Deforestation (computer science)

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In the theory of programming languages in computer science, deforestation (also known as fusion) is a program transformation to eliminate intermediate lists or tree structures that are created and then immediately consumed by a program.

The term "deforestation" was originally coined by Philip Wadler in his 1990 paper "Deforestation: transforming programs to eliminate trees".[1]

Deforestation is typically applied to programs in functional programming languages, particularly non-strict programming languages such as Haskell. One particular algorithm for deforestation, shortcut deforestation,[2] is implemented in the Glasgow Haskell Compiler.[3] Deforestation is closely related to escape analysis.

See also[edit]


  1. ^ Wadler, Philip (1990). "Deforestation: transforming programs to eliminate trees". Theoretical Computer Science. 73 (2): 231–248. doi:10.1016/0304-3975(90)90147-A.
  2. ^ Gill, Andrew; John Launchbury; Simon Peyton Jones (1993). "A short cut to deforestation" (PDF). Proc. Conf. on Functional Programming Languages and Computer Architecture. pp. 223–232. doi:10.1145/165180.165214.
  3. ^ Peyton Jones, Simon; Andrew Tolmach; C.A.R. Hoare (2001). "Playing by the rules: rewriting as a practical optimization technique in GHC" (PDF). Proc. ACM/SIGPLAN Haskell Workshop.