option -package:Cabal

option x p will either parse p or return x without consuming any input.

option x p tries to apply parser p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

priority  = option 0 (do{ d <- digit
; return (digitToInt d)
})

Builder for an option using the given reader. This is a regular option, and should always have either a long or short name specified in the modifiers (or both).

nameParser = option str ( long "name" <> short 'n' )

option x p tries to apply action p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

priority  = option 0 (digitToInt <$> digit)

Combinator for the <option> element. Example:

option $ span $ toHtml "foo"

Result:

<option><span>foo</span></option>

option x p tries to apply parser p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

priority  = option 0 (do{ d <- digit
; return (digitToInt d)
})

option x p tries to apply the parser p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

option x p = p <|> pure x

See also: optional.

option x p tries to apply parser p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

priority = option 0 (digitToInt <$> digit)

Transform a parser to a succeed with an empty value instead of failing See also: optional

>>> match (option "1" <> "2") "12"
["12"]

>>> match (option "1" <> "2") "2"
["2"]

option x p will either parse p or return x without consuming any input.

option def p will try to parse p and, if it fails, simply return def without consuming any input.

option x p will either parse p or return x without consuming any input.

option x p will either parse p or return x without consuming any input.

Try to parse an argument. You'll also need to add a reader, at least one long or short, and a metavar. Multiple options are redundant.

option x p tries to apply parser p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

Apply a list of options to a plot resolving any pending options.

Parse something if you can, else return first value

option a p = p // unit a