| License | BSD3 |
|---|---|
| Maintainer | cabal-devel@haskell.org |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Distribution.Parsec.Parser
Contents
Description
Synopsis
- data Field ann
- data Name ann = Name !ann !FieldName
- data FieldLine ann = FieldLine !ann !ByteString
- data SectionArg ann
- = SecArgName !ann !ByteString
- | SecArgStr !ann !ByteString
- | SecArgOther !ann !ByteString
- readFields :: ByteString -> Either ParseError [Field Position]
- readFields' :: ByteString -> Either ParseError ([Field Position], [LexWarning])
Types
A Cabal-like file consists of a series of fields (foo: bar) and sections (library ...).
A field name.
Invariant: ByteString is lower-case ASCII.
A line of text representing the value of a field from a Cabal file. A field may contain multiple lines.
Invariant: ByteString has no newlines.
Constructors
| FieldLine !ann !ByteString |
data SectionArg ann #
Section arguments, e.g. name of the library
Constructors
| SecArgName !ann !ByteString | identifier, or omething which loos like number. Also many dot numbers, i.e. "7.6.3" |
| SecArgStr !ann !ByteString | quoted string |
| SecArgOther !ann !ByteString | everything else, mm. operators (e.g. in if-section conditionals) |
Instances
| Functor SectionArg # | |
Defined in Distribution.Parsec.Field Methods fmap :: (a -> b) -> SectionArg a -> SectionArg b Source # (<$) :: a -> SectionArg b -> SectionArg a Source # | |
| Eq ann => Eq (SectionArg ann) # | |
Defined in Distribution.Parsec.Field Methods (==) :: SectionArg ann -> SectionArg ann -> Bool # (/=) :: SectionArg ann -> SectionArg ann -> Bool # | |
| Show ann => Show (SectionArg ann) # | |
Defined in Distribution.Parsec.Field | |
Grammar and parsing
CabalStyleFile ::= SecElems SecElems ::= SecElem* '\n'? SecElem ::= '\n' SecElemLayout | SecElemBraces SecElemLayout ::= FieldLayout | FieldBraces | SectionLayout | SectionBraces SecElemBraces ::= FieldInline | FieldBraces | SectionBraces FieldLayout ::= name:line? ('\n' line)* FieldBraces ::= name:'\n'? '{' content '}' FieldInline ::= name:content SectionLayout ::= name arg* SecElems SectionBraces ::= name arg* '\n'? '{' SecElems '}'
and the same thing but left factored...
SecElems ::= SecElem*
SecElem ::= '\n' name SecElemLayout
| name SecElemBraces
SecElemLayout ::= : FieldLayoutOrBraces
| arg* SectionLayoutOrBraces
FieldLayoutOrBraces ::= '\n'? '{' content '}'
| line? ('\n' line)*
SectionLayoutOrBraces ::= '\n'? '{' SecElems '\n'? '}'
| SecElems
SecElemBraces ::= : FieldInlineOrBraces
| arg* '\n'? '{' SecElems '\n'? '}'
FieldInlineOrBraces ::= '\n'? '{' content '}'
| content
Note how we have several productions with the sequence:
'\n'? '{'That is, an optional newline (and indent) followed by a { token.
In the SectionLayoutOrBraces case you can see that this makes it
not fully left factored (because SecElems can start with a n).
Fully left factoring here would be ugly, and though we could use a
lookahead of two tokens to resolve the alternatives, we can't
conveniently use Parsec's try here to get a lookahead of only two.
So instead we deal with this case in the lexer by making a line
where the first non-space is { lex as just the { token, without
the usual indent token. Then in the parser we can resolve everything
with just one token of lookahead and so without using try.
readFields :: ByteString -> Either ParseError [Field Position] #
Parse cabal style ByteString into list of Fields, i.e. the cabal AST.
readFields' :: ByteString -> Either ParseError ([Field Position], [LexWarning]) #
Like readFields but also return lexer warnings