Parse a Text value as an INI file and run an IniParser over it

An IniParser value represents a computation for parsing entire INI-format files.

A SectionParser value represents a computation for parsing a single section of an INI-format file.

Find a named section in the INI file and parse it with the provided section parser, failing if the section does not exist. In order to support classic INI files with capitalized section names, section lookup is case-insensitive.

>>> parseIniFile "[ONE]\nx = hello\n" $ section "ONE" (field "x")
Right "hello"
>>> parseIniFile "[ONE]\nx = hello\n" $ section "TWO" (field "x")
Left "No top-level section named \"TWO\""

Find a named section in the INI file and parse it with the provided section parser, returning Nothing if the section does not exist. In order to support classic INI files with capitalized section names, section lookup is case-insensitive.

>>> parseIniFile "[ONE]\nx = hello\n" $ sectionMb "ONE" (field "x")
Right (Just "hello")
>>> parseIniFile "[ONE]\nx = hello\n" $ sectionMb "TWO" (field "x")
Right Nothing

Find a named section in the INI file and parse it with the provided section parser, returning a default value if the section does not exist. In order to support classic INI files with capitalized section names, section lookup is case-insensitive.

>>> parseIniFile "[ONE]\nx = hello\n" $ sectionDef "ONE" "def" (field "x")
Right "hello"
>>> parseIniFile "[ONE]\nx = hello\n" $ sectionDef "TWO" "def" (field "x")
Right "def"

Retrieve a field, failing if it doesn't exist, and return its raw value.

>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (field "x")
Right "hello"
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (field "y")
Left "Missing field \"y\" in section \"MAIN\""

Retrieve a field and use the supplied parser to parse it as a value, failing if the field does not exist, or if the parser fails to produce a value.

>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldOf "x" number)
Right 72
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldOf "x" number)
Left "Line 2, in section \"MAIN\": Unable to parse \"hello\" as a value of type Integer"
>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldOf "y" number)
Left "Missing field \"y\" in section \"MAIN\""

Retrieve a field, returning a Nothing value if it does not exist.

>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldMb "x")
Right (Just "hello")
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldMb "y")
Right Nothing

Retrieve a field and parse it according to the given parser, returning Nothing if it does not exist. If the parser fails, then this will fail.

>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldMbOf "x" number)
Right (Just 72)
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldMbOf "x" number)
Left "Line 2, in section \"MAIN\": Unable to parse \"hello\" as a value of type Integer"
>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldMbOf "y" number)
Right Nothing

Retrieve a field and supply a default value for if it doesn't exist.

>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldDef "x" "def")
Right "hello"
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldDef "y" "def")
Right "def"

Retrieve a field, parsing it according to the given parser, and returning a default value if it does not exist. If the parser fails, then this will fail.

>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldDefOf "x" number 99)
Right 72
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldDefOf "x" number 99)
Left "Line 2, in section \"MAIN\": Unable to parse \"hello\" as a value of type Integer"
>>> parseIniFile "[MAIN]\nx = 72\n" $ section "MAIN" (fieldDefOf "y" number 99)
Right 99

Retrieve a field and treat it as a boolean, failing if it does not exist.

>>> parseIniFile "[MAIN]\nx = yes\n" $ section "MAIN" (fieldFlag "x")
Right True
>>> parseIniFile "[MAIN]\nx = yes\n" $ section "MAIN" (fieldFlag "y")
Left "Missing field \"y\" in section \"MAIN\""

Retrieve a field and treat it as a boolean, subsituting a default value if it doesn't exist.

>>> parseIniFile "[MAIN]\nx = yes\n" $ section "MAIN" (fieldFlagDef "x" False)
Right True
>>> parseIniFile "[MAIN]\nx = hello\n" $ section "MAIN" (fieldFlagDef "x" False)
Left "Line 2, in section \"MAIN\": Unable to parse \"hello\" as a boolean"
>>> parseIniFile "[MAIN]\nx = yes\n" $ section "MAIN" (fieldFlagDef "y" False)
Right False

Try to use the Read instance for a type to parse a value, failing with a human-readable error message if reading fails.

>>> readable "(5, 7)" :: Either String (Int, Int)
Right (5,7)
>>> readable "hello" :: Either String (Int, Int)
Left "Unable to parse \"hello\" as a value of type (Int,Int)"

Try to use the Read instance for a numeric type to parse a value, failing with a human-readable error message if reading fails.

>>> number "5" :: Either String Int
Right 5
>>> number "hello" :: Either String Int
Left "Unable to parse \"hello\" as a value of type Int"

Convert a textual value to the appropriate string type. This will never fail.

>>> string "foo" :: Either String String
Right "foo"

Convert a string that represents a boolean to a proper boolean. This is case-insensitive, and matches the words true, false, yes, no, as well as single-letter abbreviations for all of the above. If the input does not match, then this will fail with a human-readable error message.

>>> flag "TRUE"
Right True
>>> flag "y"
Right True
>>> flag "no"
Right False
>>> flag "F"
Right False
>>> flag "That's a secret!"
Left "Unable to parse \"That's a secret!\" as a boolean"

Convert a reader for a value into a reader for a list of those values, separated by a chosen separator. This will split apart the string on that separator, get rid of leading and trailing whitespace on the individual chunks, and then attempt to parse each of them according to the function provided, turning the result into a list.

This is overloaded with the IsList typeclass, so it can be used transparently to parse other list-like types.

>>> listWithSeparator "," number "2, 3, 4" :: Either String [Int]
Right [2,3,4]
>>> listWithSeparator " " number "7 8 9" :: Either String [Int]
Right [7,8,9]
>>> listWithSeparator ":" string "/bin:/usr/bin" :: Either String [FilePath]
Right ["/bin","/usr/bin"]
>>> listWithSeparator "," number "7 8 9" :: Either String [Int]
Left "Unable to parse \"2 3 4\" as a value of type Int"