Saturday, March 08, 2008

No big deal?

Have you ever done something "obvious" and later discovered that it's the topic of a famous paper, or something that gets put in the "advanced" section of the textbooks?

I just read the wikipedia article on tail recursion, and got a surprise when I read the last section.

I've always implemented lists in C along these lines:

void insert(list_t** list, int idx, list_t* item)
while(*list && idx--)
list = &(*list)->next;
item->next = *list;
*list = item;

Now to me, this is pretty obvious stuff. But it turns out to have a name - "tail recursion modulo cons" - and credit for its invention goes to David H. D. Warren. Go figure.

I have to ask, though - are our standards getting higher so fast that an advanced concept from twenty years ago is now not worth mentioning?


Blogger david santos said...

Hello, David!
Thanks for your posting and have a good weekend

5:28 PM  
Blogger David Turner said...

Thanks for commenting, David :)

It's nice to know someone reads this stuff...

12:08 PM  

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