CS 61A Lecture 4: Higher-Order Procedures

[Argcz]

I love how empty the classroom compared to week1 vid lol :)

[ArchSaur]

Dumb syntax is first problem you get here, everything else seems actually simple to me. Why can't  let ((N1 V1) (N2 V2) ... (Nn Vn)) have syntax like let {N1:V1; N2:V2; ... Nn:Vn}. Why create all that mess with "different kind of parenthesis"?..

[apilash]

what language is good to start with? please reply :d

[harleybristowabc]

@apilash Java

[ArchSaur]

@apilash BASIC (-:

[banzaimonkey]

The example code is written in Scheme. The functions described on the board between 4:05 and 7:30 correspond to Python's map (every), filter (keep), and reduce (accumulate), which are also designed to work with lambda functions.

[weedipikia]

Lambda Lambda Lambda and Omega Mu

[TheNefski]

Regarding a talk on 42:04 sec. Is this correct solution?

((lambda (x fn)

(fn x fn))

10000 (lambda (x fn)

(if (= x 0)

1

(* (fn (- x 1) fn) x))))

Works quite fine with 10000 (less then sec) gives nice looking long result. Fails with 100000 (Segmentation fault).

[anantnewbie]

@TheNefski Brilliant!

[xssive405]

@TheNefski That's neat. Encapsulating the lambda within a lambda in order to label the function fn. Seems like the most direct approach. I wouldn' t have thought it up, but I've been watching all 4 videos straight in a row :) Which might be a bit too much at once.

[xssive405]

@xssive405 By the by: On me NetBSD system with Gambit-C as scheme environment it does 100000 with no problems.

[MrNefski]

@xssive405, Thanks, to say the true, decision came intuitively. I was watching one per day, as I remember. I've got purple book of wisdom, but have not enough time and energy to study, now... sad, but true.

[aaronarmstrongskomra]

The contents of lectures 5 and 6 is a video lecture by Alan Key - it is also available at the internet archive (in better quality) under the titles "AlanKeyD1987" and "AlanKeyD1987_2"

Lecture 7 is a regular lecture. I have no idea why it is marked private.

[rycemuffin]

thanks

[ogrish84]

Why have some of these been made private?!

[tbarker5252]

Random thank you so much bro!

[random2929]

Lectures 5, 6, and 7 are marked private. You can find them in Real video and MP3 formats via Google search for "webcast cs61a spring 2008"

[many1977]

great, but y other videos are private? Berkeley wants to use public services for own students ?