What's an example of Ruby code that's “too clever”? [closed]

Answer 1

compare:

if MODELS.keys.inject(true) {|b, klass| b and klass.constantize.columns.map(&:name).include? association.options [:foreign_key]} then 
  # ... 
end

1 line (if), 132 chars, 132 avg len, 22.9 flog

vs

fk = association.options[:foreign_key] 
columns = MODELS.keys.map { |key| key.constantize.columns.map { |c| c.name } } 
if columns.all? {|column| column.include? fk} then 
  # ... 
end

4 lines, 172 chars, 43 avg chars, 15.9 flog

much faster too.

Original author actually argued maintainability for the first version.

Answer 2

The output phase of yaml.rb; that's why I co-authored zaml.rb. The standard yaml version does all sorts of metaprogramming (it was originally written by why-the-lucky-stiff, who I generally admire) but by replacing it with a straight forward hierarchical version that directly maps to the class tree we were able to eliminate several O(n^3) cases, resulting in a factor of ten speedup for cases of interest, fix several bugs, and do so in a fraction of the code.

Plus, even people who aren't ruby gurus can see what it does.