4 ms·

They may appear to be returning a fresh copy, but internally much of the structure is shared rather than copied. See Persistent data structure: http://en.wikipe

They may appear to be returning a fresh copy, but internally much of the structure is shared rather than copied. See Persistent data structure: http://en.wikipedia.org/wiki/Persistent_data_structure http://en.wikipedia.org/wiki/Persistent_data_structure

TylerE 13y ago
Much is shared, yes, but compared to a traditional approach with static arrays, there is a _lot_ of copying in a typical FP approach.
- mercurial 13y ago
  Sure, but in Haskell, a lot of it will be deforested by the compiler.