| Copyright | (c) Gershom Bazerman 2010 |
|---|---|
| License | BSD 3 Clause |
| Maintainer | gershomb@gmail.com |
| Stability | experimental |
| Safe Haskell | None |
| Language | Haskell98 |
Language.Javascript.JMacro
Contents
Description
Simple DSL for lightweight (untyped) programmatic generation of Javascript.
A number of examples are available in the source of Language.Javascript.JMacro.Prelude.
Functions to generate generic RPC wrappers (using json serialization) are available in Language.Javascript.JMacro.Rpc.
usage:
renderJs [jmacro|fun id x -> x|]
The above produces the id function at the top level.
renderJs [jmacro|var id = \x -> x;|]
So does the above here. However, as id is brought into scope by the keyword var, you do not get a variable named id in the generated javascript, but a variable with an arbitrary unique identifier.
renderJs [jmacro|var !id = \x -> x;|]
The above, by using the bang special form in a var declaration, produces a variable that really is named id.
renderJs [jmacro|function id(x) {return x;}|]The above is also id.
renderJs [jmacro|function !id(x) {return x;}|]As is the above (with the correct name).
renderJs [jmacro|fun id x {return x;}|]As is the above.
renderJs [jmacroE|foo(x,y)|]
The above is an expression representing the application of foo to x and y.
renderJs [jmacroE|foo x y|]]
As is the above.
renderJs [jmacroE|foo (x,y)|]
While the above is an error. (i.e. standard javascript function application cannot seperate the leading parenthesis of the argument from the function being applied)
\x -> [jmacroE|foo `(x)`|]
The above is a haskell expression that provides a function that takes an x, and yields an expression representing the application of foo to the value of x as transformed to a Javascript expression.
[jmacroE|\x ->`(foo x)`|]
Meanwhile, the above lambda is in Javascript, and brings the variable into scope both in javascript and in the enclosed antiquotes. The expression is a Javascript function that takes an x, and yields an expression produced by the application of the Haskell function foo as applied to the identifier x (which is of type JExpr -- i.e. a Javascript expression).
Other than that, the language is essentially Javascript (1.5). Note however that one must use semicolons in a principled fashion -- i.e. to end statements consistently. Otherwise, the parser will mistake the whitespace for a whitespace application, and odd things will occur. A further gotcha exists in regex literals, whicch cannot begin with a space. x 5 4 parses as ((x 5) 4). However, x 5 4 will parse as x(5 , 4). Such are the perils of operators used as delimeters in the presence of whitespace application.
Additional features in jmacro (documented on the wiki) include an infix application operator, and an enhanced destructuring bind.
Additional datatypes can be marshalled to Javascript by proper instance declarations for the ToJExpr class.
An experimental typechecker is available in the Language.Javascript.JMacro.Typed module.
- jmacro :: QuasiQuoter
- jmacroE :: QuasiQuoter
- parseJM :: String -> Either ParseError JStat
- parseJME :: String -> Either ParseError JExpr
- data JStat
- = DeclStat Ident (Maybe JLocalType)
- | ReturnStat JExpr
- | IfStat JExpr JStat JStat
- | WhileStat Bool JExpr JStat
- | ForInStat Bool Ident JExpr JStat
- | SwitchStat JExpr [(JExpr, JStat)] JStat
- | TryStat JStat Ident JStat JStat
- | BlockStat [JStat]
- | ApplStat JExpr [JExpr]
- | PPostStat Bool String JExpr
- | AssignStat JExpr JExpr
- | UnsatBlock (IdentSupply JStat)
- | AntiStat String
- | ForeignStat Ident JLocalType
- | LabelStat JsLabel JStat
- | BreakStat (Maybe JsLabel)
- | ContinueStat (Maybe JsLabel)
- data JExpr
- data JVal
- newtype Ident = StrI String
- newtype IdentSupply a = IS {
- runIdentSupply :: State [Ident] a
- type JsLabel = String
- class JMacro a where
- data JMGadt a where
- class Compos t where
- composOp :: Compos t => (forall a. t a -> t a) -> t b -> t b
- composOpM :: (Compos t, Monad m) => (forall a. t a -> m (t a)) -> t b -> m (t b)
- composOpM_ :: (Compos t, Monad m) => (forall a. t a -> m ()) -> t b -> m ()
- composOpFold :: Compos t => b -> (b -> b -> b) -> (forall a. t a -> b) -> t c -> b
- withHygiene :: JMacro a => (a -> a) -> a -> a
- scopify :: JStat -> JStat
- renderJs :: (JsToDoc a, JMacro a) => a -> Doc
- renderPrefixJs :: (JsToDoc a, JMacro a) => String -> a -> Doc
- class JsToDoc a where
- class ToJExpr a where
- jsv :: String -> JExpr
- jLam :: ToSat a => a -> JExpr
- jVar :: ToSat a => a -> JStat
- jVarTy :: ToSat a => a -> Maybe JLocalType -> JStat
- jFor :: (ToJExpr a, ToStat b) => JStat -> a -> JStat -> b -> JStat
- jForIn :: ToSat a => JExpr -> (JExpr -> a) -> JStat
- jForEachIn :: ToSat a => JExpr -> (JExpr -> a) -> JStat
- jTryCatchFinally :: ToSat a => JStat -> a -> JStat -> JStat
- expr2stat :: JExpr -> JStat
- class ToStat a where
- nullStat :: JStat
- jhEmpty :: Map String JExpr
- jhSingle :: ToJExpr a => String -> a -> Map String JExpr
- jhAdd :: ToJExpr a => String -> a -> Map String JExpr -> Map String JExpr
- jhFromList :: [(String, JExpr)] -> JVal
- jsSaturate :: JMacro a => Maybe String -> a -> a
- jtFromList :: JType -> [(String, JType)] -> JType
- newtype SaneDouble = SaneDouble Double
- module Language.Javascript.JMacro.Prelude
- module Language.Javascript.JMacro.Types
Documentation
jmacro :: QuasiQuoter Source #
QuasiQuoter for a block of JMacro statements.
jmacroE :: QuasiQuoter Source #
QuasiQuoter for a JMacro expression.
ADT
Statements
Constructors
Expressions
Values
Identifiers
newtype IdentSupply a Source #
Constructors
| IS | |
Fields
| |
Instances
| Functor IdentSupply Source # | |
| Eq a => Eq (IdentSupply a) Source # | |
| Data a => Data (IdentSupply a) Source # | |
| Ord a => Ord (IdentSupply a) Source # | |
| Show a => Show (IdentSupply a) Source # | |
Generic traversal (via compos)
Compos and ops for generic traversal as defined over the JMacro ADT.
Utility class to coerce the ADT into a regular structure.
Union type to allow regular traversal by compos.
Minimal complete definition
composOpM_ :: (Compos t, Monad m) => (forall a. t a -> m ()) -> t b -> m () Source #
composOpFold :: Compos t => b -> (b -> b -> b) -> (forall a. t a -> b) -> t c -> b Source #
Hygienic transformation
withHygiene :: JMacro a => (a -> a) -> a -> a Source #
Apply a transformation to a fully saturated syntax tree, taking care to return any free variables back to their free state following the transformation. As the transformation preserves free variables, it is hygienic.
scopify :: JStat -> JStat Source #
Takes a fully saturated expression and transforms it to use unique variables that respect scope.
Display/Output
renderJs :: (JsToDoc a, JMacro a) => a -> Doc Source #
Render a syntax tree as a pretty-printable document (simply showing the resultant doc produces a nice, well formatted String).
renderPrefixJs :: (JsToDoc a, JMacro a) => String -> a -> Doc Source #
Render a syntax tree as a pretty-printable document, using a given prefix to all generated names. Use this with distinct prefixes to ensure distinct generated names between independent calls to render(Prefix)Js.
Ad-hoc data marshalling
class ToJExpr a where Source #
Things that can be marshalled into javascript values. Instantiate for any necessary data structures.
Minimal complete definition
Instances
| ToJExpr Bool Source # | |
| ToJExpr Char Source # | |
| ToJExpr Double Source # | |
| ToJExpr Int Source # | |
| ToJExpr Integer Source # | |
| ToJExpr () Source # | |
| ToJExpr Text Source # | |
| ToJExpr Value Source # | |
| ToJExpr Text Source # | |
| ToJExpr JVal Source # | |
| ToJExpr JExpr Source # | |
| ToJExpr a => ToJExpr [a] Source # | |
| (ToJExpr a, ToJExpr b) => ToJExpr (a, b) Source # | |
| ToJExpr a => ToJExpr (Map String a) Source # | |
| (ToJExpr a, ToJExpr b, ToJExpr c) => ToJExpr (a, b, c) Source # | |
| (ToJExpr a, ToJExpr b, ToJExpr c, ToJExpr d) => ToJExpr (a, b, c, d) Source # | |
| (ToJExpr a, ToJExpr b, ToJExpr c, ToJExpr d, ToJExpr e) => ToJExpr (a, b, c, d, e) Source # | |
| (ToJExpr a, ToJExpr b, ToJExpr c, ToJExpr d, ToJExpr e, ToJExpr f) => ToJExpr (a, b, c, d, e, f) Source # | |
Literals
Occasionally helpful combinators
jLam :: ToSat a => a -> JExpr Source #
Create a new anonymous function. The result is an expression.
Usage:
jLam $ x y -> {JExpr involving x and y}
jVar :: ToSat a => a -> JStat Source #
Introduce a new variable into scope for the duration
of the enclosed expression. The result is a block statement.
Usage:
jVar $ x y -> {JExpr involving x and y}
jVarTy :: ToSat a => a -> Maybe JLocalType -> JStat Source #
Introduce a new variable with optional type into scope for the duration
of the enclosed expression. The result is a block statement.
Usage:
jVar $ x y -> {JExpr involving x and y}
jForIn :: ToSat a => JExpr -> (JExpr -> a) -> JStat Source #
Create a for in statement.
Usage:
jForIn {expression} $ x -> {block involving x}
jForEachIn :: ToSat a => JExpr -> (JExpr -> a) -> JStat Source #
As with "jForIn" but creating a "for each in" statement.
Minimal complete definition
Hash combinators
Utility
jsSaturate :: JMacro a => Maybe String -> a -> a Source #
Given an optional prefix, fills in all free variable names with a supply of names generated by the prefix.