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Diffstat (limited to 'src/lib')
| -rw-r--r-- | src/lib/Codec/Pesto.lhs | 283 | ||||
| -rw-r--r-- | src/lib/Codec/Pesto/Graph.lhs | 301 | ||||
| -rw-r--r-- | src/lib/Codec/Pesto/Lint.lhs | 466 | ||||
| -rw-r--r-- | src/lib/Codec/Pesto/Parse.lhs | 412 | ||||
| -rw-r--r-- | src/lib/Codec/Pesto/Parse.lhs-boot | 22 | ||||
| -rw-r--r-- | src/lib/Codec/Pesto/Serialize.lhs | 66 |
6 files changed, 1550 insertions, 0 deletions
diff --git a/src/lib/Codec/Pesto.lhs b/src/lib/Codec/Pesto.lhs new file mode 100644 index 0000000..ba8e332 --- /dev/null +++ b/src/lib/Codec/Pesto.lhs @@ -0,0 +1,283 @@ +============================ +Pesto language specification +============================ + +Pesto is a text-based, human-editable, and machine-transformable cooking recipe +interchange format. + +.. class:: nodoc + +> module Codec.Pesto where + +About this document +------------------- + +This section contains various information about this document. The `second +section`__ motivates why inventing another file format is necessary, followed +by the goals__ of Pesto. After a short Pesto primer__ for the casual +user, the language’s syntax__ and semantics__ are presented. The `linting +section`__ limits the language to useful cooking recipes. Examples for user +presentation of recipes and serialization follow. + +__ #motivation +__ #goals +__ #introduction-by-example +__ #language-syntax +__ #language-semantics +__ #linting + +Being a literate program, this document is specification and reference +implementation simultaneously. The code is written in Haskell_ and uses the +parsec_ parser combinator library, as well as HUnit_ for unit tests. Even +without knowing Haskell’s syntax, you should be able to understand this +specification. There’s a description above every code snippet explaining what +is going on. + +.. _Haskell: http://learnyouahaskell.com/ +.. _HUnit: http://hackage.haskell.org/package/HUnit +.. _parsec: http://hackage.haskell.org/package/parsec + +The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, +“SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be +interpreted as described in `RFC 2119`_. + +.. _RFC 2119: http://tools.ietf.org/html/rfc2119 + +:Version: 1-draft +:License: CC0_ +:Website: https://6xq.net/pesto/ +:Source code: https://codeberg.org/ldb/pesto + +.. _CC0: https://creativecommons.org/publicdomain/zero/1.0/ + +.. _motivation: + +Motivation +---------- + +The landscape of recipe interchange formats is quite fragmented. First, +there’s HTML microdata: `Google rich snippets`_, equivalent to the +schema.org_ microdata vocabulary, are widely used by commercial recipe sites. +Although the main objective of microdata is to make content machine-readable +most sites will probably use it because it is considered a search-engine +optimization (SEO) and not a method for sharing recipes. h-recipe_ provides a +second vocabulary that has not been adopted widely yet. + +.. _Google rich snippets: https://developers.google.com/structured-data/rich-snippets/recipes +.. _schema.org: http://schema.org/Recipe +.. _h-recipe: http://microformats.org/wiki/h-recipe + +.. _formats-by-software: + +Most cooking-related software comes with custom recipe file formats. Some +of them can be imported by other programs. Meal-Master_ is one of these +widely supported formats. A vast trove of recipe files is `available in +this format <http://www.ffts.com/recipes.htm>`_. There does not seem +to be any official documentation for the format, but inofficial `ABNF +grammar`_ and `format description <http://www.ffts.com/mmformat.txt>`_ +exist. A Meal-Master recipe template might look like this: + +.. _MasterCook: http://mastercook.com/ +.. _MXP: http://www.oocities.org/heartland/woods/2073/Appendix.htm +.. _ABNF grammar: http://web.archive.org/web/20161002135718/http://www.wedesoft.de/anymeal-api/mealmaster.html + +.. code:: mealmaster + + ---------- Recipe via Meal-Master (tm) + + Title: <Title> + Categories: <Categories> + Yield: <N servings> + + <N> <unit> <ingredient> + … + + -------------------------------<Section name>----------------------------- + <More ingredients> + + <Instructions> + + ----- + +Rezkonv_ aims to improve the Mealmaster format by lifting some of its character +limits, adding new syntax, and translating it to german. However, the +specification is available on request only. + +A second format some programs can import is MasterCook_’s MXP_ file +format and its XML-based successor, MX2. Beyond that there exist numerous +application-specific, proprietary formats: + +`Living Cookbook`_ + Uses a XML-based format called fdx version 1.1. There’s no specification to + be found, but a few + `examples <http://livingcookbook.com/Resource/DownloadableRecipes>`_ + are available, and those are dated 2006. +`My CookBook`_ + Uses the file extension .mcb. A specification `is available + <http://mycookbook-android.com/site/my-cookbook-xml-schema/>`_. +KRecipes_ + Uses its own export format. However, there is no documentation whatsoever. +Gourmet_ + The program’s export format suffers from the same problem. The only + document available is the `DTD + <https://github.com/thinkle/gourmet/blob/7715c6ef87ee8c106f0a021972cd70d61d83cadb/data/recipe.dtd>`_. +CookML_ + Last updated in 2006 (version 1.0.4) for the german-language shareware + program Kalorio has a custom and restrictive license that requires + attribution and forbids derivate works. +Paprika_ + Cross-platform application which supports its own “emailed recipe format” and a + simple YAML-based format. + +.. _Paprika: https://paprikaapp.com/help/android/#importrecipes + +.. _xml-formats: + +Between 2002 and 2005, a bunch of XML-based exchange formats were created. They +are not tied to specific software, so none of them seems to be actively used +nowadays: + +RecipeML_ + Formerly known as DESSERT and released in 2002 (version 0.5). The + license requires attribution and – at the same time – forbids using the name + RecipeML for promotion without written permission. +eatdrinkfeelgood_ + Version 1.1 was released in 2002 as well, but the site is not online + anymore. The DTD is licensed under the `CC by-sa`_ license. +REML_ + Released in 2005 (version 0.5), aims to improve support for commercial uses + (restaurant menus and cookbooks). The XSD’s license allows free use and + redistribution, but the reference implementation has no licensing + information. +`RecipeBook XML`_ + Released 2005 as well and shared under the terms of `CC by-sa`_ is not + available on the web anymore. + +.. _CC by-sa: https://creativecommons.org/licenses/by-sa/2.5/ + +.. _obscure-formats: + +Finally, a few non-XML or obscure exchange formats have been created in the past: +YumML_ is an approach similar to those listed above but based on YAML instead +of XML. The specification has been removed from the web and is available +through the Web Archive only. + +`Cordon Bleu`_ (1999) encodes recipes as programs for a cooking machine and +defines a Pascal-like language. Being so close to real programming languages, +Cordon Bleu is barely usable by anyone except programmers. Additionally, the +language is poorly-designed since its syntax is inconsistent, and the user is +limited to a set of predefined functions. + +Finally, there is RxOL_, created in 1985. It constructs a graph from recipes +written down with a few operators and postfix notation, and does not separate +ingredients and cooking instructions like every other syntax introduced before. +Although Pesto is not a direct descendant of RxOL both share many ideas. + +microformats.org_ has a similar list of recipe interchange formats. + +.. _REML: http://reml.sourceforge.net/ +.. _eatdrinkfeelgood: https://web.archive.org/web/20070109085643/http://eatdrinkfeelgood.org/1.1/ +.. _RecipeML: http://www.formatdata.com/recipeml/index.html +.. _CookML: http://www.kalorio.de/index.php?Mod=Ac&Cap=CE&SCa=../cml/CookML_EN +.. _Meal-Master: http://web.archive.org/web/20151029032924/http://episoft.home.comcast.net:80/~episoft/ +.. _RecipeBook XML: http://web.archive.org/web/20141101132332/http://www.happy-monkey.net/recipebook/ +.. _YumML: http://web.archive.org/web/20140703234140/http://vikingco.de/yumml.html +.. _Rezkonv: http://www.rezkonv.de/software/rksuite/rkformat.html +.. _RxOL: http://web.archive.org/web/20150814041516/www.dodomagnifico.com/641/Recipes/CompCook.html +.. _Gourmet: http://thinkle.github.io/gourmet/ +.. _KRecipes: http://krecipes.sourceforge.net/ +.. _Cordon Bleu: http://web.archive.org/web/20090115210732/http://www.inf.unideb.hu/~bognar/ps_ek/cb_lang.ps +.. _microformats.org: http://microformats.org/wiki/recipe-formats +.. _Living Cookbook: http://livingcookbook.com/ +.. _My CookBook: http://mycookbook-android.com/ + +.. There is a copy at http://diyhpl.us/~bryan/papers2/CompCook.html as well + +.. More interesting stuff: +.. - http://blog.moertel.com/posts/2010-01-08-a-formal-language-for-recipes-brain-dump.html +.. - http://www.dangermouse.net/esoteric/chef.html + +.. _goals: + +Goals +----- + +First of all, recipes are written *by* humans *for* humans. Thus a +human-readable recipe interchange format is not enough. The recipes need +to be human-editable without guidance like a GUI or assistant. That’s +why, for instance, XML is unsuitable, and the interchange formats listed +`above <xml-formats_>`_ have largely failed to gain traction. Even though +simple, XML is still too complicated for the ordinary user. Instead, +a format needs to be as simple as possible, with as little markup as +possible. A human editor must be able to remember the entire syntax. This +works best if the file contents “make sense.” An excellent example +of this is Markdown_. + +.. _Markdown: https://daringfireball.net/projects/markdown/syntax + +We also must acknowledge that machines play an important role in our +daily lives. They can help us, the users, accomplish our goals if they +can also understand the recipes. Thus they, too, need to be able to +read and write recipes. Again, designing a machine-readable format is +not enough. Recipes must be machine-transformable. A computer program +should be able to create a new recipe from two existing ones, look up +the ingredients and tell us how many joules one piece of that cake will +have. And so on. + +That being said, Pesto does not aim to carry additional information about +ingredients or recipes themselves. Nutrition data for each ingredient +should be maintained in a separate database. Due to its minimal syntax, +Pesto is also not suitable for extensive guides on cooking or the usual +chitchat found in cooking books. + +.. _introduction-by-example: + +Introduction by example +----------------------- + +.. code:: + + So let’s start by introducing Pesto by example. This text does not belong + to the recipe and is ignored by any software. The following line starts the + recipe: + + %pesto + + &pot + +1 l water + +salt + [boil] + + +100 g penne + &10 min + [cook] + + >1 serving pasta + (language: en) + +And that’s how you make pasta: Boil one liter of water in a pot with a little +bit of salt. Then add 100 g penne, cook them for ten minutes, and you get one +serving pasta. That’s all. + +There’s more syntax available to express alternatives (either penne or +tagliatelle), ranges (1–2 l water or approximately 1 liter water), and metadata. +But now you can have a first peek at `my recipe collection`_. + +.. _my recipe collection: https://codeberg.org/ldb/rezepte + +.. include:: Pesto/Parse.lhs +.. include:: Pesto/Graph.lhs +.. include:: Pesto/Lint.lhs +.. include:: Pesto/Serialize.lhs + +Using this project +------------------ + +This project uses cabal. It provides the ``Codec.Pesto`` library that implements +the Pesto language as described in the previous sections. It also comes with +three binaries. + +.. include:: ../../exe/Main.lhs +.. include:: ../../exe/Test.lhs +.. include:: ../../exe/Doc.lhs + diff --git a/src/lib/Codec/Pesto/Graph.lhs b/src/lib/Codec/Pesto/Graph.lhs new file mode 100644 index 0000000..43142b6 --- /dev/null +++ b/src/lib/Codec/Pesto/Graph.lhs @@ -0,0 +1,301 @@ +.. _language-semantics: + +Language semantics +------------------ + +.. class:: nodoc + +> module Codec.Pesto.Graph ( +> toGraph +> , walkRoot +> , outgoingEdges +> , outgoingNodes +> , incomingEdges +> , incomingNodes +> , firstNodeId +> , resolveReferences +> , test +> , extract +> , NodeId +> , Node +> , Nodes +> , Edge +> , Edges +> ) where +> import Data.Char (toLower) +> import Data.List (sort, nub) +> import Test.HUnit hiding (test, Node) +> +> import Codec.Pesto.Parse hiding (test) + +The parser’s output, a stream of instructions, may contain multiple recipes. A +recipe must start with the directive “pesto” and may end with +“buonappetito”, which allows embedding recipes into other (plain-text) +documents. This function extracts all recipes from the stream and removes +both directives. + +> startDirective = Directive "pesto" +> endDirective = Directive "buonappetito" + +> extract [] = [] +> extract (s:stream) | s == startDirective = between:extract next +> where +> isEnd x | x `elem` [startDirective, endDirective] = True +> isEnd _ = False +> (between, next) = break isEnd stream +> extract (_:xs) = extract xs + +Start and end directives are removed from the extracted instructions. The +directive “buonappetito” is optional at the end of a stream. + +> testExtract = [ +> extract [startDirective, endDirective] ~?= [[]] +> , extract [startDirective, Action "foobar", endDirective] ~?= [[Action "foobar"]] +> , extract [startDirective] ~?= [[]] +> , extract [startDirective, Directive "foobar"] ~?= [[Directive "foobar"]] + +Instructions surrounding the start and end directive are removed. + +> , extract [Unknown "Something", startDirective] ~?= [[]] +> , extract [Unknown "Something", Action "pour", startDirective] ~?= [[]] +> , extract [startDirective, endDirective, Annotation "something"] ~?= [[]] + +The stream may contain multiple recipes. The start directive also ends the +previous recipe and starts a new one. + +> , extract [ +> startDirective +> , Action "pour" +> , endDirective +> , Action "foobar" +> , startDirective +> , Annotation "something"] +> ~?= [[Action "pour"], [Annotation "something"]] +> , extract [ +> startDirective +> , Action "heat" +> , startDirective +> , Annotation "something"] +> ~?= [[Action "heat"], [Annotation "something"]] +> , extract [ +> startDirective +> , Annotation "foobar" +> , startDirective +> , endDirective] +> ~?= [[Annotation "foobar"], []] +> ] + +Each recipe’s stream of instructions drives a stack-based machine that transforms +it into a directed graph. Think of the stack as your kitchen’s workspace that +is used to prepare the food’s components. You can add new ingredients, perform +actions on them, put them aside, and add them again. + +This function processes a list of nodes, that is, instructions uniquely identified +by an integer, and returns the edges of the directed graph as a list of tuples. + +> toGraph :: Nodes Instruction -> Edges +> toGraph nodes = third $ foldl f (Nothing, [[]], []) nodes +> where + +Ingredients are simply added to the current workspace. They should, for example, +appear on the shopping list. + +> f ctx (i, Ingredient _) = addToStack ctx i + +The same happens for tools. However, they are not part of the final product +but are used in the process of making it. Thus, they do not appear on the +shopping list. `Time is considered a tool <#time-is-a-tool>`_. + +> f ctx (i, Tool _) = addToStack ctx i + +Actions take all ingredients and tools currently on the workspace, perform some +action with them, and put the product back onto the workspace. + +> f (_, stack:sx, edges) (i, Action _) = (Just i, [i]:stack:sx, edgesTo i stack ++ edges) +> f (_, [], _) (_, Action _) = undefined -- never reached + +Results add a label to the current workspace’s contents and move them out of +the way. It should be a meaningful name, not just A and B. +Consecutive results add different labels to the same workspace. That’s useful +when an action yields multiple results at once that are processed in different +ways. + +> f ctx (i, Result _) = consumeStack ctx i + +Alternatives, too, add a label to the current workspace’s content, but they pick +one of the things on the workspace and throw everything else away. This allows +adding optional or equivalent ingredients to a recipe (i.e., margarine or butter). + +> f ctx (i, Alternative _) = consumeStack ctx i + +References are similar to ingredients. They are used to add items from a +workspace labeled with ``Result`` or ``Alternative``. More on that `in the next section +<#references>`_. + +> f ctx (i, Reference _) = addToStack ctx i + +Annotations add a description to any of the previous instructions. They can be +used to provide more information about ingredients (so “hot water” becomes +``+water (hot)``, tools (``&oven (200 °C)``), or actions (``[cook] +(until brown)``). + +> f ctx@(Nothing, _, _) (_, Annotation _) = ctx +> f (Just prev, s, edges) (i, Annotation _) = (Just prev, s, (i, prev):edges) + +Unused directives or unknown instructions are danging nodes with no connection to +other nodes. + +> f ctx (_, Directive _) = ctx +> f ctx (_, Unknown _) = ctx + +These are helper functions: + +> addToStack (_, stack:sx, edges) i = (Just i, (i:stack):sx, edges) +> addToStack (_, [], _) _ = undefined -- never reached +> consumeStack (_, s, edges) i = +> let +> stack = dropWhile null s +> (top:sx) = if null stack then [[]] else stack +> in (Just i, []:top:sx, edgesTo i top ++ edges) +> edgesTo i = map (\x -> (x, i)) + +Here are a few examples of how this stack-machine works. Each edge is a tuple of +two integer numbers. These are the nodes it connects, starting with zero. +``Ingredient``, ``Tool``, and ``Reference`` itself do not create any edges: + +> testGraph = [ +> cmpGraph "+ketchup &spoon *foobar" [] + +But ``Action``, ``Alternative`` and ``Result`` do in combination with them: + +> , cmpGraph "+foobar [barbaz]" [(0, 1)] +> , cmpGraph "+foobar |barbaz" [(0, 1)] +> , cmpGraph "+foobar >barbaz" [(0, 1)] +> , cmpGraph "+foobar +B >barbaz" [(0, 2), (1, 2)] +> , cmpGraph "+foobar >barbaz +foobar >barbaz" [(0, 1), (2, 3)] +> , cmpGraph "+foobar [barbaz] +foobar >barbaz" [(0, 1), (1, 3), (2, 3)] +> , cmpGraph "&foobar [barbaz] [C] >D" [(0, 1), (1, 2), (2, 3)] + +If the stack is empty, i.e. it was cleared by a ``Result`` or ``Alternative`` +instruction, consecutive results or alternatives operate on the *previous*, +non-empty stack. + +> , cmpGraph "+foobar >barbaz >C" [(0, 1), (0, 2)] +> , cmpGraph "+foobar >barbaz >C >D" [(0, 1), (0, 2), (0, 3)] +> , cmpGraph "+foobar |barbaz |C" [(0, 1), (0, 2)] +> , cmpGraph "+foobar >barbaz |C" [(0, 1), (0, 2)] + +Unless that stack too is empty. Then they do nothing: + +> , cmpGraph ">foobar >foobar" [] +> , cmpGraph "|foobar |foobar" [] +> , cmpGraph "(foobar) (foobar)" [] +> , cmpGraph "[foobar]" [] + +The ``Annotation`` instruction always creates an edge to the most-recently processed +node that was not an annotation. Thus two consecutive annotations create edges +to the same node. + +> , cmpGraph "+foobar (barbaz)" [(1, 0)] +> , cmpGraph "+foobar (barbaz) (C)" [(1, 0), (2, 0)] +> , cmpGraph "+foobar (barbaz) >barbaz" [(1, 0), (0, 2)] +> , cmpGraph "+foobar >barbaz (C)" [(0, 1), (2, 1)] +> , cmpGraph "+foobar |barbaz (C)" [(0, 1), (2, 1)] +> , cmpGraph "*foobar (C)" [(1, 0)] + +Unknown directives or instructions are never connected to other nodes. + +> , cmpGraph "%invalid" [] +> , cmpGraph "invalid" [] +> ] + +.. _references: + +References +++++++++++ + +Results and alternatives can be referenced with the ``Reference`` instruction. +Resolving these references does not happen while building the graph but +afterward. This allows referencing a result or alternative before its +definition with regard to their processing order. + +Resolving references is fairly simple: For every reference’s object name, a +case-insensitive lookup is performed in a table containing all results and +alternatives. If it succeeds, an edge from every result and alternative returned +to the reference in question is created. + +> resolveReferences :: Nodes Instruction -> Edges +> resolveReferences nodes = foldl f [] nodes +> where +> f edges (i, ref@(Reference _)) = map (\x -> (x, i)) (findTargets nodes ref) ++ edges +> f edges _ = edges + +> findTargets :: Nodes Instruction -> Instruction -> [NodeId] +> findTargets nodes (Reference (Quantity _ _ a)) = map fst $ filter (isTarget a) nodes +> where +> lc = map toLower +> isTarget dest (_, Result (Quantity _ _ x)) = lc x == lc dest +> isTarget dest (_, Alternative (Quantity _ _ x)) = lc x == lc dest +> isTarget _ _ = False +> findTargets _ _ = [] + +References are position-independent and can be used before or after the +result instruction they are referencing. + +> testRef = [ +> cmpGraphRef ">foobar *foobar" [(0, 1)] +> , cmpGraphRef ">foobar |foobar *foobar" [(0, 2), (1, 2)] +> , cmpGraphRef "+A >foobar +B >barbaz *foobar *barbaz" [(1, 4), (3, 5)] +> , cmpGraphRef "*foobar >foobar" [(1, 0)] + +Nonexistent references do not create an edge. + +> , cmpGraphRef ">foobar *barbaz" [] + +References can use amounts and units. + +> , cmpGraphRef ">foobar *1 _ foobar *2 _ foobar" [(0, 1), (0, 2)] + +There are a few cases that do not make sense here (like loops or multiple +results with the same name). They are permitted at this stage, but rejected +`later <#reject-loops>`_. + +> , cmpGraphRef "*foobar |foobar >foobar" [(1, 0), (2, 0)] +> , cmpGraphRef "|foobar *foobar >foobar *foobar" [(0, 1), (0, 3), (2, 1), (2, 3)] +> ] + +Appendix +++++++++ + +> runGraphWith f doc expect = sort edges ~?= sort expect +> where +> (Right op) = (head . extract . snd . unzip) <$> parse ("%pesto " ++ doc) +> nodes = zip [firstNodeId..] op +> edges = f nodes +> cmpGraph = runGraphWith toGraph +> cmpGraphRef = runGraphWith resolveReferences + +> type NodeId = Int +> type Node a = (NodeId, a) +> type Nodes a = [Node a] +> type Edge = (NodeId, NodeId) +> type Edges = [Edge] +> firstNodeId = 0 :: NodeId + +Find graph’s root node(s), that is a node without outgoing edges: + +> walkRoot nodes edges = let out = nub $ map fst edges +> in filter (\(x, _) -> notElem x out) nodes + +Get all nodes with edges pointing towards nodeid + +> incomingEdges edges nodeid = filter ((==) nodeid . snd) edges +> incomingNodes nodes edges nodeid = map ((!!) nodes . fst) $ incomingEdges edges nodeid + +> outgoingEdges edges nodeid = filter ((==) nodeid . fst) edges +> outgoingNodes nodes edges nodeid = map ((!!) nodes . snd) $ outgoingEdges edges nodeid + +> test = ["graph" ~: testGraph, "ref" ~: testRef, "extract" ~: testExtract] + +> third (_, _, x) = x + diff --git a/src/lib/Codec/Pesto/Lint.lhs b/src/lib/Codec/Pesto/Lint.lhs new file mode 100644 index 0000000..3ecdfa1 --- /dev/null +++ b/src/lib/Codec/Pesto/Lint.lhs @@ -0,0 +1,466 @@ +.. _linting: + +Linting +------- + +.. class:: nodoc + +> module Codec.Pesto.Lint (lint +> , test +> , parseMetadata +> , extractMetadata +> , Metadata(..) +> , LintResult(..)) where +> import Test.HUnit hiding (test, Node) +> import Data.List (sort, isPrefixOf, insert, intersect) +> import Text.Parsec hiding (parse) +> import Data.Char (isSpace, toLower) +> import Data.Ratio ((%)) +> import Data.Maybe (fromMaybe) +> import qualified Data.Map.Strict as M +> +> import Codec.Pesto.Graph hiding (test) +> import Codec.Pesto.Parse hiding (test) + +Not every graph generated in the previous section is a useful recipe. Some +instruction sequences just do not make sense. The tests in this section can +detect those. Failing any of them does not render a stream of instructions or +graph invalid. They just do not describe a *useful* recipe. Thus +implementations must not generate or export such documents. However, they should +accept input that fails any of the tests and warn the user about the failure. + +Additionally, this section provides guidance on how to use the instructions +provided by the Pesto language properly. + +Graph properties +++++++++++++++++ + +.. _resultsused: + +The graph must have exactly one root node (i.e., a node with incoming edges +only). This also requires all results and alternatives to be referenced +somewhere. Directives are either consumed when parsing, generating a graph, and +linting. Otherwise they are dangling as well. Unknown instructions are always +dangling. + +> rootIsResult nodes edges = case walkRoot nodes edges of +> [] -> [LintResult NoRootNode []] +> (_, Result _):[] -> [] +> (i, _):[] -> [LintResult NonResultRootNode [i]] +> xs -> [LintResult MoreThanOneRootNode (map fst xs)] + +Empty recipes or circular references have no root node: + +> testConnectivity = [ +> cmpLint "" [LintResult NoRootNode [], LintResult NoMetadata []] +> , cmpLint "*foobar >foobar" +> [LintResult NoRootNode [], LintResult CircularLoop [0, 1], LintResult NoMetadata []] +> , cmpLint "+foobar" +> [LintResult NonResultRootNode [0], LintResult NoMetadata []] + +Directives and unknown instructions are dangling and thus root nodes. + +> , cmpLint "invalid %invalid +foo >bar" +> [LintResult MoreThanOneRootNode [0,1,3], LintResult NoMetadata []] +> ] + +Metadata +++++++++ + +The graph’s root node must be a result. It contains yield (amount and unit) and +title (object) of the recipe. + +> extractMetadata nodes edges = case walkRoot nodes edges of +> [(i, Result q@(Quantity _ _ title))] -> +> Just $ (i, ("title", MetaStr title)) +> :(i, ("yield", MetaQty q)) +> :foldl f [] (incomingNodes nodes edges i) +> _ -> Nothing +> where + +Additional key-value metadata for the whole recipe can be added as annotations +to the root node. If multiple annotations with the same key exist, the key maps +to a list of those values. Annotations that are unparseable key-value pairs are +added as recipe description instead. + +> f xs (i, Annotation s) = case parseMetadata s of +> Left _ -> (i, ("description", MetaStr s)):xs +> Right (k, v) -> (i, (k, MetaStr v)):xs +> f xs _ = xs + +Key and value are separated by a colon. Keys must not contain whitespace or the +colon char. A value may be empty. + +> parseMetadata = runParser metadata () "" +> metadata = let keychars = satisfy (\x -> not (isSpace x) && x /= ':') in (,) +> <$> many1 keychars +> <*> (char ':' *> spaces *> many anyChar) + +> lintMetadata nodes edges = case extractMetadata nodes edges of +> Just result -> foldl checkKey [] result +> Nothing -> [LintResult NoMetadata []] +> where +> checkKey xs (_, (k, _)) | isKeyKnown k = xs +> checkKey xs (i, _) = LintResult UnknownMetadataKey [i]:xs + +Valid metadata keys are listed below. Additionally, applications may add keys by +prefixing them with “x-myapp-”. Thus an application called “basil” adding +“some-key” would use the full key “x-basil-some-key”. + +> isKeyKnown k = k `elem` knownKeys || "x-" `isPrefixOf` k + +The following metadata keys are permitted: + +> knownKeys = [ + +The title, description and yield are implicit. + +> "title" +> , "description" +> , "yield" + +The recipe’s language, as 2 character code (`ISO 639-1 +<http://www.loc.gov/standards/iso639-2/php/English_list.php>`_). + +> , "language" + +Time both must be a time-unit quantity. + +> , "time" + +An image can be a relative file reference or URI + +> , "image" +> , "author" +> ] + +For instance a german language recipe for one person would look like this: + +> testMetadata = [ +> cmpLintMeta "+foo >1 _ foobar (language: de) (x-app-key: value)" +> [] +> (Just [(1, ("title", MetaStr "foobar")) +> , (1, ("yield", MetaQty (Quantity (Exact (AmountRatio (1%1))) "" "foobar"))) +> , (2, ("language", MetaStr "de")) +> , (3, ("x-app-key", MetaStr "value"))]) + +Unparseable annotations or unknown keys are linting errors: + +> , cmpLintMeta "+foo >foobar (unknown-key: value)" +> [LintResult UnknownMetadataKey [2]] +> (Just [(1, ("title", MetaStr "foobar")) +> , (1, ("yield", MetaQty (strQuantity "foobar"))) +> , (2, ("unknown-key", MetaStr "value"))]) + +Root node annotations not containing a parseable key-value pair are assigned +the key “description”. + +> , cmpLintMeta "+foo >foobar ( some description ) (another one: with colon) (another: valid key-value)" +> [LintResult UnknownMetadataKey [4]] +> (Just [(1, ("title", MetaStr "foobar")) +> , (1, ("yield", MetaQty (strQuantity "foobar"))) +> , (2, ("description", MetaStr " some description ")) +> , (3, ("description", MetaStr "another one: with colon")) +> , (4, ("another", MetaStr "valid key-value"))]) +> ] + +.. _time-is-a-tool: + +Time is a tool +++++++++++++++ + +By definition, time is a tool and not an ingredient. + +> timeUnits = ["s", "min", "h", "d"] +> +> isTime (Quantity _ unit "") | unit `elem` timeUnits = True +> isTime _ = False + +> timeIsATool nodes _ = foldl f [] nodes +> where +> f xs (nodeid, Ingredient q) | isTime q = LintResult TimeIsATool [nodeid]:xs +> f xs _ = xs + +> testLintQuantity = [ +> cmpLint "+10 min >foo" [LintResult TimeIsATool [0]] +> , cmpLint "+10-12 h >foo" [LintResult TimeIsATool [0]] +> , cmpLint "+90/120 s >foo" [LintResult TimeIsATool [0]] +> , cmpLint "+~12 s >foo" [LintResult TimeIsATool [0]] +> , cmpLint "&10 min [bar] >foo" [] +> ] + +Only actions can be annotated like this. It can be used to indicate how long +a particular action is *expected* to take (i.e., peeling potatoes takes two +minutes) or how long the action is supposed to be executed (i.e. cook for five +minutes). More time annotations improve the software’s scheduling capabilities. + +> timeAnnotatesAction nodes edges = foldl f [] nodes +> where +> f xs (nodeid, Tool q) | isTime q && (not . allActions) (outgoingEdges edges nodeid) = LintResult TimeAnnotatesAction [nodeid]:xs +> f xs _ = xs +> toNodelist = (!!) nodes . snd +> allActions = all (isAction . snd . toNodelist) + +For example, “cook 10 minutes” can be expressed with: + +> testTimeAnnotatesAction = [ +> cmpLint "&10 min [cook] >soup" [] +> , cmpLint "&10 min [cook] &5-6 h [cook again] >soup" [] +> , cmpLint "&10 min >soup" [LintResult TimeAnnotatesAction [0]] +> , cmpLint "&10 min &15 min |time *time [cook] >soup" +> [LintResult TimeAnnotatesAction [0], LintResult TimeAnnotatesAction [1]] +> ] + +.. _well-known-units: + +Well-known units +++++++++++++++++ + +Units can be arbitrary strings, but implementations should recognize the +standard metric units g (gram), l (liter), and m (meter). One of these prefixes +may be used with each of them: m (milli-), c (centi-), d (dezi-), and k (kilo-). +Additionally, time in s (second), min (minute), h (hour), and d (day) should be +accepted. + +> wellKnownUnit nodes _ = foldl f [] nodes +> where +> extractQty (Ingredient q) = Just q +> extractQty (Tool q) = Just q +> extractQty (Result q) = Just q +> extractQty (Alternative q) = Just q +> extractQty (Reference q) = Just q +> extractQty _ = Nothing +> f xs (nodeid, instr) | fromMaybe False (extractQty instr >>= (return . not . known)) = +> LintResult UnitNotWellKnown [nodeid]:xs +> f xs _ = xs +> known (Quantity _ unit _) = unit `elem` knownUnits +> knownUnits = [ +> "" +> , "mg", "g", "kg" +> , "ml", "cl", "dl", "l" +> , "cm", "dm", "m" +> ] ++ timeUnits + +Usage of imperial units (inch, pound, …), non-standard +units like “teaspoon,” “cup,” or similar is discouraged because +the former is used by just three countries in the world right now, and +the latter is language- and country-dependent. The implementation may +provide the user with a conversion utility. + +> testLintWellKnownUnit = [ +> cmpLint "+1 in foobar >bar" [LintResult UnitNotWellKnown [0]] +> , cmpLint "+2 teaspoons foobar >bar" [LintResult UnitNotWellKnown [0]] +> , cmpLint "+3 cups foobar >bar" [LintResult UnitNotWellKnown [0]] +> , cmpLint "+1 ml foobar >bar" [] +> , cmpLint "+1 cl foobar >bar" [] +> , cmpLint "+1 dl foobar >bar" [] +> , cmpLint "+1 l foobar >bar" [] +> , cmpLint "+2 _ something >bar" [] +> , cmpLint "&1 min [foo] >bar" [] + +The unit is case-sensitive, thus + +> , cmpLint "+1 Mg foobar >bar" [LintResult UnitNotWellKnown [0]] +> , cmpLint "+1 kG foobar >bar" [LintResult UnitNotWellKnown [0]] +> , cmpLint "&1 MIN [foo] >bar" [LintResult UnitNotWellKnown [0]] +> ] + +References +++++++++++ + +All references must be resolved. An `earlier check <#resultsused>`_ ensures +all results and alternatives are referenced at some point. + +> referencesResolved nodes edges = foldl f [] nodes +> where +> f xs (nodeid, Reference _) | null (incomingEdges edges nodeid) = +> LintResult UndefinedReference [nodeid]:xs +> f xs _ = xs + +> testLintRefs = [ +> cmpLint "*foobar >foobar >barbaz" [LintResult CircularLoop [0, 1]] +> , cmpLint "*foobar >foo" [LintResult UndefinedReference [0]] +> ] + +Results and alternatives must not have duplicate names, so collect +their lower-case object names into a ``Map`` and flag those which +reference multiple nodes. + +> uniqueNames nodes _ = M.foldl f [] nameMap +> where +> f xs fnodes | length fnodes > 1 = LintResult DuplicateReferenceName fnodes:xs +> f xs _ = xs +> nameMap = foldl buildMap M.empty nodes +> buildMap m (nodeid, Result qty) = M.insertWith append (getObject qty) [nodeid] m +> buildMap m (nodeid, Alternative qty) = M.insertWith append (getObject qty) [nodeid] m +> buildMap m _ = m +> getObject (Quantity _ _ object) = map toLower object +> append a b = insert (head a) b + +> testUniqueNames = [ +> cmpLint "+a >x +b >y *x *y >foo" [] +> , cmpLint "+a >x +b >x *x >y" [LintResult DuplicateReferenceName [1, 3]] +> , cmpLint "+a >x +b +c |x *x >y" [LintResult DuplicateReferenceName [1, 4]] +> , cmpLint "+a >1 _ foo +a >2 _ FOO +a >3 _ foO *Foo >y" +> [LintResult DuplicateReferenceName [1, 3, 5]] +> ] + +A result must have at least one incoming edge. This is a special case and can +only occur at the beginning of a recipe. + +> resultNonempty nodes edges = foldl f [] nodes +> where +> f xs (nodeid, Result _) | null (incomingEdges edges nodeid) = +> LintResult TooFewChildren [nodeid]:xs +> f xs _ = xs + +> testLintResultNonempty = [ +> cmpLint ">bar *bar >baz" [LintResult TooFewChildren [0]] +> , cmpLint "+A >bar *bar >baz" [] +> , cmpLint "+A >bar >foo *bar *foo >baz" [] +> ] + +Alternatives must have at least two incoming edges since a smaller amount would +make the alternative pointless. + +> twoAlternatives nodes edges = foldl f [] nodes +> where +> f xs (nodeid, Alternative _) | length (incomingEdges edges nodeid) < 2 = +> LintResult TooFewChildren [nodeid]:xs +> f xs _ = xs + +> testLintTwoAlternatives = [ +> cmpLint "+A |foo *foo >bar" [LintResult TooFewChildren [1]] +> , cmpLint "+A +B |foo *foo >bar" [] +> , cmpLint "+A &B |foo *foo >bar" [] +> ] + +.. _reject-loops: + +References cannot loop because, well, you cannot cook something and +use an ingredient you have not made yet. It is possible to branch out +and merge again if an ingredient is split into multiple parts +and added to different outputs. + +> circularLoops nodes edges = map (LintResult CircularLoop) circles +> where +> allReferences = foldl referenceNodes [] nodes +> referenceNodes xs (nodeid, Reference _) = nodeid:xs +> referenceNodes xs _ = xs +> circles = filter (not . null) $ map (visitIncoming [] . singleton) allReferences +> singleton x = [x] +> visitIncoming _ [] = [] +> visitIncoming visited next = case length (intersect visited nextNext) of +> 0 -> visitIncoming nextVisited nextNext +> _ -> nextVisited +> where +> nextVisited = visited ++ next +> nextNext = map fst $ concat $ map (incomingNodes nodes edges) next + +> testLintCircularLoops = [ +> cmpLint "*y >x *x >y >foobar" +> [LintResult CircularLoop [0, 3, 2, 1] , LintResult CircularLoop [2, 1, 0, 3]] +> , cmpLint "*z >x *x >y *y >z *z >foobar" [ +> LintResult CircularLoop [0, 5, 4, 3, 2, 1] +> , LintResult CircularLoop [2, 1, 0, 5, 4, 3] +> , LintResult CircularLoop [4, 3, 2, 1, 0, 5] +> , LintResult CircularLoop [6, 5, 4, 3, 2, 1, 0] +> ] +> , cmpLint "+a >foobar *1/2 _ foobar >x *1/2 _ foobar >y *x *y >final" [] +> , cmpLint "+a >foobar *1/2 _ foobar >x *x *1/2 _ foobar >final" [] +> ] + +Ranges +++++++ + +The first amount of a range ratio must be strictly smaller than the second. +This limitation is not enforced for ranges containing strings. + +> rangeFromLargerThanTo nodes _ = foldl f [] nodes +> where +> f xs (nodeid, Ingredient q) | not $ rangeOk q = +> LintResult RangeFromLargerThanTo [nodeid]:xs +> f xs (nodeid, Reference q) | not $ rangeOk q = +> LintResult RangeFromLargerThanTo [nodeid]:xs +> f xs _ = xs +> rangeOk (Quantity (Range (AmountRatio a) (AmountRatio b)) _ _) = a < b +> rangeOk _ = True + +> testRangeFromLargerThanTo = [ +> cmpLint "+2-3 l water >bar" [] +> , cmpLint "+3-2 l water >bar" [LintResult RangeFromLargerThanTo [0]] +> , cmpLint "+2/3-1/3 l water >bar" [LintResult RangeFromLargerThanTo [0]] +> , cmpLint "+some-many _ eggs >bar" [] +> , cmpLint "+1-\"a few\" _ eggs >bar" [] +> ] + +Appendix +++++++++ + +> data LintResult = LintResult LintStatus [NodeId] deriving (Show, Eq, Ord) +> data LintStatus = +> NoRootNode +> | NonResultRootNode +> | MoreThanOneRootNode +> | UndefinedReference +> | DuplicateReferenceName +> | CircularLoop +> | TooFewChildren +> | TimeIsATool +> | TimeAnnotatesAction +> | UnitNotWellKnown +> | InvalidNode +> | RangeFromLargerThanTo +> | NoMetadata +> | UnknownMetadataKey +> deriving (Show, Eq, Ord) + +Every lint test checks a single aspect of the graph. + +> lint nodes edges = concatMap (\f -> f nodes edges) lintTests + +> lintTests = [ +> rootIsResult +> , referencesResolved +> , uniqueNames +> , circularLoops +> , resultNonempty +> , twoAlternatives +> , timeIsATool +> , timeAnnotatesAction +> , wellKnownUnit +> , lintMetadata +> , rangeFromLargerThanTo +> ] + +> withGraph doc f = f nodes edges +> where +> (Right op) = (head . extract . snd . unzip) <$> parse ("%pesto " ++ doc) +> nodes = zip [firstNodeId..] op +> edges = toGraph nodes ++ resolveReferences nodes + +> cmpLint doc expect = withGraph doc (\nodes edges -> doc ~: sort (lint nodes edges) ~?= sort expect) + + +> data Metadata = MetaQty Quantity | MetaStr String deriving (Show, Eq) + +> cmpLintMeta doc expectLint expectMeta = withGraph doc (\nodes edges -> doc ~: [ +> sort (lint nodes edges) ~?= sort expectLint +> , extractMetadata nodes edges ~?= expectMeta +> ]) +> strQuantity = Quantity (Exact (AmountStr "")) "" + +> test = [ +> testConnectivity +> , testMetadata +> , testLintRefs +> , testUniqueNames +> , testLintCircularLoops +> , testLintQuantity +> , testLintWellKnownUnit +> , testTimeAnnotatesAction +> , testLintTwoAlternatives +> , testLintResultNonempty +> , testRangeFromLargerThanTo +> ] + diff --git a/src/lib/Codec/Pesto/Parse.lhs b/src/lib/Codec/Pesto/Parse.lhs new file mode 100644 index 0000000..762fff4 --- /dev/null +++ b/src/lib/Codec/Pesto/Parse.lhs @@ -0,0 +1,412 @@ +.. _language-syntax: + +Language syntax +--------------- + +.. class:: nodoc + +> module Codec.Pesto.Parse ( +> parse +> , test +> , Instruction(..) +> , Quantity(..) +> , Unit +> , Object +> , Approximately(..) +> , Amount(..) +> , isResult +> , isReference +> , isAlternative +> , isAnnotation +> , isAction +> , isDirective +> , isUnknown +> , spaces1 +> , notspace +> ) where +> import Data.Char (isSpace) +> import Data.Ratio ((%)) +> import Text.Parsec hiding (parse) +> import Text.ParserCombinators.Parsec.Pos (newPos) +> import Text.ParserCombinators.Parsec.Error (newErrorUnknown) +> import Test.HUnit hiding (test) +> +> import Codec.Pesto.Serialize (serialize) + +Pesto parses `UTF-8 <https://tools.ietf.org/html/rfc3629>`_ encoded input data +consisting of space-delimited token. Every character within the Unicode +whitespace class is considered a space. + +.. _spaces1: + +> stream = ((,) <$> getPosition <*> instruction) `sepEndBy` spaces1 +> <?> "stream" +> spaces1 = many1 space + +The following instructions are supported: + +> data Instruction = +> Annotation String +> | Ingredient Quantity +> | Tool Quantity +> | Action String +> | Reference Quantity +> | Result Quantity +> | Alternative Quantity +> | Directive String +> | Unknown String +> deriving (Show, Eq) +> +> instruction = +> try annotation +> <|> try ingredient +> <|> try tool +> <|> try action +> <|> try result +> <|> try alternative +> <|> try reference +> <|> try directive +> <|> try unknown +> <?> "instruction" + +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 :: Char -> Char -> Parsec String () String +> betweenEscaped start end = +> char start +> *> many (try (char '\\' *> char end) <|> satisfy (/= end)) +> <* char end + +Annotations and actions both are of this kind: + +> annotation = Annotation <$> betweenEscaped '(' ')' +> action = Action <$> betweenEscaped '[' ']' + +Here are examples for both: + +> testOpterm = [cmpInstruction "(skinless\nboneless)" (Right (Annotation "skinless\nboneless")) +> , cmpInstruction "[stir together]" (Right (Action "stir together")) +> , 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 a ``Quantity``. + +> oparg :: Char -> Parsec String () Instruction -> Parsec String () Instruction +> oparg ident cont = char ident *> spaces *> cont +> +> ingredient = oparg '+' (Ingredient <$> quantity) +> tool = oparg '&' (Tool <$> quantity) +> result = oparg '>' (Result <$> quantity) +> alternative = oparg '|' (Alternative <$> quantity) +> reference = oparg '*' (Reference <$> quantity) + +Additionally, there are two special instructions. Directives are similar to the +previous instructions but consume a quoted string (``qstr``). + +> directive = oparg '%' (Directive <$> qstr) + +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 messages that provide additional aid to the user, who can then fix +the problem. + +> unknown = Unknown <$> many1 notspace + +Below are examples for these instructions: + +> testOparg = [ +> cmpInstruction "+100 g flour" +> (Right (Ingredient (Quantity (Exact (AmountRatio (100%1))) "g" "flour"))) +> , cmpInstruction "&oven" +> (Right (Tool (strQuantity "oven"))) +> , cmpInstruction ">dough" (Right (Result (strQuantity "dough"))) +> , cmpInstruction "|trimmings" (Right (Alternative (strQuantity "trimmings"))) +> , cmpInstruction "*fish" +> (Right (Reference (strQuantity "fish"))) +> , cmpInstruction3 "% invalid" (Right (Directive "invalid")) "%invalid" +> , cmpInstruction3 "* \t\n 1 _ cheese" +> (Right (Reference (Quantity (Exact (AmountRatio (1%1))) "" "cheese"))) +> "*1 _ cheese" +> , cmpInstruction3 "!invalid" (Right (Unknown "!invalid")) "!invalid" +> ] + +Qstr +++++ + +Before introducing quantities we need to have a look at qstr, which is used by +them. A qstr, short for quoted string, can be a string enclosed in double +quotes, a single word or the underscore character that represents the +empty string. + +> qstr = try (betweenEscaped '"' '"') +> <|> word +> <|> char '_' *> return "" + +A word always starts with a letter, followed by any number of non-space +characters. + +> word = (:) <$> 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. + +> testQstr = [ +> cmpQstr3 "\"\"" (Right "") "_" +> , cmpQstr "_" (Right "") +> , cmpQstr "" parseError + +Any Unicode character with a General_Category major class L (i.e., a letter, see +`Unicode standard section 4.5 +<http://www.unicode.org/versions/Unicode7.0.0/ch04.pdf>`_ for example) is +accepted as first character of a word. That includes german umlauts as well as +greek or arabic script. Numbers, separators, punctuation, and others are not +permitted. + +> , cmpQstr "water" (Right "water") +> , cmpQstr "Äpfel" (Right "Äpfel") +> , cmpQstr "τυρί" (Right "τυρί") +> , cmpQstr "جبن" (Right "جبن") +> , cmpQstr "1sugar" parseError +> , cmpQstr "+milk" parseError +> , cmpQstr "∀onion" parseError + +The remaining letters of a word can be any character, including symbols, +numbers, … + +> , cmpQstr "rump-roast" (Right "rump-roast") +> , cmpQstr "v1negar" (Right "v1negar") +> , cmpQstr "mush\"rooms" (Right "mush\"rooms") + +…but not spaces. + +> , cmpQstr " tomatoes" parseError +> , cmpQstr "tomatoes " parseError +> , cmpQstr "lemon juice" parseError +> , cmpQstr "sour\tcream" parseError +> , cmpQstr "white\nwine" parseError + +If a string contains spaces or starts with a special character, it must be +enclosed in double quotes. + +> , cmpQstr3 "\"salt\"" (Right "salt") "salt" +> , cmpQstr "\"+milk\"" (Right "+milk") +> , cmpQstr "\"soy sauce\"" (Right "soy sauce") +> , cmpQstr "\"1sugar\"" (Right "1sugar") +> , cmpQstr "\"chicken\tbreast\nmeat\"" (Right "chicken\tbreast\nmeat") + +Doublequotes within a string can be quoted by prepending a backslash. However, +the usual escape codes like \\n, \\t, … will *not* be expanded. + +> , cmpQstr "\"vine\"gar\"" parseError +> , cmpQstr3 "\"vine\\\"gar\"" (Right "vine\"gar") "vine\"gar" +> , cmpQstr "\"oli\\ve oil\"" (Right "oli\\ve oil") +> , cmpQstr "\"oli\\\\\"ve oil\"" (Right "oli\\\"ve oil") +> , cmpQstr3 "\"sal\\tmon\"" (Right "sal\\tmon") "sal\\tmon" +> ] + +Quantity +++++++++ + +A ``Quantity`` is a triple of ``Approximately``, ``Unit`` and ``Object`` as parameter. + +> data Quantity = Quantity Approximately Unit Object deriving (Show, Eq) + +The syntactic construct is overloaded and accepts one to three +arguments. If just one is given, it is assumed to be the ``Object`` +and ``Approximately`` and ``Unit`` are empty. Two arguments set +``Approximately`` and ``Unit``, which is convenient when the unit implies +the object (minutes usually refer to the object time, for example). + +> quantity = try quantityA <|> quantityB + +> quantityA = Quantity +> <$> approximately +> <* spaces1 +> <*> unit +> <*> (try (spaces1 *> object) <|> return "") + +> quantityB = Quantity +> <$> return (Exact (AmountStr "")) +> <*> return "" +> <*> object + +> testQuantityOverloaded = [ +> cmpQuantity "oven" (exactQuantity (AmountStr "") "" "oven") +> , cmpQuantity "10 min" (exactQuantity (AmountRatio (10%1)) "min" "") +> , cmpQuantity "100 g flour" (exactQuantity (AmountRatio (100%1)) "g" "flour") + +The first two are equivalent to + +> , cmpQuantity3 "_ _ oven" (exactQuantity (AmountStr "") "" "oven") "oven" +> , cmpQuantity3 "10 min _" (exactQuantity (AmountRatio (10%1)) "min" "") "10 min" + +Missing units must not be omitted. The version with underscore should be preferred. + +> , cmpQuantity3 "1 \"\" meal" (exactQuantity (AmountRatio (1%1)) "" "meal") "1 _ meal" +> , cmpQuantity "1 _ meal" (exactQuantity (AmountRatio (1%1)) "" "meal") +> ] + +Units and objects are just strings. However, units should be limited to +`well-known metric units <#well-known-units>`_. + +> type Unit = String +> unit = qstr +> +> type Object = String +> object = qstr + +``Approximately`` is a wrapper for ranges, that is, two amounts separated by a dash, +approximate amounts, prepended with a tilde, and exact amounts without a modifier. + +> data Approximately = +> Range Amount Amount +> | Approx Amount +> | Exact Amount +> deriving (Show, Eq) +> +> approximately = try range <|> try approx <|> exact +> range = Range <$> amount <*> (char '-' *> amount) +> approx = Approx <$> (char '~' *> amount) +> exact = Exact <$> amount + +> testQuantityApprox = [ +> cmpQuantity "1-2 _ bananas" (Right (Quantity (Range (AmountRatio (1%1)) (AmountRatio (2%1))) "" "bananas")) +> , cmpQuantity "1 - 2 _ bananas" parseError +> , cmpQuantity "1- 2 _ bananas" parseError +> , cmpQuantity "1 -2 _ bananas" parseError +> , cmpQuantity "~2 _ bananas" (Right (Quantity (Approx (AmountRatio (2%1))) "" "bananas")) +> , cmpQuantity "~ 2 _ bananas" parseError +> ] + +Amounts are limited to rational numbers and strings. There are no real numbers +by design, and implementations should avoid representing rational numbers as +floating point numbers. They are not required and introduce ugly corner cases when +rounding while converting units, for example. + +> data Amount = +> AmountRatio Rational +> | AmountStr String +> deriving (Show, Eq) +> +> amount = try ratio <|> AmountStr <$> qstr + +> testQuantityAmount = [ +> cmpQuantity "some _ pepper" (exactQuantity (AmountStr "some") "" "pepper") +> , cmpQuantity3 "\"some\"-\"a few\" _ bananas" (Right (Quantity (Range (AmountStr "some") (AmountStr "a few")) "" "bananas")) "some-\"a few\" _ bananas" +> , cmpQuantity "~\"the stars in your eyes\" _ bananas" (Right (Quantity (Approx (AmountStr "the stars in your eyes")) "" "bananas")) +> ] + +Rational numbers can be an integral, numerator, and denominator, each separated +by a forward slash, just the numerator and denominator, again separated by a +forward slash, or just a numerator with the default denominator 1 (i.e., ordinary +integral number). + +> ratio = let toRatio i num denom = AmountRatio ((i*denom+num)%denom) in +> try (toRatio <$> int <*> (char '/' *> int) <*> (char '/' *> int)) +> <|> try (toRatio <$> return 0 <*> int <*> (char '/' *> int)) +> <|> try (toRatio <$> return 0 <*> int <*> return 1) + +The following representations are all equal with the first one being +the preferred one: + +> testQuantityRatio = [ +> cmpQuantity "3 _ bananas" (exactQuantity (AmountRatio (3%1)) "" "bananas") +> , cmpQuantity3 "3/1 _ bananas" (exactQuantity (AmountRatio (3%1)) "" "bananas") +> "3 _ bananas" +> , cmpQuantity3 "3/0/1 _ bananas" (exactQuantity (AmountRatio (3%1)) "" "bananas") +> "3 _ bananas" + +Two numbers are numerator and denominator: + +> , cmpQuantity "3/5 _ bananas" (exactQuantity (AmountRatio (3%5)) "" "bananas") + +Three numbers add an integral part: + +> , cmpQuantity "3/5/7 _ bananas" (exactQuantity (AmountRatio ((3*7+5)%7)) "" "bananas") +> , cmpQuantity3 "10/3 _ bananas" (exactQuantity (AmountRatio (10%3)) "" "bananas") +> "3/1/3 _ bananas" + +Rational numbers can be used in ranges and mixed with strings too. + +> , cmpQuantity "1-\"a few\" _ bananas" (Right (Quantity +> (Range (AmountRatio (1%1)) (AmountStr "a few")) "" "bananas")) +> , cmpQuantity "1/1/2-2 _ bananas" (Right (Quantity +> (Range (AmountRatio (3%2)) (AmountRatio (4%2))) "" "bananas")) +> , cmpQuantity "~1/1/2 _ bananas" (Right (Quantity +> (Approx (AmountRatio (3%2))) "" "bananas")) +> ] + +Appendix +++++++++ + +Parser main entry point. + +> parse = runParser stream () "" +> int = read <$> many1 digit + +Test helpers: + +> isLeft (Left _) = True +> isLeft _ = False + +A generic parser error: + +> parseError = Left (newErrorUnknown (newPos "" 0 0)) + +Compare output of parser ``f`` for string ``str`` with ``expected``. The +expected result can be a parser error, which matches any actual parse error +(first case). + +> cmpParser f str (Left _) = TestCase $ assertBool str $ isLeft $ runParser (f <* eof) () "" str +> cmpParser f str expected = str ~: runParser (f <* eof) () "" str ~?= expected + +> cmpParseSerialize f str expectp@(Left _) _ = [cmpParser f str expectp] +> cmpParseSerialize f str expectp@(Right expectpval) expects = [ +> cmpParser f str expectp +> , serialize expectpval ~?= expects] + +Wrap qstr test in AmountStr to aid serialization test + +> cmpQstr input expectp = cmpQstr3 input expectp input +> cmpQstr3 input (Left expect) _ = [cmpParser (AmountStr <$> qstr) input (Left expect)] +> cmpQstr3 input (Right expect) expects = cmpParseSerialize (AmountStr <$> qstr) input (Right (AmountStr expect)) expects + +> cmpQuantity a b = cmpQuantity3 a b a +> cmpQuantity3 = cmpParseSerialize quantity + +> cmpInstruction a b = cmpInstruction3 a b a +> cmpInstruction3 = cmpParseSerialize instruction + +> exactQuantity a b c = Right (Quantity (Exact a) b c) +> strQuantity = Quantity (Exact (AmountStr "")) "" + +> test = [ +> "quantity" ~: testQuantityOverloaded +> ++ testQuantityApprox +> ++ testQuantityAmount +> ++ testQuantityRatio +> , "qstr" ~: testQstr +> , "oparg" ~: testOparg +> , "opterm" ~: testOpterm +> ] + +> isResult (Result _) = True +> isResult _ = False +> isReference (Reference _) = True +> isReference _ = False +> isAlternative (Alternative _) = True +> isAlternative _ = False +> isAnnotation (Annotation _) = True +> isAnnotation _ = False +> isAction (Action _) = True +> isAction _ = False +> isDirective (Directive _) = True +> isDirective _ = False +> isUnknown (Unknown _) = True +> isUnknown _ = False + diff --git a/src/lib/Codec/Pesto/Parse.lhs-boot b/src/lib/Codec/Pesto/Parse.lhs-boot new file mode 100644 index 0000000..9096ad7 --- /dev/null +++ b/src/lib/Codec/Pesto/Parse.lhs-boot @@ -0,0 +1,22 @@ +> module Codec.Pesto.Parse where + +> data Instruction = +> Annotation String +> | Ingredient Quantity +> | Tool Quantity +> | Action String +> | Reference Quantity +> | Result Quantity +> | Alternative Quantity +> | Directive String +> | Unknown String +> data Quantity = Quantity Approximately Unit Object +> type Unit = String +> type Object = String +> data Approximately = +> Range Amount Amount +> | Approx Amount +> | Exact Amount +> data Amount = +> AmountRatio Rational +> | AmountStr String diff --git a/src/lib/Codec/Pesto/Serialize.lhs b/src/lib/Codec/Pesto/Serialize.lhs new file mode 100644 index 0000000..17a0fcc --- /dev/null +++ b/src/lib/Codec/Pesto/Serialize.lhs @@ -0,0 +1,66 @@ +Serializing +----------- + +.. class:: nodoc + +> module Codec.Pesto.Serialize (serialize) where +> import Data.Char (isSpace, isLetter) +> import Data.Ratio (numerator, denominator) +> +> import {-# SOURCE #-} Codec.Pesto.Parse + +Serialization turns a linear list of instructions back into a human +representation. + +> class Serializeable a where +> serialize :: a -> String +> +> instance Serializeable a => Serializeable [a] where +> serialize ops = unlines $ map serialize ops + +> instance Serializeable Instruction where +> serialize (Annotation s) = quote '(' ')' s +> serialize (Ingredient q) = '+':serialize q +> serialize (Tool q) = '&':serialize q +> serialize (Action s) = quote '[' ']' s +> serialize (Reference q) = '*':serialize q +> serialize (Result q) = '>':serialize q +> serialize (Alternative q) = '|':serialize q +> serialize (Directive s) = '%':serializeQstr s +> serialize (Unknown s) = s + +> instance Serializeable Quantity where +> serialize (Quantity a b "") = serialize a ++ " " ++ serializeQstr b +> serialize (Quantity (Exact (AmountStr "")) "" c) = serializeQstr c +> serialize (Quantity a "" c) = serialize a ++ " _ " ++ serializeQstr c +> serialize (Quantity a b c) = serialize a ++ " " ++ serializeQstr b ++ " " ++ serializeQstr c + +> instance Serializeable Approximately where +> serialize (Range a b) = serialize a ++ "-" ++ serialize b +> serialize (Approx a) = '~':serialize a +> serialize (Exact a) = serialize a + +There are two special cases here, both for aesthetic reasons: + +1) If the denominator is one we can just skip printing it, because + :math:`\frac{2}{1} = 2` and +2) if the numerator is larger than the denominator use mixed fraction notation, + because :math:`\frac{7}{2} = 3+\frac{1}{2}` + +> instance Serializeable Amount where +> serialize (AmountRatio a) | denominator a == 1 = show (numerator a) +> serialize (AmountRatio a) | numerator a > denominator a = +> show full ++ "/" ++ show num ++ "/" ++ show denom +> where +> full = numerator a `div` denom +> num = numerator a - full * denom +> denom = denominator a +> serialize (AmountRatio a) = show (numerator a) ++ "/" ++ show (denominator a) +> serialize (AmountStr s) = serializeQstr s + +> serializeQstr "" = "_" +> serializeQstr s | (not . isLetter . head) s || hasSpaces s = quote '"' '"' s +> serializeQstr s = s +> hasSpaces = any isSpace +> quote start end s = [start] ++ concatMap (\c -> if c == end then ['\\', end] else [c]) s ++ [end] + |