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


-- | tiny calculator library and command-line program
--   
--   a library and a command-line program for calculating numeral
--   expressions with infix operators and constants but without
--   parantheses.
@package hascal
@version 3.0.1


-- | Hascal is a simple, minimalistic, tiny calculator library and program.
--   
--   <ul>
--   <li>Hascal only understands single-character operators.</li>
--   <li>Hascal only understands infix operators.</li>
--   <li>Hascal does not understand parantheses.</li>
--   <li><tt>_</tt> is hard-coded as single prefix for negating
--   numbers.</li>
--   <li>By default, Hascal understands the operators <tt>+</tt>,
--   <tt>-</tt>, <tt>*</tt>, <tt>/</tt>, <tt>^</tt>, and <tt>?</tt>
--   (logarithm).</li>
--   <li>By default, Hascal understands the constants <tt>pi</tt>,
--   <tt>e</tt>, and <tt>i</tt>.</li>
--   <li>Using Hascal as a library, you can add new operators and new
--   constants using a configuration data type.</li>
--   </ul>
--   
--   The hascal executable program is easy to use. In a shell, type:
--   
--   <pre>
--   &gt;&gt;&gt; hascal 1+2-3*4/5^6?7
--   -1.7263530417152033
--   </pre>
--   
--   Given a configuration, the <a>hascal</a> function similarly evaluates
--   an expression of type <a>String</a>. In a Haskell interpreter like
--   GHCI, type:
--   
--   <pre>
--   &gt;&gt;&gt; hascal def "1+2-3*4/5^6?7"
--   Right (0.2736469582847967 :+ 0.0)
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; hascal def "1++2"
--   Left "Error at \"\"."
--   </pre>
module Hascal

-- | A configuration. <a>def</a> is the default configuration.
data Config t
Config :: [Operator t] -> [Constant t] -> Config t

-- | A list of operators. The order in this list also determines the order
--   of evaluation.
[operators] :: Config t -> [Operator t]

-- | A list of constants.
[constants] :: Config t -> [Constant t]

-- | A class for types with a default value.
class Default a

-- | The default value for this type.
def :: Default a => a

-- | Given a configuration and a <a>String</a>-expression, returns
--   <a>Either</a> a <a>String</a> containing an error message; or a
--   <a>Complex</a> number.
hascal :: (Read t, RealFloat t) => Config t -> String -> Result t

-- | Given a configuration and a <a>String</a>-expression, returns a
--   <a>String</a> containing the error message or the resulting complex
--   number.
showHascal :: (Show t, Read t, RealFloat t) => Config t -> String -> String

-- | Show a <a>Complex</a> number a little bit more human-readable by
--   matching both the real and the imaginery part against zero and one.
showNumber :: (Show t, RealFloat t) => Complex t -> String
instance (GHC.Read.Read t, GHC.Float.RealFloat t) => Data.Default.Class.Default (Hascal.Config t)