Mads Torgersen shares future thinking of a fast-moving major programming language, C#. Torgersen discusses pattern matching, type classes, discriminated unions and much more.
Last time we saw that spinlock implementations which only use a single synchronization variable (Test-And-Set Lock, Ticket Lock) don’t scale with growing numbers of threads. Today, I want to talk about two spinlock variants that scale. Namely the Graunke and Thakkar Lock1 (1989) and the Anderson Lock2 (1990). Their underlying key idea is to use one synchronization variable per thread instead of one for all threads, to reduce the amount of cache line invalidations when acquiring/releasing the lock. Both spinlock variants store the synchronization variables in an array. This means that there’s an upper bound on the maximum number of thread’s that can compete for the lock concurrently, which must be known a priori. In upcoming blog posts I’m going to show spinlock variants (the MCS Lock and the CLH Lock) that improve upon array-based spinlocks by removing this hard upper limit.
LINQ is certainly extraordinarily useful. It brings the power of query expressions to C#, allowing an easy way of getting the data you need from a variety of data sources. Up to now, there hasn’t been a VS debugger for LINQ that gives you the means to visualise the data at every point in the chain. Michael Sorens, a keen LINQ user, describes a third-party tool that now promises to make using LINQ something we can all participate in.…
Since I’m in a C mood today: Free book: [WayBack] Writing Bug-Free C Code, A Programming Style That Automatically Detects Bugs in C Codeby Jerry Jongerius / January 1995.
Ah, C. The best lingua franca we have… because we have no other lingua francas. Linguae franca. Surgeons general? C is fairly old — 44 years, now! — and comes from a time when there were possibly more architectures than programming languages. It works well for what it is, and what it is is a relatively simple layer of indirection atop assembly. Alas, the popularity of C has led to a number of programming languages’ taking significant cues from its design, and parts of its design are… slightly questionable. I’ve gone through some common features that probably should’ve stayed in C and my justification for saying so. The features are listed in rough order from (I hope) least to most controversial. The idea is that C fans will give up when I call it “weakly typed” and not even get to the part where I rag on braces. Wait, crap, I gave it away.
Oh nice. Feel free to QP. Fails at least in Delphi XE8.
program E2003WithConstsInDescendingClassesConsoleProject;
{$APPTYPE CONSOLE}
uses
ParentUnit in 'ParentUnit.pas',
ChildUnit in 'ChildUnit.pas';
begin
end.
unit ParentUnit;
interface
type
TParent = class
// section can be strict protected, protected, public, published or nothing
const
InitialBooleanValue = False;
InitialIntegerValue = -1;
end;
implementation
end.
unit ChildUnit;
interface
uses
ParentUnit;
type
TChild = class(TParent)
// section can be strict protected, protected, public, published or nothing
const
// Initial and final values need to be different to test the behaviour
FinalBooleanValue = not InitialBooleanValue;
FinalIntegerValue = InitialIntegerValue + 1;
//[dcc32 Error] ChildUnit.pas(13): E2003 Undeclared identifier: 'InitialBooleanValue'
//[dcc32 Error] ChildUnit.pas(14): E2003 Undeclared identifier: 'InitialIntegerValue'
//[dcc32 Error] ChildUnit.pas(14): E2026 Constant expression expected
end;
implementation
end.
First example is to eliminate outliers in the below graph.
He also has a really cool (German) Playlist on data analysis with Python called Datenanalyse in Python and has a great site with examples at franz.media.
The Wiert Corner - irregular stream of stuff 