diff options
Diffstat (limited to 'src/Codec/Pesto/Parse.lhs')
| -rw-r--r-- | src/Codec/Pesto/Parse.lhs | 71 |
1 files changed, 33 insertions, 38 deletions
diff --git a/src/Codec/Pesto/Parse.lhs b/src/Codec/Pesto/Parse.lhs index 745d339..7deb511 100644 --- a/src/Codec/Pesto/Parse.lhs +++ b/src/Codec/Pesto/Parse.lhs @@ -12,12 +12,13 @@ Language syntax > , Object(..) > , Approximately(..) > , Amount(..) -> , Recipe(..) > , isResult > , isReference > , isAlternative > , isAnnotation > , isAction +> , isDirective +> , isUnknown > , spaces1 > , notspace > ) where @@ -33,50 +34,21 @@ Language syntax > > import Codec.Pesto.Serialize (serialize) -XXX: magic should be an operation -XXX: this parser should accept invalid operations +Pesto parses UTF-8_ encoded input files into a sequence of operations. -From the XXXsyntactic point of view a Pesto recipe is just a list of -space-delimited operations. It is encoded with UTF-8_ and starts with a magic -identifier (``%pesto-1``) followed by one or more spaces (spaces1_). Every +- stream of operations +- utf8 encoded +Every character within the Unicode whitespace class is considered a space. .. _UTF-8: https://tools.ietf.org/html/rfc3629 - .. _spaces1: -.. _Recipe: -> data Recipe = Recipe { -> version :: Integer -> , operations :: [(SourcePos, Operation)] -> } deriving Show -> -> recipe = Recipe -> <$> magic <* spaces1 -> <*> ((,) <$> getPosition <*> operation) `sepEndBy` spaces1 -> <* eof -> <?> "recipe" -> +> stream = ((,) <$> getPosition <*> operation) `sepEndBy` spaces1 +> <?> "stream" > spaces1 = many1 space -The file identifier consists of the string ``%pesto-`` followed by an integral -number and arbitrary non-space characters. They are reserved for future use and -must be ignored by parsers implementing this version of pesto. A byte order -mark (BOM) must not be used. - -> magic = string "%pesto-" *> int <* skipMany notspace <?> "magic" -> notspace = satisfy (not . isSpace) - -.. _Operation: -.. _Ingredient: -.. _Tool: -.. _Result: -.. _Alternative: -.. _Reference: -.. _Annotation: -.. _Action: - -The following *operations* are supported: +The following operations are supported: > data Operation = > Annotation String @@ -86,6 +58,8 @@ The following *operations* are supported: > | Reference Quantity > | Result Object > | Alternative Object +> | Directive String +> | Unknown String > deriving (Show, Eq) > > operation = @@ -96,6 +70,8 @@ The following *operations* are supported: > <|> try result > <|> try alternative > <|> try reference +> <|> try directive +> <|> try unknown > <?> "operation" The pesto grammar has two kinds of operations: The first one begins with a @@ -129,6 +105,19 @@ whitespace characters and then consumes an object or a quantity. > alternative = oparg '|' (Alternative <$> object) > reference = oparg '*' (Reference <$> quantity) +Additionally there are two special operations. Directives are similar to the +previous operations, but consume a qstr. + +> directive = oparg '%' (Directive <$> qstr) + +Unknown operations are the fallthrough-case and accept anything. They must not +be discarded at this point. The point of accepting anything is to fail as late +as possible while processing Pesto documents. This gives us a chance to print +helpful mesages that provide additional aid to the user who can then fix the +problem. + +> unknown = Unknown <$> many1 notspace + > testOparg = [ > cmpOperation "+100 g flour" (Right (Ingredient (Quantity (Exact (AmountRatio (100%1))) "g" "flour"))) @@ -136,6 +125,7 @@ whitespace characters and then consumes an object or a quantity. > , cmpOperation ">dough" (Right (Result "dough")) > , cmpOperation "|trimmings" (Right (Alternative "trimmings")) > , cmpOperation "*fish" (Right (Reference (Quantity (Exact (AmountStr "")) "" "fish"))) +> , cmpOperation3 "% invalid" (Right (Directive "invalid")) "%invalid" > , cmpOperation3 "* \t\n 1 _ cheese" (Right (Reference (Quantity (Exact (AmountRatio (1%1))) "" "cheese"))) "*1 _ cheese" > ] @@ -155,6 +145,7 @@ A word always starts with a letter, followed by any number of non-space characters. > word = (:) <$> letter <*> many notspace +> notspace = satisfy (not . isSpace) The empty string can be represented by two double quotes or the underscore, but not the empty string itself. @@ -347,7 +338,7 @@ Appendix ++++++++ > int = read <$> many1 digit -> parse = runParser recipe () "" +> parse = runParser stream () "" Test helpers: @@ -394,4 +385,8 @@ Wrap qstr test in AmountStr to aid serialization test > isAnnotation _ = False > isAction (Action _) = True > isAction _ = False +> isDirective (Directive _) = True +> isDirective _ = False +> isUnknown (Unknown _) = True +> isUnknown _ = False |