CoffeeScript is 4 times shorter than C

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.