Contents

Blog tags RSS

Structure and Interpretation of Computer Programs

16 April 2008 (books programming ISC) (11 comments)

Az egyik dolog, amit nagyon szeretek a progmaton a Simon-féle analízis kurzusban, az az, ahogyan gyakorlatilag a semmiből, vagyis a ZF-ből és a valós számok axiómáiból építkezünk, és ha néha ki is hagyunk egy-egy bizonyítást, akkor arra külön fel van hívva a figyelmünk. Ennek az a csodálatos eredménye, hogy még így a hatodik félév közepén is bármilyen bonyolult tétel bizonyítása esetén elvileg rekonstruálható a teljes út az axiómáktól.

Structure and Interpretation of Computer Programs

A SICP, mint alant kifejtem, ugyanilyen előadássorozat illetve könyv, a programozásról. Én egy-két évvel ezelőtt először az előadással találkoztam, ma már nem tudom, miért hagytam abba akkoriban a 6. előadás környékén. Most viszont elémkerült a könyv is, nekiugrottam, és kiderült, hogy a lényeg pont a második felében van.

Hal Abelson Az első három fejezet ugyanis bármelyik, hasonló témájú könyvben előfordulna: az absztrakció különböző, egymásra épülő vagy éppen ortogonális szintjei, mint pl. (magasabbrendű) függvények, adatok és műveleteik együttes kezelése (hadd ne mondjam típus), az imperatív megközelítés a maga értékadásos-mellékhatásos fekélyeivel, Haskell-szerű lazy evaluáció. Az összes illusztráció Scheme-ben, egy Lisp dialektusban íródott, valójában az első három fejezet éppen arról szól, ahogyan a fenti absztrakciós eszközök céljainak megvizsgálásával felépül a nyelv szemantikája.

Az érdekességek a negyedik fejezetben kezdődnek. Először, egyfajta baseline-ként bemutat egy Scheme-ben írt Scheme interpretert, ennek ugye Lispben eleve komoly hagyományai vannak (összehasonlíthatatlanul olvashatóbb a mai szemnek ugyanennek a cikknek a Paul Graham által felújított változata). Ezzel már sokkal valóságosabbá válnak az eddigi programok, hiszen bár a kígyó még a saját farkába harap, de már kezünkben van az axiómáknak az a véges halmaza, amikből a konkrét Scheme programok szemantikája levezethető.

Gerald Jay Sussman Ezekután bemutatja a Scheme pár leágazását, és persze hogy itt válik érdekeltté az intencionális programozó. A Lispben ugye régóta kultúrája van annak, hogy a problémákat a hozzájuk illesztett nyelven oldjuk meg, és utána vagy írjuk meg ennek a nyelvnek az értelmezését, vagy ágyazzuk be a nyelvet a Lispbe. Így aztán a tipikus Lisp programozó a legritkább esetben programozik Lispben, sokkal gyakrabban mindenféle ad-hoc Lisp' meg Lisp'' nyelvekben. A negyedik fejezet ilyen Scheme' nyelveket mutat be a lazy evaluációhoz és a nemdeterminisztikus futási szemantikához (ez utóbbi egyébként valószínűleg közel áll ahhoz, ahogyan a kvantumszámítógépeket fogjuk magasszinten programozni); illetve egy interpretált constraint-nyelvet.

És végül az utolsó fejezet az, ami odavág. Nem azért, mintha nem láttunk volna még a bootstrap-probléma megoldására gépi kódban írt compilert, hanem azért, ahogyan kerekké teszi a könyvet. Itt jön be ugyanis a korábban említett párhuzam az anal-kurzussal. Bebizonyítjuk, hogy létezik rendezett teljestest: a valódi, fizikai számítógépeket leíró regisztergép-modellen az utolsó bitig egyértelművé válik minden maradék kérdésre a válasz, a bemutatott, gépi kódú Scheme interpreter és fordító pedig hirtelen megfoghatóvá tesz minden, a könvyben megelőző példát. Handwaving-nek nyoma sem marad. Ahogy az utolsó előtti előadáson Abelson mondja: az utolsó, legnagyobb varázslat, hogy kiírtjuk a rendszerből a mágiát.


« Munkamorál 
All entries
 Titanic: Szamócás süti »


ivbubquo (http://www.newlookbras.com) 2012-03-26 09:32:54

Ahogy az utolsó előtti előadáson Abelson mondja: az utolsó, legnagyobb varázslat, hogy kiírtjuk a rendszerből a mágiát. energy saving light

fefe (http://www.myobdscanner.com/) 2012-09-19 11:16:44

Jill writes regarding the necessary methods for sustaining launch creader vi a wholesome and exquisite . For extra support, tips or enthusiasm check out her web site on elm327 usb!

chanel tote bags 2012-11-01 09:50:11

adies, when you need the most effective with the tote planet, right now there practically nothing a lot more best over a Chanel tote. In case you are really thinking of buying Chanel tote, an individual earned feel simply how much assortment there is certainly on the web? youl become drooling on the wide variety of types and also shades regarding Chanel totes. School, cheap louis vuitton handbags type and also ease and comfort are usually a few terms in which identify the particular Chanel line of fashion accessories. Coco Chanel has been any pioneer inside females garments and also components. Once you sports activity any stylish Chanel tote on your own provide, an individual elizabeth having over a extended traditions regarding females which really like vintage type in which exciting and also secure. One of many special things about the particular Chanel carrier will be the quilted buckskin layout. Although chanel tote bags youl realize that Chanel tends to make numerous methods of totes, they will nonetheless provide vintage quilted Chanel carrier. These kinds of hand bags are usually legends inside the trend planet. Typically, an individual louis vuitton leather bags have got to attend any Chanel flagship retailer, or perhaps high-end section retailer to get Chanel artist totes and also bags, and you also pay out a fairly any amount of money per a single Thankfully, the world wide web gives a lot of options for your trend knowledgeable girl to get top-of-the-line artist totes with good deal rates.

training course, we all elizabeth discussing Chanel the following, cheap bags online and that means you elizabeth nonetheless planning to pay out a wholesome value, but instead of just one carrier, youl manage to acquire several. Girls, you understand right now there nothing can beat the particular type, top quality and also ease and comfort of your traditional Chanel tote. It doesn't matter what the disposition, right now there any Chanel tote to fit. That a brilliant thought to look on the web to get Chanel tote, given that youl manage to locate several great discounts. Don acquire also carried away, even though. Youl need to be sure an individual elizabeth acquiring simply traditional Chanel armani watches rather than in which low-cost counterfeit products. Prior to deciding to acquire, I suggest exploring a lot of hand bags to get familiar with just what a genuine Chanel carrier seems like. Don obtain virtually any owner that gives that you' unny experience. What kinds of Chanel totes is it possible to acquire on the web? The particular heavens the particular reduce. Buckskin, fur, wicker, art print, fresh, antique, african american, white-colored, bronze, reddish, environmentally friendly, glowing blue, white, clutch i465 black, cheap armani watches drawstring, tote, bag, messenger carrier, specific editions, and so forth. You definitely earned increase bored with your choices regarding types and also shades. There simply no will need so that you can stay near any Chanel store or perhaps high-end section retailer in which holds these kinds of exceptional hand bags. Your brand-new Chanel carrier will be delightfully close at hand.

campaign (http://www.coachoutletstoreps.com) 2012-11-21 04:55:44

The Breezy Coach Outlet Store OnlinePoint neighborhood at the tip of the Rockaway Peninsula in Coach Outlet OnlineQueens, N.Y., where more than 100 homes were consumed by fires during Superstorm Sandy.Coach OutletHurricane Sandy Damage Amplified By Breakneck Development Of Gucci BeltCoast The Huffington PostAs Coasts Rebuild and U.S. Pays, Repeatedly, theCoach Factory Outlet Critics Ask Why The New York TimesIt’s so obvious we forget it: Coach Factory Outletan extreme weather event becomes a disaster only if it hits where people and their Gucci Beltspossessions are. Of the 19 tropical storms that were tracked during this Coach Factory Outletsummer’s Atlantic hurricane season, 10 veered off harmlessly into the Atlantic Coach Factory OutletOcean, never making landfall. But when a storm like Sandy tracks over the most Coach Outlet Onlineheavily populated stretch of land in the Western Hemisphere, Coach Online Outletthe damage to people and property can be immense. Sandy wasn’t the strongest Coach Factory Onlinestorm—it was just barely a Category 1 hurricane when it made Coach Outlet Onlinelandfall at the end of last month—but both its death toll and its economic Coach Factory Onlinedamage were high simply because so many people were in Hermes Beltsits path. Storm + people equals natural disaster. The hurricane is the spark, but population is Coach Factory Onlinethe tinder.

Coach Factory Online (http://www.coachfactoryoutletpst.com) 2012-11-22 03:07:05

For some,Coach Outlet Store the phrase “Dust Bowl” conjures a place: the Great Plains, butCoach Outlet Online a Great Plains of abandoned homes, ruined lives, dead and dying crops andCoach Factory Online sand, sand, sand.For others, the phrase denotes not a region but an era: Coach Factory Storethe mid- to late-1930s in America, when countless farms were lost; dust storms raced across thousands of miles of once-fertileCoach Factory Onlineland, so huge and unremitting that theyCoach Factory Storeoften blotted out the sun; and millions of American men, women and Coach Outletchildren took to the road, leaving behind everythingng they knewand everything they’d built, heading west, seeking work, Coach Outlet Onlinefood, shelter, new lives, new hope.These families, immortalized in John Steinbeck’s magisterial The Grapes of Wrath Coach Factory Outletand in the unflinching photographs of Dorothea Lange, Walker Evans and others, were almost universally known as Coach Factory Online“Okies,” whether or not they actually hailed from the devastated state of Oklahoma. The great, ragged migration Coach Online Outletaway from half-buried farms and toward California and other vague “promised lands” is one of the defining catastrophes of the Great Depression.

ch131232 2012-12-20 10:01:34

I'm remember not to going for more information regarding don't rush my very own time all around the newspaper ads and classifieds,Gucci Fanny Pack. Please understand,Gucci Sunglasses, I'm do not here to condemn any sexual that should focus all over the print reports and say that the people doing that 're doing it wrong. This is this : how do we I've gone to live in for more information on market my characteristics from Gucci Outlet.

Gucci Collection? Where the extravagant promotional cars and trucks slightly like going to be the not too long ago advertisements, newspapers ad,aimed at your website or otherwise radio promotion all it takes is extravagant cost,the flyers can be created within a multi function a few budget They can be the case equally effective as well as a multi function small scale organization and an all in one multinational company Gucci Outlet Online.

coach purses outlet (http://www.usitccoachpurses.com/) 2013-04-16 04:31:45

<p>I thought I'd never say). You will get to see when the full length version is released at the Coach outlet online Festival next week. I'll keep you guys posted!The <strong>coach purses outlet</strong> stylist's collection features formal <strong>coach outlet store</strong> and separates that look expensive, but won't break your <strong>chan luu bracelet</strong>.Let's relax, kick back and enjoy some instant reveals, interesting http://www.ecocoachoutletonline.com <strong>coach outlet</strong>, and so much more!If you're wary of overkill go for a sheer texture. Leave matte formulas for the young, but a touch of gloss adds a modern touch. If that doesn't indicate a close, personal friendship betwixt celeb <strong>chan luu necklace</strong>, then what does, exactly?&quot;Coach outlet is this part of http://www.usitccoachpurses.com culture with a certain timelessness to coach purses outlet.&quot; Sure, when you cross a line into preventing others from getting what they want, then absolutely, reassess your <strong>cheap coach purses</strong>, but too many coach outlet stores are scared to go after what they want for fear of rocking the boat with others.We hope your <strong>chan luu</strong> bracelet is ready;. And we're not sure if this is a ilovechanluu creation or just one of those cheap coach purses you can get for a tenner off the market, but that's looking like one designer patch at the <strong>chan luu sale</strong>!The purses come in three sizes, but one thing that stays the same is the length of the leather coach purses-- hand braided in USA. </p>

somanabolic muscle maximizer scam 2013-09-11 09:18:06

If you want free info About Somanabolic Muscle Maximizer Scam how to achieve such a physique, please visit my website at=>> Somanabolic Muscle Maximizer Scam