/library/ms972349.aspx  Physical Tiers and Deployment  - http://msdn.microsoft.com/en-us/library/ee658120.aspx

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  • concurrency::accelerator_view

    - by Daniel Moth
    Overview We saw previously that accelerator represents a target for our C++ AMP computation or memory allocation and that there is a notion of a default accelerator. We ended that post by introducing how one can obtain accelerator_view objects from an accelerator object through the accelerator class's default_view property and the create_view method. The accelerator_view objects can be thought of as handles to an accelerator. You can also construct an accelerator_view given another accelerator_view (through the copy constructor or the assignment operator overload). Speaking of operator overloading, you can also compare (for equality and inequality) two accelerator_view objects between them to determine if they refer to the same underlying accelerator. We'll see later that when we use concurrency::array objects, the allocation of data takes place on an accelerator at array construction time, so there is a constructor overload that accepts an accelerator_view object. We'll also see later that a new concurrency::parallel_for_each function overload can take an accelerator_view object, so it knows on what target to execute the computation (represented by a lambda that the parallel_for_each also accepts). Beyond normal usage, accelerator_view is a quality of service concept that offers isolation to multiple "consumers" of an accelerator. If in your code you are accessing the accelerator from multiple threads (or, in general, from different parts of your app), then you'll want to create separate accelerator_view objects for each thread. flush, wait, and queuing_mode When you create an accelerator_view via the create_view method of the accelerator, you pass in an option of immediate or deferred, which are the two members of the queuing_mode enum. At any point you can access this value from the queuing_mode property of the accelerator_view. When the queuing_mode value is immediate (which is the default), any commands sent to the device such as kernel invocations and data transfers (e.g. parallel_for_each and copy, as we'll see in future posts), will get submitted as soon as the runtime sees fit (that is the definition of immediate). When the value of queuing_mode is deferred, the commands will be batched up. To send all buffered commands to the device for execution, there is a non-blocking flush method that you can call. If you wish to block until all the commands have been sent, there is a wait method you can call. Deferring is a more advanced scenario aimed at performance gains when you are submitting many device commands and you want to avoid the tiny overhead of flushing/submitting each command separately. Querying information Just like accelerator, accelerator_view exposes the is_debug and version properties. In fact, you can always access the accelerator object from the accelerator property on the accelerator_view class to access the accelerator interface we looked at previously. Interop with D3D (aka DX) In a later post I'll show an example of an app that uses C++ AMP to compute data that is used in pixel shaders. In those scenarios, you can benefit by integrating C++ AMP into your graphics pipeline and one of the building blocks for that is being able to use the same device context from both the compute kernel and the other shaders. You can do that by going from accelerator_view to device context (and vice versa), through part of our interop API in amp.h: *get_device, create_accelerator_view. More on those in a later post. Comments about this post by Daniel Moth welcome at the original blog.

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