CustomInterpolation.Config

Documentation

>>> import CustomInterpolation -- doctest setup, ignore this

data InterpolationConfig a

Rules for interpolating a string.

Constructors

InterpolationConfig

Fields

• handlers :: [Interpolator a]

  The Interpolators that handle interpolated expressions.

• finalize :: ([a], Q Exp) -> Q Exp

  Used for complex Interpolators that return additional values. Reduces these accumulated values to a single Q Exp.

• escape :: Char -> Char

  Handle backslash-escaped characters (can be used to add special characters like n).

Instances

Default (InterpolationConfig a)

def = defaultConfig

Defined in CustomInterpolation.Config

Methods

def :: InterpolationConfig a

simpleConfig :: InterpolationConfig ()

Type-restricted simple version of defaultConfig. Use this if you just want to substitute interpolated segments with a string expression.

defaultConfig :: InterpolationConfig a

Default InterpolationConfig. Has no handlers, finalize ignores any extra values returned when interpolating and escape does nothing.

data Interpolator a

Constructors

Interpolator

Fields

• prefix :: Prefix

  InterpolationConfig prefix, a prefix of e.g. "$" will lead to anything inside ${expr} being interpolated (assuming curlyBrackets).

• handler :: Q Exp -> (a, Q Exp)

  Transforms the interpolated string segment into a string expression and some value of type a to accumulate.

• brackets :: Brackets

  The brackets to use for the interpolation syntax.

type Prefix = String

data Brackets

Constructors

Brackets

Fields

• opening :: Char
• closing :: Char

Instances

Show Brackets

Defined in CustomInterpolation.Config

Methods

showsPrec :: Int -> Brackets -> ShowS

show :: Brackets -> String

showList :: [Brackets] -> ShowS

curlyBrackets :: Brackets

{}

roundBrackets :: Brackets

()

squareBrackets :: Brackets

[]

angleBrackets :: Brackets

<>

simpleInterpolator :: Interpolator ()

Default Interpolator. Inserts the interpolated expression as is and uses curlyBrackets with no prefix.

applyInterpolator :: Monoid a => Q Exp -> Interpolator a

Create an Interpolator that applies a quoted function to the interpolated expression. Uses curlyBrackets and no prefix.

Example

>>> $(interpolate (simpleConfig {handlers = [applyInterpolator [|show . (^ 2)|]]}) "two squared equals {2}")
"two squared equals 4"