To build Fregel compiler, read compiler/README.

Some sample Fregel programs are found in sample-programs directory:

  ds.fgl     ... Densest subgraph computation.
  gmaxv.fgl  ... Every vertex finds the maximum among all vertices.
  maxv.fgl   ... Every vertex finds the maximum among its reachable vertices.
  re.fgl     ... Reachability computation.
  sssp.fgl   ... Single source shortest path (from vertex 1)
  sssp2.fgl  ... Single source shortest path (from vertex 1) (another version)

  graph4.txt ... A small graph for Giraph (graph4 in Graphs.hs)


Haskell implementation of Fregel for debugging is found in haskell directory:

  Fregel.hs  ... Haskell implementation of Fregel (for debugging)
  Graphs.hs  ... Sample graphs and utilities
  
  ds.hs      ... For running ds.fgl on Haskell
  maxv.hs    ... For running maxv.fgl on Haskell
  re.hs      ... For running re.fgl on Haskell
  sssp.hs    ... For running sssp.fgl on Haskell
  sssp2.hs   ... For running sssp2.fgl on Haskell


Current limitation:

  Haskell's off-side rule is not implemented yet. You need to separate
  bindings in a let-expression by semicolon. A new parser is now being
  implemented.

  The type of vertex values in the input graph is assumed to be Integer.