Equivalent to decodeWith defaultDecodeOptions.

Create a Producer that takes a ByteString Producer as input, producing either errors or FromRecords.

Equivalent to decodeByNameWith defaultDecodeOptions.

Create a Producer that takes a ByteString Producer as input, producing either errors or FromNamedRecords.

Create a Record Producer by feeding ByteStrings into a Parser

Create a NamedRecord Producer by feeding ByteStrings into a Parser

Encode records as strict ByteStrings

Encode records as strict ByteStrings

Encode named records as strict ByteStrings

Encode named records as strict ByteStrings

Encoding options for CSV files.

Options that controls how data is encoded. These options can be used to e.g. encode data in a tab-separated format instead of in a comma-separated format.

To avoid having your program stop compiling when new fields are added to EncodeOptions, create option records by overriding values in defaultEncodeOptions. Example:

myOptions = defaultEncodeOptions {
      encDelimiter = fromIntegral (ord '\t')
    }

N.B. The encDelimiter must not be the quote character (i.e. ") or one of the record separator characters (i.e. \n or \r).

Alias for namedField.

Alias for lookup.

Alias for index.

A type that can be converted from a single CSV record, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Record has the wrong number of columns.

Given this example data:

John,56
Jane,55

here's an example type and instance:

data Person = Person { name :: !Text, age :: !Int }

instance FromRecord Person where
    parseRecord v
        | length v == 2 = Person <$>
                          v .! 0 <*>
                          v .! 1
        | otherwise     = mzero

A type that can be converted to a single CSV record.

An example type and instance:

data Person = Person { name :: !Text, age :: !Int }

instance ToRecord Person where
    toRecord (Person name age) = record [
        toField name, toField age]

Outputs data on this form:

John,56
Jane,55

A type that can be converted from a single CSV record, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Record has the wrong number of columns.

Given this example data:

name,age
John,56
Jane,55

here's an example type and instance:

{-# LANGUAGE OverloadedStrings #-}

data Person = Person { name :: !Text, age :: !Int }

instance FromNamedRecord Person where
    parseNamedRecord m = Person <$>
                         m .: "name" <*>
                         m .: "age"

Note the use of the OverloadedStrings language extension which enables ByteString values to be written as string literals.

A type that can be converted to a single CSV record.

An example type and instance:

data Person = Person { name :: !Text, age :: !Int }

instance ToNamedRecord Person where
    toNamedRecord (Person name age) = namedRecord [
        "name" .= name, "age" .= age]

A type that can be converted from a single CSV field, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Field can't be converted to the given type.

Example type and instance:

{-# LANGUAGE OverloadedStrings #-}

data Color = Red | Green | Blue

instance FromField Color where
    parseField s
        | s == "R"  = pure Red
        | s == "G"  = pure Green
        | s == "B"  = pure Blue
        | otherwise = mzero

A type that can be converted to a single CSV field.

Example type and instance:

{-# LANGUAGE OverloadedStrings #-}

data Color = Red | Green | Blue

instance ToField Color where
    toField Red   = "R"
    toField Green = "G"
    toField Blue  = "B"

Decoding options for parsing CSV files.

Options that controls how data is decoded. These options can be used to e.g. decode tab-separated data instead of comma-separated data.

To avoid having your program stop compiling when new fields are added to DecodeOptions, create option records by overriding values in defaultDecodeOptions. Example:

myOptions = defaultDecodeOptions {
      decDelimiter = fromIntegral (ord '\t')
    }

A record corresponds to a single line in a CSV file.

The header corresponds to the first line a CSV file. Not all CSV files have a header.

A record corresponds to a single line in a CSV file, indexed by the column name rather than the column index.

A single field within a record.

Is the CSV data preceded by a header?