HACKING

Compilation phases (by sub-directories of "src"):
  1) parsing:
    * Transforms the source file into an AST
  2) desugaring:
    * Decomposes syntactic sugars from the parse-tree
  3) pre-typing:
    * Fixes the type of recursive values (mandatory)
    * Check that recursive values are not referenced before the first abstraction (forbidden/unsafe)
  4) typing:
    * Type-checks everything (we don't need types anymore after that)
    * Compile pattern matching using Maranget's algorithm: http://moscova.inria.fr/~maranget/papers/ml05e-maranget.pdf
  5) lambda:
    * Gives a unique name to all values (LIdent + Lambda.scan)
    * Encode variants and foreign declarations
    * Introduces lets instead of recursing over the AST
  6) flatten:
    * Set all lets to the same level for each function (no nested lets)
    * Propagate abstractions to applications [a = (λx.t); b = a y] --> [x = y; a = (λx.t); b = t]
    * Propagate names [a = b; c = a] --> [c = b]
  7) optimization:
    * Fixes free variables on λ-abstractions
  8) backend:
    * Transforms AST to LLVM-IR using:
      * setjmp/longjmp to encode exceptions
      * one-argument functions to encode lambdas