3 ms·

Alligator Eggs and Lambda Calculus (2007)

29 points by veqq 2y ago

deleted 2y ago
[deleted]
Jtsummers 2y ago
Some past discussions. I thought it had been discussed more but maybe it turned up in other discussions rather than as a submission of its own. https://news.ycombinator.com/item?id=8906167 https://news.ycombinator.com/item?id=8906167 - Jan 18, 2015 (24 comments) https://news.ycombinator.com/item?id=4586692 https://news.ycombinator.com/item?id=4586692 - Sept 28, 2012 (24 comments) https://news.ycombinator.com/item?id=600736 https://news.ycombinator.com/item?id=600736 - May 9, 2009 (9 comments)
bitwize 2y ago
I always thought this was up there with "monads are like burritos" in terms of how it makes things more complicated instead of simplifying them. Maybe that's just my old ass, and kids would appreciate it more. When I was a kid one of my teachers referred to the > and < symbols as "alligator mouths" and said "Just remember the alligator mouth eats the bigger number." Helped me keep those symbols straight for years.
- gs17 2y ago
  Yeah, I "get" it, but I can only think that as a kid I would have been too upset about all the senseless alligator deaths to internalize the patterns. I guess if they're not old enough to know algebra, (λx.x λy.y)(λz.z) might be more scary than a reptilian predator.
  - bitwize 2y ago
    The thing that made me grok lambda calculus was someone[0] in a tutorial online treated as a simple substitution game. They said: Imagine "λx.chocolate covered x" is a lambda expression, and if you apply that to "peanuts" you get "chocolate covered peanuts" and if you apply it to "ants" you get "chocolate covered ants". I knew at that time that LAMBDA was an operator for creating "anonymous functions" in Lisp you could pass to MAP or APPLY, but the "chocolate covered" thing was what made the penny drop that in pure LC, a lambda is just a template with a variable, and application (beta reduction) is substituting values for variables in the templates. [0] It was probably Jim Larson: https://www.cs.unc.edu/~stotts/COMP204/Lambda/scheme.html https://www.cs.unc.edu/~stotts/COMP204/Lambda/scheme.html
    - southpawflo 2y ago
      thanks for the link, I enjoyed reading that
  - selimthegrim 2y ago
    I suppose birds are a kind of reptile if they like reading Smullyan.
- laszlokorte 2y ago
  Thats exactly how my teacher in second grade when I was 8 years old (in Germany) taught us about greater than ans less than.
876978095789789 2y ago
[dead]
scotty79 2y ago
This post many years ago made me realize that there's nothing uniquely interesting about lambda calculus. That it's just weird, convoluted virtual machine that can be (barely) used for programming.

29 points by veqq 2y ago

deleted 2y ago

[deleted]

Some past discussions. I thought it had been discussed more but maybe it turned up in other discussions rather than as a submission of its own. https://news.ycombinator.com/item?id=8906167 https://news.ycombinator.com/item?id=8906167 - Jan 18, 2015 (24 comments) https://news.ycombinator.com/item?id=4586692 https://news.ycombinator.com/item?id=4586692 - Sept 28, 2012 (24 comments) https://news.ycombinator.com/item?id=600736 https://news.ycombinator.com/item?id=600736 - May 9, 2009 (9 comments)

bitwize 2y ago

I always thought this was up there with "monads are like burritos" in terms of how it makes things more complicated instead of simplifying them. Maybe that's just my old ass, and kids would appreciate it more. When I was a kid one of my teachers referred to the > and < symbols as "alligator mouths" and said "Just remember the alligator mouth eats the bigger number." Helped me keep those symbols straight for years.

gs17 2y ago
Yeah, I "get" it, but I can only think that as a kid I would have been too upset about all the senseless alligator deaths to internalize the patterns. I guess if they're not old enough to know algebra, (λx.x λy.y)(λz.z) might be more scary than a reptilian predator.
- bitwize 2y ago
  The thing that made me grok lambda calculus was someone[0] in a tutorial online treated as a simple substitution game. They said: Imagine "λx.chocolate covered x" is a lambda expression, and if you apply that to "peanuts" you get "chocolate covered peanuts" and if you apply it to "ants" you get "chocolate covered ants". I knew at that time that LAMBDA was an operator for creating "anonymous functions" in Lisp you could pass to MAP or APPLY, but the "chocolate covered" thing was what made the penny drop that in pure LC, a lambda is just a template with a variable, and application (beta reduction) is substituting values for variables in the templates. [0] It was probably Jim Larson: https://www.cs.unc.edu/~stotts/COMP204/Lambda/scheme.html https://www.cs.unc.edu/~stotts/COMP204/Lambda/scheme.html
  - southpawflo 2y ago
    thanks for the link, I enjoyed reading that
- selimthegrim 2y ago
  I suppose birds are a kind of reptile if they like reading Smullyan.
laszlokorte 2y ago
Thats exactly how my teacher in second grade when I was 8 years old (in Germany) taught us about greater than ans less than.

876978095789789 2y ago

[dead]

scotty79 2y ago

This post many years ago made me realize that there's nothing uniquely interesting about lambda calculus. That it's just weird, convoluted virtual machine that can be (barely) used for programming.