-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Generate Graphviz documents from a Haskell representation.
--   
@package dataflow
@version 0.4.2.0

module DataFlow.Core

-- | An identifier corresponding to those in Graphviz.
type ID = String

-- | The name of a <a>Diagram</a> or <a>Object</a>.
type Name = String

-- | Operation heading.
type Operation = String

-- | Operation description.
type Description = String

-- | The top level diagram.
data Diagram
Diagram :: Name -> [Object] -> Diagram

-- | An object in a diagram.
data Object

-- | A <a>Input</a> or <a>Output</a> in DFD.
InputOutput :: ID -> Name -> Object

-- | Surrounds other objects, denoting a boundary.
TrustBoundary :: ID -> Name -> [Object] -> Object

-- | A "Function" in DFD.
Function :: ID -> Name -> Object

-- | A "Database" in DFD.
Database :: ID -> Name -> Object

-- | Describes the flow of data between two objects.
Flow :: ID -> ID -> Operation -> Description -> Object

-- | The Renderer represents some output generator that runs on a
--   <a>Diagram</a>.
type Renderer t = WriterT [String] (State RendererState) t

-- | Run the <a>Renderer</a> and get the output as a <a>String</a>.
evalDiagram :: Renderer () -> String

-- | Write a string to the output (no linefeed).
write :: String -> Renderer ()

-- | Write a string to the output (with linefeed).
writeln :: String -> Renderer ()

-- | Get the next "step" number (the order of flow arrows in the diagram).
nextStep :: Renderer Int

-- | Increase indent with 2 spaces.
indent :: Renderer ()

-- | Decrease indent with 2 spaces.
dedent :: Renderer ()

-- | Indent the output of gen with 2 spaces.
withIndent :: Renderer () -> Renderer ()

-- | Write a blank line.
blank :: Renderer ()

-- | Write a label with the output of gen as its contents.
label :: Renderer () -> Renderer ()

-- | Write an HTML tag t with the output of gen as its contents.
tag :: String -> String -> Renderer () -> Renderer ()

-- | Write a &lt;b&gt; tag surrounding the output of another
--   <a>Renderer</a>.
bold :: Renderer () -> Renderer ()

-- | Write a &lt;table&gt; tag, with attributes, surrounding the output of
--   another <a>Renderer</a>.
table :: String -> Renderer () -> Renderer ()

-- | Write a &lt;tr&gt; tag surrounding the output of another
--   <a>Renderer</a>.
tr :: Renderer () -> Renderer ()

-- | Write a &lt;td&gt; tag surrounding the output of another
--   <a>Renderer</a>.
td :: Renderer () -> Renderer ()

-- | The enclosing characters in a block.
data Enclosing
Brackets :: Enclosing
CurlyBrackets :: Enclosing

-- | Write an object with the given <a>Enclosing</a> characters, <a>ID</a>
--   and <a>Renderer</a> as its contents.
objectWith :: Enclosing -> ID -> Renderer () -> Renderer ()

-- | Write an attributes declaration for the given <a>ID</a>.
attrs :: ID -> String -> Renderer ()
instance Show Object
instance Eq Object

module DataFlow.DFD
type DFDState v = State (Map (ID, ID) Bool) v
type DFDRenderer t = DFDState (Renderer t)

-- | Type class for types that can be rendered as DFD.
class RenderDFD t
dfd :: RenderDFD t => t -> DFDRenderer ()
return' :: t -> DFDRenderer t
exists :: (ID, ID) -> DFDState Bool
register :: (ID, ID) -> DFDState ()
shouldInvert :: (ID, ID) -> DFDState Bool

-- | Generates the DFD output as a String.
evalDfd :: Diagram -> String

-- | Prints the DFD output to stdout.
printDfd :: Diagram -> IO ()
instance RenderDFD Diagram
instance RenderDFD Object