Add circuit build function

Circuit.hs

@@ -5,6 +5,12 @@ import Data.List
 
 type Nat = Int
 
+-- IMPORANT functions:
+-- * build
+--   create a circuit for a desired fuel output
+-- example:
+--   build key
+
 -- Circuit Syntax:
 -- <inPin>:[<gates>]:<outPin>
 -- each Pin is either "X" (circuit IN or OUT)
@@ -42,6 +48,22 @@ test0 = fact0_output == execcirc factory0
 -- known server input stream (from factory "X::X")
 input = readstream "01202101210201202"
 
+block0 = 0:(init input)
+block1 = 1:(init input)
+block2 = 2:(init input)
+
+-- basic blocks
+-- 0: 1R:2L1L0#X2L,2RX0#0R2R,0R1R0#0L1L:0L
+-- 1: 2L:2R1R0#2R1R,2L0R0#X0R,X0L0#1L0L:1L
+-- 2: 2R:2R1R0#2L1L,0R2L0#X0R,0LX0#1R0L:1L
+-- build circuit for needed output
+build s = let (p, pins) = step (-1) [] (reverse s) in Circuit p pins where
+	step p gates [] = (p, gates)
+	step p gates (x:xs) = let k = length gates in case x of
+		0 -> step k (gates ++ [k+4,k+2,k+5,p,k+1,k+3]) xs
+		1 -> step (k+2) (gates ++ [k+5,k+3,k+4,k+1,p,k]) xs
+		2 -> step (k+2) (gates ++ [k+5,k+3,k+1,k+4,k,p]) xs
+
 data Circuit = Circuit { outPin :: Int, inPins :: [Int] } deriving (Eq)
 
 instance Show Circuit where