Text.Ginger.GVal

GVal is a generic unitype value, representing the kind of values that Ginger can understand.

Most of the types in this module are parametrized over an m type, which is the host monad for template execution, as passed to runGingerT.

Documentation

type Function m = [(Maybe Text, GVal m)] -> m (GVal m)

A function that can be called from within a template execution context.

matchFuncArgs :: [Text] -> [(Maybe Text, GVal m)] -> (HashMap Text (GVal m), [GVal m], HashMap Text (GVal m))

Match arguments passed to a function at runtime against a list of declared argument names. matchFuncArgs argNames argsPassed returns (matchedArgs, positionalArgs, namedArgs), where matchedArgs is a list of arguments matched against declared names (by name or by position), positionalArgs are the unused positional (unnamed) arguments, and namedArgs are the unused named arguments.

data GVal m

Ginger value.

Constructors

GVal

Fields

asList :: Maybe [GVal m]

asDictItems :: Maybe [(Text, GVal m)]

asLookup :: Maybe (Text -> Maybe (GVal m))

asHtml :: Html

asText :: Text

asBoolean :: Bool

asNumber :: Maybe Scientific

asFunction :: Maybe (Function m)

length :: Maybe Int

isNull :: Bool

Instances

ToGVal m (GVal m)

Trivial instance for GVal itself

Show (GVal m)

For convenience, Show is implemented in a way that looks similar to JavaScript / JSON

IsString (GVal m)

Default (GVal m)

The default GVal is equivalent to NULL.

ToHtml (GVal m)

Converting to HTML hooks into the ToHtml instance for Text for most tags. Tags that have no obvious textual representation render as empty HTML.

isList :: GVal m -> Bool

isDict :: GVal m -> Bool

class ToGVal m a where

Types that implement conversion to GVal

Methods

toGVal :: a -> GVal m

Instances

ToGVal m Value

Convert Aeson Values to GVals over an arbitrary host monad. Because JSON cannot represent functions, this conversion will never produce a Function.

ToGVal m Html

ToGVal m Text

ToGVal m Text

ToGVal m Bool

ToGVal m Scientific

ToGVal m Integer

ToGVal m Int

ToGVal m v => ToGVal m [v]

ToGVal m v => ToGVal m (Maybe v)

ToGVal m (GVal m)

Trivial instance for GVal itself

ToGVal m v => ToGVal m (HashMap Text v)

lookupIndex :: Int -> GVal m -> Maybe (GVal m)

Treat a GVal as a flat list and look up a value by integer index. If the value is not a List, or if the index exceeds the list length, return Nothing.

lookupIndexMay :: Maybe Int -> GVal m -> Maybe (GVal m)

Helper function; look up a value by an integer index when the index may or may not be available. If no index is given, return Nothing.

lookupKey :: Text -> GVal m -> Maybe (GVal m)

lookupLoose :: GVal m -> GVal m -> Maybe (GVal m)

Loosely-typed lookup: try dictionary-style lookup first (treat index as a string, and container as a dictionary), if that doesn't yield anything (either because the index is not string-ish, or because the container doesn't provide dictionary-style access), try index-based lookup.

keys :: GVal m -> Maybe [Text]

Treat a GVal as a dictionary and list all the keys, with no particular ordering.

toNumber :: GVal m -> Maybe Scientific

Convert a GVal to a number.

toInt :: GVal m -> Maybe Int

Convert a GVal to an Int. The conversion will fail when the value is not numeric, and also if it is too large to fit in an Int.

toBoolean :: GVal m -> Bool

Loose cast to boolean.

Numeric zero, empty strings, empty lists, empty objects, Null, and boolean False are considered falsy, anything else (including functions) is considered true-ish.

toFunction :: GVal m -> Maybe (Function m)

Dynamically cast to a function. This yields Just a Function if the value is a function, Nothing if it's not.

fromFunction :: Function m -> GVal m

Turn a Function into a GVal

scientificToText :: Scientific -> Text