[Haskell-cafe] Basic Parsec float integer parsing question

2013-07-05 Thread Fredrik Karlsson 
Dear list,

Sorry for asking a simple parsec question, but both Parsec and Haskell is
new to me, so please be gentle :-)

I have this code:


import Text.ParserCombinators.Parsec
import Text.Parsec.Token
import Text.ParserCombinators.Parsec.Char


data VariableLine = VariableLine String String deriving Show
data TierType = IntervalTier | PointTier deriving Show

data Tier = Tier TierType String Float Float Integer
data Label = Interval Float Float String
data LabelFile = LabelFile Float Float

symbol :: Parser Char
symbol = oneOf !#$%|*+-/:=?@^_~

testString = intervals [1]:\nxmin = 0 \nxmax =
0.028192 \ntext = \\
headTS1 = File type = \ooTextFile\\nObject class = \TextGrid\\n\nxmin
=

header :: Parser LabelFile
header = do
headTS1
start - float
string \nxmax = 
end - float
string \ntiers? exists\nsize = 
integer
char '\n'
return $ LabelFile start end



Loading it into ghci I get :

Prelude :l parsectest.hs
[1 of 1] Compiling Main ( parsectest.hs, interpreted )

parsectest.hs:21:9:
Couldn't match type `[]'
  with `Text.Parsec.Prim.ParsecT
  String () Data.Functor.Identity.Identity'
Expected type: Text.Parsec.Prim.ParsecT
 String () Data.Functor.Identity.Identity Char
  Actual type: [Char]
In a stmt of a 'do' block: headTS1
In the expression:
  do { headTS1;
   start - float;
   string
 \
 \xmax = ;
   end - float;
    }
In an equation for `header':
header
  = do { headTS1;
 start - float;
 string
   \
   \xmax = ;
  }

parsectest.hs:22:18:
Couldn't match expected type `Text.Parsec.Prim.ParsecT
String ()
Data.Functor.Identity.Identity Float'
with actual type `GenTokenParser s0 u0 m0
  - Text.Parsec.Prim.ParsecT s0 u0 m0
Double'
In a stmt of a 'do' block: start - float
In the expression:
  do { headTS1;
   start - float;
   string
 \
 \xmax = ;
   end - float;
    }
In an equation for `header':
header
  = do { headTS1;
 start - float;
 string
   \
   \xmax = ;
  }

parsectest.hs:24:16:
Couldn't match expected type `Text.Parsec.Prim.ParsecT
String ()
Data.Functor.Identity.Identity Float'
with actual type `GenTokenParser s1 u1 m1
  - Text.Parsec.Prim.ParsecT s1 u1 m1
Double'
In a stmt of a 'do' block: end - float
In the expression:
  do { headTS1;
   start - float;
   string
 \
 \xmax = ;
   end - float;
    }
In an equation for `header':
header
  = do { headTS1;
 start - float;
 string
   \
   \xmax = ;
  }

parsectest.hs:26:9:
Couldn't match expected type `Text.Parsec.Prim.ParsecT
String ()
Data.Functor.Identity.Identity a0'
with actual type `GenTokenParser s2 u2 m2
  - Text.Parsec.Prim.ParsecT s2 u2 m2
Integer'
In a stmt of a 'do' block: integer
In the expression:
  do { headTS1;
   start - float;
   string
 \
 \xmax = ;
   end - float;
    }
In an equation for `header':
header
  = do { headTS1;
 start - float;
 string
   \
   \xmax = ;
  }
Failed, modules loaded: none.

I'm sure I'm doing something really stupid here, but I need help to get
through this problem. I've used the predefined letter parser at other
places in the code, so I can't understand why float and integer does
not work.

/Fredrik

-- 
Life is like a trumpet - if you don't put anything into it, you don't get
anything out of it.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Basic Parsec float integer parsing question

2013-07-05 Thread David McBride 
Token parsers are specific to different languages.  Afterall, haskell
parses floats differently than C, which is different from java
(probably).  In order to use it in your code you have to tell it that,
like so:

haskelldef = makeTokenParser haskellDef

header :: Parser LabelFile
header = do
  string headTS1
  start - fmap double2Float $ float haskelldef
  string \nxmax = 
  end - fmap double2Float $ float haskelldef
  string \ntiers? exists\nsize = 
  integer haskelldef
  char '\n'
  return $ LabelFile start end

You'll need to import GHC.Float (double2Float) to get those parsed
values as floats.

On Fri, Jul 5, 2013 at 12:42 PM, Fredrik Karlsson dargo...@gmail.com wrote:
 Dear list,

 Sorry for asking a simple parsec question, but both Parsec and Haskell is
 new to me, so please be gentle :-)

 I have this code:

 
 import Text.ParserCombinators.Parsec
 import Text.Parsec.Token
 import Text.ParserCombinators.Parsec.Char


 data VariableLine = VariableLine String String deriving Show
 data TierType = IntervalTier | PointTier deriving Show

 data Tier = Tier TierType String Float Float Integer
 data Label = Interval Float Float String
 data LabelFile = LabelFile Float Float

 symbol :: Parser Char
 symbol = oneOf !#$%|*+-/:=?@^_~

 testString = intervals [1]:\nxmin = 0 \nxmax = 0.028192
 \ntext = \\
 headTS1 = File type = \ooTextFile\\nObject class = \TextGrid\\n\nxmin
 =

 header :: Parser LabelFile
 header = do
 headTS1
 start - float
 string \nxmax = 
 end - float
 string \ntiers? exists\nsize = 
 integer
 char '\n'
 return $ LabelFile start end

 

 Loading it into ghci I get :

 Prelude :l parsectest.hs
 [1 of 1] Compiling Main ( parsectest.hs, interpreted )

 parsectest.hs:21:9:
 Couldn't match type `[]'
   with `Text.Parsec.Prim.ParsecT
   String () Data.Functor.Identity.Identity'
 Expected type: Text.Parsec.Prim.ParsecT
  String () Data.Functor.Identity.Identity Char
   Actual type: [Char]
 In a stmt of a 'do' block: headTS1
 In the expression:
   do { headTS1;
start - float;
string
  \
  \xmax = ;
end - float;
 }
 In an equation for `header':
 header
   = do { headTS1;
  start - float;
  string
\
\xmax = ;
   }

 parsectest.hs:22:18:
 Couldn't match expected type `Text.Parsec.Prim.ParsecT
 String () Data.Functor.Identity.Identity
 Float'
 with actual type `GenTokenParser s0 u0 m0
   - Text.Parsec.Prim.ParsecT s0 u0 m0
 Double'
 In a stmt of a 'do' block: start - float
 In the expression:
   do { headTS1;
start - float;
string
  \
  \xmax = ;
end - float;
 }
 In an equation for `header':
 header
   = do { headTS1;
  start - float;
  string
\
\xmax = ;
   }

 parsectest.hs:24:16:
 Couldn't match expected type `Text.Parsec.Prim.ParsecT
 String () Data.Functor.Identity.Identity
 Float'
 with actual type `GenTokenParser s1 u1 m1
   - Text.Parsec.Prim.ParsecT s1 u1 m1
 Double'
 In a stmt of a 'do' block: end - float
 In the expression:
   do { headTS1;
start - float;
string
  \
  \xmax = ;
end - float;
 }
 In an equation for `header':
 header
   = do { headTS1;
  start - float;
  string
\
\xmax = ;
   }

 parsectest.hs:26:9:
 Couldn't match expected type `Text.Parsec.Prim.ParsecT
 String () Data.Functor.Identity.Identity
 a0'
 with actual type `GenTokenParser s2 u2 m2
   - Text.Parsec.Prim.ParsecT s2 u2 m2
 Integer'
 In a stmt of a 'do' block: integer
 In the expression:
   do { headTS1;
start - float;
string
  \
  \xmax = ;
end - float;
 }
 In an equation for `header':
 header
   = do { headTS1;
  start - float;
  string
\
\xmax = ;
   }
 Failed, modules loaded: none.

 I'm sure I'm doing something really stupid here, but I need help to get
 through this problem.