Compare FreeBSD’s sed.c (implemented in C) with drj’s sed.js (implemented in CoffeeScript).
A size comparison
lines bytes
C 2471 62k
CoffeeScript 533 14k
That right there is CoffeeScript’s chief advantage over C. The CoffeeScript is 4 times smaller, meaning CoffeeScript programs are likely to be faster to write, easier to maintain, and contain fewer bugs.
Is it an apples to apples comparison? The FreeBSD sed implements a couple more options than my mostly POSIX compliant sed.js but they don’t pad it out much. Neither implementation includes code to handle Regular Expressions. sed.c uses the Unix library and sed.coffee uses JavaScript’s built-in RegExp class. So I think it’s a pretty reasonable comparison.
What makes the C code bigger? There is a lot of memory management, and an awful lot of string copying and substring extraction. There is an implementation of a hash table (for labels).
Obviously we all knew that high level languages resulted in smaller programs, but it’s rare to get the opportunity to do such a direct comparison.
code monk 
2013-08-31 at 21:09:06
But how short would it be in J?
2013-09-02 at 08:33:43
Well, it’s only one line in shell. Let’s write our next web templating engine in shell then! (done that: html escaping is already a nightmare in such an environment)
What you should look at is code complexity for realistic applications written in JS, like user interfaces: a simple UI to interface with a database, or compute some values. C would drown itself in extra lines to keep it readable, and because of its lack of automatic memory management. C++ would already be a lot better.
2013-09-02 at 19:12:48
I don’t think that’s an “Apples to Apples” comparison :)