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126 lines
4.1 KiB
Haskell
126 lines
4.1 KiB
Haskell
-----------------------------------------------------------------------------
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-- |
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-- Module : Text.Parsec.Pos
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-- Copyright : (c) Daan Leijen 1999-2001, (c) Paolo Martini 2007
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-- License : BSD-style (see the LICENSE file)
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--
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-- Maintainer : derek.a.elkins@gmail.com
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-- Stability : provisional
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-- Portability : portable
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--
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-- Textual source positions.
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--
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-----------------------------------------------------------------------------
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module Text.Parsec.Pos
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( SourceName, Line, Column
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, SourcePos
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, sourceLine, sourceColumn, sourceName
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, incSourceLine, incSourceColumn
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, setSourceLine, setSourceColumn, setSourceName
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, newPos, initialPos
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, updatePosChar, updatePosString
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) where
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import Data.Generics
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-- < Source positions: a file name, a line and a column
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-- upper left is (1,1)
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type SourceName = String
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type Line = Int
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type Column = Int
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-- | The abstract data type @SourcePos@ represents source positions. It
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-- contains the name of the source (i.e. file name), a line number and
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-- a column number. @SourcePos@ is an instance of the 'Show', 'Eq' and
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-- 'Ord' class.
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data SourcePos = SourcePos SourceName !Line !Column
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deriving ( Eq, Ord, Data, Typeable)
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-- | Create a new 'SourcePos' with the given source name,
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-- line number and column number.
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newPos :: SourceName -> Line -> Column -> SourcePos
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newPos name line column
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= SourcePos name line column
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-- | Create a new 'SourcePos' with the given source name,
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-- and line number and column number set to 1, the upper left.
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initialPos :: SourceName -> SourcePos
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initialPos name
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= newPos name 1 1
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-- | Extracts the name of the source from a source position.
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sourceName :: SourcePos -> SourceName
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sourceName (SourcePos name _line _column) = name
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-- | Extracts the line number from a source position.
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sourceLine :: SourcePos -> Line
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sourceLine (SourcePos _name line _column) = line
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-- | Extracts the column number from a source position.
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sourceColumn :: SourcePos -> Column
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sourceColumn (SourcePos _name _line column) = column
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-- | Increments the line number of a source position.
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incSourceLine :: SourcePos -> Line -> SourcePos
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incSourceLine (SourcePos name line column) n = SourcePos name (line+n) column
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-- | Increments the column number of a source position.
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incSourceColumn :: SourcePos -> Column -> SourcePos
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incSourceColumn (SourcePos name line column) n = SourcePos name line (column+n)
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-- | Set the name of the source.
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setSourceName :: SourcePos -> SourceName -> SourcePos
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setSourceName (SourcePos _name line column) n = SourcePos n line column
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-- | Set the line number of a source position.
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setSourceLine :: SourcePos -> Line -> SourcePos
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setSourceLine (SourcePos name _line column) n = SourcePos name n column
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-- | Set the column number of a source position.
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setSourceColumn :: SourcePos -> Column -> SourcePos
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setSourceColumn (SourcePos name line _column) n = SourcePos name line n
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-- | The expression @updatePosString pos s@ updates the source position
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-- @pos@ by calling 'updatePosChar' on every character in @s@, ie.
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-- @foldl updatePosChar pos string@.
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updatePosString :: SourcePos -> String -> SourcePos
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updatePosString pos string
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= foldl updatePosChar pos string
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-- | Update a source position given a character. If the character is a
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-- newline (\'\\n\') or carriage return (\'\\r\') the line number is
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-- incremented by 1. If the character is a tab (\'\t\') the column
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-- number is incremented to the nearest 8'th column, ie. @column + 8 -
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-- ((column-1) \`mod\` 8)@. In all other cases, the column is
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-- incremented by 1.
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updatePosChar :: SourcePos -> Char -> SourcePos
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updatePosChar (SourcePos name line column) c
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= case c of
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'\n' -> SourcePos name (line+1) 1
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'\t' -> SourcePos name line (column + 8 - ((column-1) `mod` 8))
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_ -> SourcePos name line (column + 1)
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instance Show SourcePos where
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show (SourcePos name line column)
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| null name = showLineColumn
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| otherwise = "\"" ++ name ++ "\" " ++ showLineColumn
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where
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showLineColumn = "(line " ++ show line ++
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", column " ++ show column ++
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")"
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