Finally remove unused files from source control

This commit is contained in:
Evan Czaplicki 2014-03-08 08:33:37 -08:00
parent 142c2c0261
commit 1f6fdd808b
2 changed files with 0 additions and 272 deletions

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module Automaton ( pure, state, hiddenState, run, step
, (<<<), (>>>), combine, count, average
) where
{-| This library is a way to package up dynamic behavior. It makes it easier to
dynamically create dynamic components. See the [original release
notes](http://elm-lang.org/blog/announce/0.5.0.elm) on this library to get a feel for how
it can be used.
# Create
@docs pure, state, hiddenState
# Evaluate
@docs run, step
# Combine
@docs (>>>), (<<<), combine
# Common Automatons
@docs count, average
-}
import open Basics
import Signal (lift,foldp,Signal)
import open List
import Maybe (Just, Nothing)
data Automaton a b = Step (a -> (Automaton a b, b))
{-| Run an automaton on a given signal. The automaton steps forward whenever the
input signal updates.
-}
run : Automaton a b -> b -> Signal a -> Signal b
run auto base inputs =
let step a (Step f, _) = f a
in lift (\(x,y) -> y) (foldp step (auto,base) inputs)
{-| Step an automaton forward once with a given input. -}
step : a -> Automaton a b -> (Automaton a b, b)
step a (Step f) = f a
{-| Compose two automatons, chaining them together. -}
(>>>) : Automaton a b -> Automaton b c -> Automaton a c
f >>> g =
Step (\a -> let (f', b) = step a f
(g', c) = step b g
in (f' >>> g', c))
{-| Compose two automatons, chaining them together. -}
(<<<) : Automaton b c -> Automaton a b -> Automaton a c
g <<< f = f >>> g
{-| Combine a list of automatons into a single automaton that produces a
list.
-}
combine : [Automaton a b] -> Automaton a [b]
combine autos =
Step (\a -> let (autos', bs) = unzip (map (step a) autos)
in (combine autos', bs))
{-| Create an automaton with no memory. It just applies the given function to
every input.
-}
pure : (a -> b) -> Automaton a b
pure f = Step (\x -> (pure f, f x))
{-| Create an automaton with state. Requires an initial state and a step
function to step the state forward. For example, an automaton that counted
how many steps it has taken would look like this:
count = Automaton a Int
count = state 0 (\\_ c -> c+1)
It is a stateful automaton. The initial state is zero, and the step function
increments the state on every step.
-}
state : b -> (a -> b -> b) -> Automaton a b
state s f = Step (\x -> let s' = f x s
in (state s' f, s'))
{-| Create an automaton with hidden state. Requires an initial state and a
step function to step the state forward and produce an output.
-}
hiddenState : s -> (a -> s -> (s,b)) -> Automaton a b
hiddenState s f = Step (\x -> let (s',out) = f x s
in (hiddenState s' f, out))
{-| Count the number of steps taken. -}
count : Automaton a Int
count = state 0 (\_ c -> c + 1)
type Queue t = ([t],[t])
empty = ([],[])
enqueue x (en,de) = (x::en, de)
dequeue q = case q of
([],[]) -> Nothing
(en,[]) -> dequeue ([], reverse en)
(en,hd::tl) -> Just (hd, (en,tl))
{-| Computes the running average of the last `n` inputs. -}
average : Int -> Automaton Float Float
average k =
let step n (ns,len,sum) =
if len == k then stepFull n (ns,len,sum)
else ((enqueue n ns, len+1, sum+n), (sum+n) / (toFloat len+1))
stepFull n (ns,len,sum) =
case dequeue ns of
Nothing -> ((ns,len,sum), 0)
Just (m,ns') -> let sum' = sum + n - m
in ((enqueue n ns', len, sum'), sum' / toFloat len)
in hiddenState (empty,0,0) step
{-- TODO(evancz): See the following papers for ideas on how to make this
library faster and better:
- Functional Reactive Programming, Continued
- Causal commutative arrows and their optimization
Speeding things up is a really low priority. Language features and
libraries with nice APIs and are way more important!
--}

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module AutomatonV2 where
{-| This library is a way to package up dynamic behavior. It makes it easier to
dynamically create dynamic components. See the [original release
notes](/blog/announce/version-0.5.0.elm) on this library to get a feel for how
it can be used.
-}
import open Basics
import Signal (lift,foldp,Signal)
import open List
import Maybe (Just, Nothing)
data Automaton input output = Pure (input -> output)
| Stateful state (input -> state -> (output,state))
-- The basics
-- AFRP name: arr
pure: (i -> o) -> Automaton i o
pure = Pure
-- AFRP name: >>>
andThen: Automaton i inter -> Automaton inter o -> Automaton i o
andThen first second =
case first of
Pure f -> case second of -- f is the function from first
Pure s -> Pure (s . f) -- s is the function from second
Stateful b s -> Stateful b (\i -> s (f i)) -- b is the base state from second
Stateful fb f -> case second of -- fb is the base state from first
Pure s -> Stateful fb (\i st -> -- sb is the base state from second
let (inter, st') = f i st -- i is the input
in (s inter, st')) -- st is the input state
Stateful sb s -> Stateful (fb, sb) (\i (fst, sst) -> -- inter is the intermediate value
let (inter, fst') = f i fst -- st' is the new state
(o, sst') = s inter sst -- fst and sst are the state of first and second
in (o, (fst', sst'))) -- ect...
-- AFRP name: first
extendDown: Automaton i o -> Automaton (i,extra) (o,extra)
extendDown auto = case auto of
Pure fun -> Pure (\(i,extra) -> (fun i, extra))
Stateful base fun -> Stateful base (\(i,extra) s -> (fun i s, extra))
-- AFRP name: loop
loop: s -> Automaton (i,s) (o,s) -> Automaton i o
loop base auto = case auto of
Pure fun -> Stateful base (curry fun)
Stateful base2 fun -> -- fun: (i, s) -> s2 -> ((o, s), s2)
let newFun = (\i (s,s2) ->
let ((o, s'), s2') = fun (i, s) s2
in (o, (s', s2'))) -- newFun: i -> (s, s2) -> (o, (s, s2))
in Stateful (base, base2) newFun
-- Run an automaton on a given signal
run: Automaton i o -> o -> Signal i -> Signal o
run auto baseOut input = case auto of
Pure fun -> lift fun input
Stateful base fun -> lift fst
(foldp (\i (o, s) -> fun i s)
(baseOut, base) input)
-- Other frequently used functions/operators
-- Create an automaton with state. Requires an initial state and a step
-- function to step the state forward. For example, an automaton that counted
-- how many steps it has taken would look like this:
--
-- count = Automaton a Int
-- count = state 0 (\\_ c -> c+1)
--
-- It is a stateful automaton. The initial state is zero, and the step function
-- increments the state on every step.
state : s -> (i -> s -> s) -> Automaton i s
state base fun = loop base (pure (\(i,s) ->
let s' = fun i s
in (s',s')))
-- Create an automaton with hidden state. Requires an initial state and a
-- step function to step the state forward and produce an output.
hiddenState : s -> (i -> s -> (s,o)) -> Automaton i o
hiddenState base fun = loop base (pure (\(i,s) ->
let (o,s') = fun i s
in (s',o)))
-- AFRP name: second
extendUp: Automaton i o -> Automaton (extra,i) (extra,o)
extendUp auto =
let swap (a, b) = (b, a)
in pure swap `andThen` extendDown auto `andThen` pure swap
-- (parallel composition)
pair: Automaton i1 o1 -> Automaton i2 o2 -> Automaton (i1,i2) (o1,o2)
pair f g = extendDown f `andThen` extendUp g
branch : Automaton i o1 -> Automaton i o2 -> Automaton i (o1,o2)
branch f g =
let double = pure (\i -> (i,i))
in double `andThen` pair f g
combi: Automaton i o -> Automaton i [o] -> Automaton i [o]
combi a1 a2 = (a1 `branch` a2) `andThen` pure (uncurry (::))
-- Combine a list of automatons into a single automaton that produces a list.
combine : [Automaton i o] -> Automaton i [o]
combine autos =
let l = length autos
in if l == 0
then pure (\_ -> [])
else foldr combi (last autos `andThen` pure (\a -> [a])) (take (l-1) autos)
-- Examples of automata
-- Count the number of steps taken.
count : Automaton a Int
count = state 0 (\_ c -> c + 1)
type Queue t = ([t],[t])
empty = ([],[])
enqueue x (en,de) = (x::en, de)
dequeue q = case q of
([],[]) -> Nothing
(en,[]) -> dequeue ([], reverse en)
(en,hd::tl) -> Just (hd, (en,tl))
-- Computes the running average of the last `n` inputs.
average : Int -> Automaton Float Float
average k =
let step n (ns,len,sum) =
if len == k then stepFull n (ns,len,sum)
else ((enqueue n ns, len+1, sum+n), (sum+n) / (toFloat len+1))
stepFull n (ns,len,sum) =
case dequeue ns of
Nothing -> ((ns,len,sum), 0)
Just (m,ns') -> let sum' = sum + n - m
in ((enqueue n ns', len, sum'), sum' / toFloat len)
in hiddenState (empty,0,0) step
{-- TODO(evancz): See the following papers for ideas on how to make this
library faster and better:
- Functional Reactive Programming, Continued -- took some inspirations from this paper (Apanatshka)
- Causal commutative arrows and their optimization
Speeding things up is a really low priority. Language features and
libraries with nice APIs and are way more important!
--}