Re: CSV parser, quotes?
In attempting to improve the CSV parser based on comments, I have the following code that's attached. I'm having a heck of a time getting the double quotes = an escaped quote thing to work. There is some commented out code which was my last attempt. As it stands the code works, minus the escaped quotes. Remove the comments and it just hangs. I haven't looked at the code, but it occurs to me that the issue may be to do with lookahead. If you're in a quoted string, then means a quote character in the string, but , or \n or EOF mean end of cell. You can't tell which is which until you read the final character; specifically, you can't tell if the string has ended until you read the newline or EOF at the end of the line. Does that help? --KW 8-) ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
CSV parser, quotes?
In attempting to improve the CSV parser based on comments, I have the
following code that's attached. I'm having a heck of a time getting the
double quotes = an escaped quote thing to work. There is some commented out
code which was my last attempt. As it stands the code works, minus the
escaped quotes. Remove the comments and it just hangs.
module CSV (contents, csv) where
import Parsec
--
-- CSV Module
--
-- Useful common parsers
comma :: Parser Char
comma = char ','
quote :: Parser Char
quote = char '\'
-- How to handle these buggers
--esc_quote :: Parser Char
--esc_quote = do {char '\'; char '\';}
--text :: Parser String
--text = do {esc_quote; t-text; return ('\':t)}
-- | do {c - noneOf \; t-text; return (c:t) }
-- | return
-- A cell can be a quoted value, a number or empty
-- Quotes can be embedded by using double quotes
cell :: Parser String
cell = between quote quote (many (noneOf \)) -- quoted values
--cell = between quote quote text -- quoted values
| many1 (noneOf \,\n) -- unquoted values
| return -- give up, Empty cell
-- Group of cells with a newline
cells :: Parser [String]
cells = do c - sepBy cell comma
newline
return c
-- Comma Separated Values, set of rows followed by eof
csv :: Parser [[String]]
csv= manyTill cells eof
-- Useful For extracting comma delimited values of a cell
contents :: Parser [String]
contents = sepBy1 (many (noneOf ,)) comma
___
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Re: CSV parser, quotes?
The Parsec library code contains string-parsing (with escapes) that you
might be able to use or canibalize. See 'StringLiteral' et seq in
ParsecToken.hs. The escape handling there is a fair amount of code, bit it
covers a lot of escape options.
#g
--
At 14:54 30/07/03 -0500, Shawn P. Garbett wrote:
In attempting to improve the CSV parser based on comments, I have the
following code that's attached. I'm having a heck of a time getting the
double quotes = an escaped quote thing to work. There is some commented out
code which was my last attempt. As it stands the code works, minus the
escaped quotes. Remove the comments and it just hangs.
module CSV (contents, csv) where
import Parsec
--
-- CSV Module
--
-- Useful common parsers
comma :: Parser Char
comma = char ','
quote :: Parser Char
quote = char '\'
-- How to handle these buggers
--esc_quote :: Parser Char
--esc_quote = do {char '\'; char '\';}
--text :: Parser String
--text = do {esc_quote; t-text; return ('\':t)}
-- | do {c - noneOf \; t-text; return (c:t) }
-- | return
-- A cell can be a quoted value, a number or empty
-- Quotes can be embedded by using double quotes
cell :: Parser String
cell = between quote quote (many (noneOf \)) -- quoted values
--cell = between quote quote text -- quoted values
| many1 (noneOf \,\n) -- unquoted values
| return -- give up, Empty
cell
-- Group of cells with a newline
cells :: Parser [String]
cells = do c - sepBy cell comma
newline
return c
-- Comma Separated Values, set of rows followed by eof
csv :: Parser [[String]]
csv= manyTill cells eof
-- Useful For extracting comma delimited values of a cell
contents :: Parser [String]
contents = sepBy1 (many (noneOf ,)) comma
___
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---
Graham Klyne
[EMAIL PROTECTED]
PGP: 0FAA 69FF C083 000B A2E9 A131 01B9 1C7A DBCA CB5E
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