| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Agda.Syntax.Parser.LexActions
Description
This module contains the building blocks used to construct the lexer.
Synopsis
- lexToken :: Parser Token
- token :: (String -> Parser tok) -> LexAction tok
- withInterval :: ((Interval, String) -> tok) -> LexAction tok
- withInterval' :: (String -> a) -> ((Interval, a) -> tok) -> LexAction tok
- withInterval_ :: (Interval -> r) -> LexAction r
- withLayout :: Keyword -> LexAction r -> LexAction r
- andThen :: Parser () -> LexAction r -> LexAction r
- skip :: LexAction Token
- begin :: LexState -> LexAction Token
- end :: LexAction Token
- beginWith :: LexState -> LexAction a -> LexAction a
- endWith :: LexAction a -> LexAction a
- begin_ :: LexState -> LexAction Token
- end_ :: LexAction Token
- lexError :: String -> Parser a
- keyword :: Keyword -> LexAction Token
- symbol :: Symbol -> LexAction Token
- identifier :: LexAction Token
- literal :: Read a => (a -> Literal) -> LexAction Token
- literal' :: (String -> a) -> (a -> Literal) -> LexAction Token
- integer :: String -> Integer
- followedBy :: Char -> LexPredicate
- eof :: LexPredicate
- inState :: LexState -> LexPredicate
Main function
lexToken :: Parser Token Source #
Scan the input to find the next token. Calls
alexScanUser. This is the main lexing function
where all the work happens. The function lexer,
used by the parser is the continuation version of this function.
Lex actions
General actions
withInterval :: ((Interval, String) -> tok) -> LexAction tok Source #
Parse a token from an Interval and the lexed string.
withInterval' :: (String -> a) -> ((Interval, a) -> tok) -> LexAction tok Source #
Like withInterval, but applies a function to the string.
withInterval_ :: (Interval -> r) -> LexAction r Source #
Return a token without looking at the lexed string.
withLayout :: Keyword -> LexAction r -> LexAction r Source #
Executed for layout keywords. Enters the layout
state and performs the given action.
andThen :: Parser () -> LexAction r -> LexAction r infixr 1 Source #
Prepend some parser manipulation to an action.
beginWith :: LexState -> LexAction a -> LexAction a Source #
Enter a new state and perform the given action.
lexError :: String -> Parser a Source #
For lexical errors we want to report the current position as the site of
the error, whereas for parse errors the previous position is the one
we're interested in (since this will be the position of the token we just
lexed). This function does parseErrorAt the current position.
Specialized actions
keyword :: Keyword -> LexAction Token Source #
Parse a Keyword token, triggers layout for layoutKeywords.
identifier :: LexAction Token Source #
Parse an identifier. Identifiers can be qualified (see Name).
Example: Foo.Bar.f
Lex predicates
followedBy :: Char -> LexPredicate Source #
True when the given character is the next character of the input string.
eof :: LexPredicate Source #
True if we are at the end of the file.
inState :: LexState -> LexPredicate Source #
True if the given state appears somewhere on the state stack