Lecture 2A | MIT 6.001 Structure and Interpretation, 1986

[NewKeepSharing31]

keep spirit MIT :D

[pjojin0]

Thanks for the great video

[TheSanovita]

Very awesome

[MyDavidsun]

awesome

[andreeaweed]

thanks for the video!!

[iateyourgranny]

but b wasn't defined in the iterative implementation of SUM, or was it?

[YouDabian]

@iateyourgranny "b" is the ubber bound, its just a number.

[YouDabian]

@YouDabian *upper

[iateyourgranny]

@YouDabian uh-huh, and where is its value defined?

[YouDabian]

@iateyourgranny Just like a, which is not assigned a value either, Its a formal parameter of sum. It will be difined when you call sum. For instance: (sum-int 1 5) will evaluate to 1+2+3+4+5 == 15. (In this case, a will be 1 and b will be 5).

[YouDabian]

@iateyourgranny It seems like you're right there. I think the definition is wrong, instead of:

(define (sum term a next) ...

It probably should have been:

(define (sum term a next b) ...

Like the recursive version.

[ngeliatduit]

Mantap, Good Video!!

[karimfaidh]

It's great



[Flusercom]

good video, very informative

[Spasatcom]

Nice video Thumb up

[DroidooNetwork]

It's funny to see just how little has changed since 1986 to present time as far as general structure goes.

[felipecotti]

I absolutely love how that last dude, after being answered by The Sussman, enters in a deep, deep meditation as the camera zooms off. He is totally immersed in the universe, and the universe is becoming one with him; he had a glimpse of reaching Satori.

[DovletTatlok]

Thumb up if you see a bug in the listing at 19:00

[eatme690808]

Thank you MIT for posting such quality material. Even though this is 25 years old, going over this material is still incredibly illuminating.

[mahcuz]

Damn sound quality!

[KillaHaakon]

It's hilarious how easy it is to translate this into Prolog.

Perhaps they are secret fans?

Also, thanks for showing a secret (dirty) way of doing loops recursively. :D

[tcrayford]

Look up drscheme, and then google for sicp for drscheme and download/install that

[chiefthegreat]

Does anyone know a lisp-compiler that runs on a today linux, which can actually work like that ?

I just find that it's not replicable anymore: Have maybe 6 lisp's here, and none of them really works ...

[Dynamics18]

search MIT Scheme

maybe you will get something. =)?

[chiefthegreat]

I had tried that out ... ; also didn't fully work (and I wondered about that, since this here is MIT too) . Now I'm at standard common lisp (SBCL); maybe I give another try to the MIT-scheme ... :

Which one gives more freedom to the programmer ?

[KillaHaakon]

@chiefthegreat

Did tcrayford's suggestion work?

So far I've just used prolog, and I'd like to use LISP, as they aren't really the same at all. (They have similar syntax though)

[chiefthegreat]

Actually then I gave a second try to mit-scheme, and found that it actually works; I prefer this now and have done useful stuff with it already too ...

But I found a hack on the net to use vi (and the screen-program) instead of the emacs-editor, to emulate some sort of slime-like environment; that made part of the difference ...;

seems to be quite some good language ! (mit-scheme)

[oakenshield1]

The code shown in these videos perfectly run on MIT Scheme. This is Scheme dialect of Lisp not Common Lisp.

[chiefthegreat]

Yes, your'e right; I verified that then too ... .

Anyhow the built-in editor keeps you from beeing productive; that's why I use "vi" and "screen" to work around ...

[KillaHaakon]

@chiefthegreat

Heathen!

Emacs is superior! :p

Anyway, thanks for clearing this up, I can now Scheme happily. If you like the Lisp syntax, and want to check out other interesting languages, I highly recommend Prolog.

The SWI-Prolog is free software, and can be found on their webpage.

[eatme690808]

@chiefthegreat You can sudo apt-get install mit-scheme from a Ubuntu related distro and it works perfectly.  That interpreter should be available on many flavors or Linux.