diff options
Diffstat (limited to 'src/Codec/Pesto/Parse.lhs')
| -rw-r--r-- | src/Codec/Pesto/Parse.lhs | 78 |
1 files changed, 40 insertions, 38 deletions
diff --git a/src/Codec/Pesto/Parse.lhs b/src/Codec/Pesto/Parse.lhs index 7deb511..0d4e981 100644 --- a/src/Codec/Pesto/Parse.lhs +++ b/src/Codec/Pesto/Parse.lhs @@ -6,7 +6,7 @@ Language syntax > module Codec.Pesto.Parse ( > parse > , test -> , Operation(..) +> , Instruction(..) > , Quantity(..) > , Unit(..) > , Object(..) @@ -34,23 +34,20 @@ Language syntax > > import Codec.Pesto.Serialize (serialize) -Pesto parses UTF-8_ encoded input files into a sequence of operations. - -- stream of operations -- utf8 encoded -Every -character within the Unicode whitespace class is considered a space. +Pesto parses UTF-8_ encoded input data consisting of space-delimited +instructions. Every character within the Unicode whitespace class is +considered a space. .. _UTF-8: https://tools.ietf.org/html/rfc3629 .. _spaces1: -> stream = ((,) <$> getPosition <*> operation) `sepEndBy` spaces1 +> stream = ((,) <$> getPosition <*> instruction) `sepEndBy` spaces1 > <?> "stream" > spaces1 = many1 space -The following operations are supported: +The following instructions are supported: -> data Operation = +> data Instruction = > Annotation String > | Ingredient Quantity > | Tool Quantity @@ -62,7 +59,7 @@ The following operations are supported: > | Unknown String > deriving (Show, Eq) > -> operation = +> instruction = > try annotation > <|> try ingredient > <|> try tool @@ -72,28 +69,27 @@ The following operations are supported: > <|> try reference > <|> try directive > <|> try unknown -> <?> "operation" +> <?> "instruction" -The pesto grammar has two kinds of operations: The first one begins with a -start character and consumes characters up to and including a terminating -symbol (``end``), which can be escaped with a backslash (``\``): +The pesto grammar has two instruction types: The first one begins with a +start symbol (``start``) and consumes any character up to and including a +terminating symbol (``end``), which can be escaped with a backslash (``\``). > betweenEscaped start end = > char start > *> many (try (char '\\' *> char end) <|> satisfy (/= end)) > <* char end -Annotations and Actions both are of this kind: +Annotations and actions both are of this kind: > annotation = Annotation <$> betweenEscaped '(' ')' > action = Action <$> betweenEscaped '[' ']' Here are examples for both: -> testOpterm = [cmpOperation "(skinless\nboneless)" (Right (Annotation "skinless\nboneless")) -> , cmpOperation "[stir together]" (Right (Action "stir together")) -> , cmpOperation "[stir\\]together]" (Right (Action "stir]together"))] - +> testOpterm = [cmpInstruction "(skinless\nboneless)" (Right (Annotation "skinless\nboneless")) +> , cmpInstruction "[stir together]" (Right (Action "stir together")) +> , cmpInstruction "[stir\\]together]" (Right (Action "stir]together"))] The second one starts with one identifying character, ignores the following whitespace characters and then consumes an object or a quantity. @@ -105,28 +101,34 @@ 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. +Additionally there are two special instructions. Directives are similar to the +previous instructions, but consume a qstr. > directive = oparg '%' (Directive <$> qstr) -Unknown operations are the fallthrough-case and accept anything. They must not -be discarded at this point. The point of accepting anything is to fail as late -as possible while processing Pesto documents. This gives us a chance to print -helpful mesages that provide additional aid to the user who can then fix the -problem. +Unknown instructions are the fallthrough-case and accept anything. They must +not be discarded at this point. The point of accepting anything is to fail as +late as possible while processing input. This gives the parser a chance to +print helpful mesages that provide additional aid to the user who can then fix +the problem. > unknown = Unknown <$> many1 notspace +Below are examples for these instructions: + > testOparg = [ -> cmpOperation "+100 g flour" (Right (Ingredient (Quantity (Exact (AmountRatio (100%1))) "g" "flour"))) - -> , cmpOperation "&oven" (Right (Tool (Quantity (Exact (AmountStr "")) "" "oven"))) -> , 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" +> cmpInstruction "+100 g flour" +> (Right (Ingredient (Quantity (Exact (AmountRatio (100%1))) "g" "flour"))) +> , cmpInstruction "&oven" +> (Right (Tool (Quantity (Exact (AmountStr "")) "" "oven"))) +> , cmpInstruction ">dough" (Right (Result "dough")) +> , cmpInstruction "|trimmings" (Right (Alternative "trimmings")) +> , cmpInstruction "*fish" +> (Right (Reference (Quantity (Exact (AmountStr "")) "" "fish"))) +> , cmpInstruction3 "% invalid" (Right (Directive "invalid")) "%invalid" +> , cmpInstruction3 "* \t\n 1 _ cheese" +> (Right (Reference (Quantity (Exact (AmountRatio (1%1))) "" "cheese"))) +> "*1 _ cheese" > ] Qstr @@ -207,7 +209,7 @@ the usual escape codes like \\n, \\t, … will *not* be expanded. Quantity ++++++++ -The operations Ingredient, Tool and Reference accept a *quantity*, that is a +The instructions Ingredient, Tool and Reference accept a *quantity*, that is a triple of Approximately, Unit and Object as parameter. > data Quantity = Quantity Approximately Unit Object deriving (Show, Eq) @@ -363,8 +365,8 @@ Wrap qstr test in AmountStr to aid serialization test > cmpQuantity a b = cmpQuantity3 a b a > cmpQuantity3 = cmpParseSerialize quantity -> cmpOperation a b = cmpOperation3 a b a -> cmpOperation3 = cmpParseSerialize operation +> cmpInstruction a b = cmpInstruction3 a b a +> cmpInstruction3 = cmpParseSerialize instruction > exactQuantity a b c = Right (Quantity (Exact a) b c) |