B9.Content.AST

B9 produces not only VM-Images but also text documents such as configuration files required by virtual machines. This module is about creating and merging files containing parsable syntactic structures, such as most configuration files do.

Imagine you would want to create a cloud-init 'user-data' file from a set of 'user-data' snippets which each are valid 'user-data' files in yaml syntax and e.g. a writefiles section. Now the goal is, for b9 to be able to merge these snippets into one, such that all writefiles sections are combined into a single writefile section. Another example is OTP/Erlang sys.config files. This type class is the greatest commonon denominator of types describing a syntax that can be parsed, concatenated e.g. like in the above example and rendered. The actual concatenation operation is the append from Monoid, i.e. like monoid but without the need for an empty element.

Documentation

class Semigroup a => ConcatableSyntax a where

Methods

decodeSyntax :: FilePath -> ByteString -> Either String a

encodeSyntax :: a -> ByteString

Instances

ConcatableSyntax ByteString

ConcatableSyntax ErlangPropList

ConcatableSyntax YamlObject

class ConcatableSyntax a => ASTish a where

Structure data into an abstract syntax tree

Methods

fromAST :: (CanRender c, Applicative m, Monad m, MonadIO m, MonadReader Environment m) => AST c a -> m a

Instances

ASTish ErlangPropList

ASTish YamlObject

data AST c a

A simple AST wrapper for merging embeded ASTs

Constructors

ASTObj [(String, AST c a)]

ASTArr [AST c a]

ASTMerge [AST c a]

ASTEmbed c

ASTString String

ASTParse SourceFile

AST a

Instances

(Eq c, Eq a) => Eq (AST c a)

(Data c, Data a) => Data (AST c a)

(Read c, Read a) => Read (AST c a)

(Show c, Show a) => Show (AST c a)

(Arbitrary c, Arbitrary a) => Arbitrary (AST c a)

Typeable (* -> * -> *) AST

class CanRender c where

Things that produce byte strings.

Methods

render :: (Functor m, Applicative m, MonadIO m, MonadReader Environment m) => c -> m ByteString

Instances

CanRender Content