Language.Rust.Parser

Selecting the right parser may require adding an annotation or using -XTypeApplications to avoid an "Ambiguous type variable" error.

Using void (as in the examples below) exploits the fact that most AST nodes are instances of Functor to discard the Span annotation that is attached to most parsed AST nodes. Conversely, if you wish to extract the Span annotation, the Located typeclass provides a spanOf method.

The examples below assume the following GHCi flags and imports:

>>> :set -XTypeApplications -XOverloadedStrings
>>> import Language.Rust.Syntax.AST
>>> import Control.Monad ( void )
>>> import System.IO

Parsing

parse :: Parse a => InputStream -> Either ParseFail a

Parse something from an input stream (it is assumed the initial position is initPos).

>>> fmap void $ parse @(Expr Span) "x + 1"
Right (Binary [] AddOp (PathExpr [] Nothing (Path False [PathSegment "x" Nothing ()] ()) ())
                       (Lit [] (Int Dec 1 Unsuffixed ()) ())
                       ())

>>> fmap void $ parse @(Expr Span) "x + "
Left (parse failure at 1:4 (Syntax error: unexpected `<EOF>' (expected an expression)))

parse' :: Parse a => InputStream -> a

Same as parse, but throws a ParseFail exception if it cannot parse. This function is intended for situations in which you are already stuck catching exceptions - otherwise you should prefer parse.

>>> void $ parse' @(Expr Span) "x + 1"
Binary [] AddOp (PathExpr [] Nothing (Path False [PathSegment "x" Nothing ()] ()) ())
                (Lit [] (Int Dec 1 Unsuffixed ()) ())
                ()

>>> void $ parse' @(Expr Span) "x + "
*** Exception: parse failure at 1:4 (Syntax error: unexpected `<EOF>' (expected an expression))

readSourceFile :: Handle -> IO (SourceFile Span)

Given a handle to a Rust source file, read that file and parse it into a SourceFile

>>> writeFile "empty_main.rs" "fn main() { }"
>>> fmap void $ withFile "empty_main.rs" ReadMode readSourceFile
SourceFile Nothing [] [Fn [] InheritedV "main"
                          (FnDecl [] Nothing False ())
                          Normal NotConst Rust
                          (Generics [] [] (WhereClause [] ()) ())
                          (Block [] Normal ()) ()]

readTokens :: Handle -> IO [Spanned Token]

Given a path pointing to a Rust source file, read that file and lex it (ignoring whitespace)

>>> writeFile "empty_main.rs" "fn main() { }"
>>> withFile "empty_main.rs" ReadMode readTokens
[fn,main,(,),{,}]

class Parse a where

Describes things that can be parsed

Minimal complete definition

parser

Methods

parser :: P a

Complete parser (fails if not all of the input is consumed)

Instances

Parse TokenTree

Methods

parser :: P TokenTree

Parse TokenStream

Methods

parser :: P TokenStream

Parse (WhereClause Span)

Methods

parser :: P (WhereClause Span)

Parse (TyParam Span)

Methods

parser :: P (TyParam Span)

Parse (Ty Span)

Methods

parser :: P (Ty Span)

Parse (TraitItem Span)

Methods

parser :: P (TraitItem Span)

Parse (Stmt Span)

Methods

parser :: P (Stmt Span)

Parse (Pat Span)

Methods

parser :: P (Pat Span)

Parse (Lit Span)

Methods

parser :: P (Lit Span)

Parse (SourceFile Span)

Methods

parser :: P (SourceFile Span)

Parse (LifetimeDef Span)

Methods

parser :: P (LifetimeDef Span)

Parse (Item Span)

Methods

parser :: P (Item Span)

Parse (ImplItem Span)

Methods

parser :: P (ImplItem Span)

Parse (Generics Span)

Methods

parser :: P (Generics Span)

Parse (Expr Span)

Methods

parser :: P (Expr Span)

Parse (Block Span)

Methods

parser :: P (Block Span)

Parse (Attribute Span)

Methods

parser :: P (Attribute Span)

data P a

Parsing and lexing monad. A value of type P a represents a parser that can be run (using execParser) to possibly produce a value of type a.

Instances

Monad P

Methods

(>>=) :: P a -> (a -> P b) -> P b

(>>) :: P a -> P b -> P b

return :: a -> P a

fail :: String -> P a

Functor P

Methods

fmap :: (a -> b) -> P a -> P b

(<$) :: a -> P b -> P a

Applicative P

Methods

pure :: a -> P a

(<*>) :: P (a -> b) -> P a -> P b

liftA2 :: (a -> b -> c) -> P a -> P b -> P c

(*>) :: P a -> P b -> P b

(<*) :: P a -> P b -> P a

execParser :: P a -> InputStream -> Position -> Either ParseFail a

Execute the given parser on the supplied input stream at the given start position, returning either the position of an error and the error message, or the value parsed.

execParserTokens :: P a -> [Spanned Token] -> Position -> Either ParseFail a

Same as execParser, but working from a list of tokens instead of an InputStream.

initPos :: Position

Starting position in a file.

data Span

Spans represent a contiguous region of code, delimited by two Positions. The endpoints are inclusive. Analogous to the information encoded in a selection.

Instances

Eq Span

Methods

(==) :: Span -> Span -> Bool

(/=) :: Span -> Span -> Bool

Data Span

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Span -> c Span

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Span

toConstr :: Span -> Constr

dataTypeOf :: Span -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c Span)

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Span)

gmapT :: (forall b. Data b => b -> b) -> Span -> Span

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Span -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Span -> r

gmapQ :: (forall d. Data d => d -> u) -> Span -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Span -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Span -> m Span

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Span -> m Span

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Span -> m Span

Ord Span

Methods

compare :: Span -> Span -> Ordering

(<) :: Span -> Span -> Bool

(<=) :: Span -> Span -> Bool

(>) :: Span -> Span -> Bool

(>=) :: Span -> Span -> Bool

max :: Span -> Span -> Span

min :: Span -> Span -> Span

Show Span

Field names are not shown

Methods

showsPrec :: Int -> Span -> ShowS

show :: Span -> String

showList :: [Span] -> ShowS

Generic Span

Associated Types

type Rep Span :: * -> *

Methods

from :: Span -> Rep Span x

to :: Rep Span x -> Span

Semigroup Span

smallest covering Span

Methods

(<>) :: Span -> Span -> Span

sconcat :: NonEmpty Span -> Span

stimes :: Integral b => b -> Span -> Span

Monoid Span

Methods

mempty :: Span

mappend :: Span -> Span -> Span

mconcat :: [Span] -> Span

NFData Span

Methods

rnf :: Span -> ()

Located Span

Methods

spanOf :: Span -> Span

Pretty Span

Methods

prettyUnresolved :: Span -> Doc b

Parse (WhereClause Span)

Methods

parser :: P (WhereClause Span)

Parse (TyParam Span)

Methods

parser :: P (TyParam Span)

Parse (Ty Span)

Methods

parser :: P (Ty Span)

Parse (TraitItem Span)

Methods

parser :: P (TraitItem Span)

Parse (Stmt Span)

Methods

parser :: P (Stmt Span)

Parse (Pat Span)

Methods

parser :: P (Pat Span)

Parse (Lit Span)

Methods

parser :: P (Lit Span)

Parse (SourceFile Span)

Methods

parser :: P (SourceFile Span)

Parse (LifetimeDef Span)

Methods

parser :: P (LifetimeDef Span)

Parse (Item Span)

Methods

parser :: P (Item Span)

Parse (ImplItem Span)

Methods

parser :: P (ImplItem Span)

Parse (Generics Span)

Methods

parser :: P (Generics Span)

Parse (Expr Span)

Methods

parser :: P (Expr Span)

Parse (Block Span)

Methods

parser :: P (Block Span)

Parse (Attribute Span)

Methods

parser :: P (Attribute Span)

type Rep Span

type Rep Span = D1 * (MetaData "Span" "Language.Rust.Data.Position" "language-rust-0.2.0.27-AdTGPQ0ClkM3k0DGaVHmew" False) (C1 * (MetaCons "Span" PrefixI True) ((:*:) * (S1 * (MetaSel (Just Symbol "lo") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Position)) (S1 * (MetaSel (Just Symbol "hi") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Position))))

Lexing

lexToken :: P (Spanned Token)

Lexer for one Token. The only token this cannot produce is Interpolated.

lexNonSpace :: P (Spanned Token)

Lexer for one non-whitespace Token. The only tokens this cannot produce are Interpolated and Space (which includes comments that aren't doc comments).

lexTokens :: P (Spanned Token) -> P [Spanned Token]

Apply the given lexer repeatedly until (but not including) the Eof token. Meant for debugging purposes - in general this defeats the point of a threaded lexer.

translateLit :: LitTok -> Suffix -> a -> Lit a

Parse a valid LitTok into a Lit.

Input stream

readInputStream :: FilePath -> IO InputStream

Read an encoded file into an InputStream

hReadInputStream :: Handle -> IO InputStream

Read an InputStream from a Handle

inputStreamToString :: InputStream -> String

Convert InputStream to String.

inputStreamFromString :: String -> InputStream

Convert a String to an InputStream.

Error reporting

lexicalError :: P a

Signal a lexical error.

parseError :: Show b => b -> P a

Signal a syntax error.

data ParseFail

Exceptions that occur during parsing

Constructors

ParseFail Position String

Instances

Eq ParseFail

Methods

(==) :: ParseFail -> ParseFail -> Bool

(/=) :: ParseFail -> ParseFail -> Bool

Show ParseFail

Methods

showsPrec :: Int -> ParseFail -> ShowS

show :: ParseFail -> String

showList :: [ParseFail] -> ShowS

Exception ParseFail

Methods

toException :: ParseFail -> SomeException

fromException :: SomeException -> Maybe ParseFail

displayException :: ParseFail -> String