String -> Icon works

README.md

@@ -15,23 +15,23 @@ Haskell drakon renderer.
 Proposed input syntax to be converted to diagram images:
 
 ```
-icon "start" as start
-icon "action 1" as action1
-icon "end" as end
+start t "title - description"
+action a1 "action - description"
+end e "end - description"
 
-start > action1
-action1 > end
+t > a1
+a1 > e
 ```
 
-This would render something like:
+This would render something like the following mermaid:
 
 ```mermaid
 stateDiagram-v2
-state "start" as start
-state "action 1" as action1
-state "end" as end
+state "title - description" as title
+state "action - description" as action1
+state "end - description" as end
 
-start --> action1
+title --> action1
 action1 --> end
 ```
 

app/Icon.hs

@@ -0,0 +1,16 @@
+module Icon where
+
+import qualified GHC.Utils.Outputable
+
+data IconType = Title | End | Action | Question
+
+instance Show IconType where
+    show Title = "Title"
+    show End = "End"
+    show Action = "Action"
+    show Question = "Question"
+
+data Icon = Icon { iconText :: String, iconType :: IconType }
+
+instance GHC.Utils.Outputable.Outputable Icon where
+    ppr Icon { iconText = x, iconType = y } = GHC.Utils.Outputable.text $ show y ++ ": " ++ x

app/Main.hs

@@ -1,8 +1,13 @@
 module Main where
 
+import qualified GHC.Utils.Outputable
+import qualified GHC.Utils.Ppr
+
 import qualified Parser
 
+import qualified System.IO
+
 main ::
   IO ()
 main = do
-  print $ Parser.parse Parser.iconDefinition "icon \"starticon1\" as start"
+  GHC.Utils.Outputable.printSDocLn GHC.Utils.Outputable.defaultSDocContext GHC.Utils.Ppr.LeftMode System.IO.stdout $ GHC.Utils.Outputable.ppr $ Parser.parse Parser.iconDefinition "title t \"title - description\""

app/Parser.hs

@@ -3,6 +3,9 @@ module Parser where
 import qualified Control.Applicative
 import qualified Data.Char
 
+-- TODO: to qualified
+import Icon
+
 newtype Parser a = P (String -> [(a, String)])
 
 instance Functor Parser where
@@ -52,14 +55,11 @@ sat f = do
   -- but the below also works:
   -- if f x then P (\input -> [(x, input)]) else Control.Applicative.empty
 
-digit :: Parser Char
-digit = sat Data.Char.isDigit
-
-lower :: Parser Char
-lower = sat Data.Char.isLower
-
-alphanum :: Parser Char
-alphanum = sat Data.Char.isAlphaNum
+isAllowedDescriptionCharacter :: Char -> Bool
+isAllowedDescriptionCharacter x =
+  Data.Char.isAlphaNum x
+  || Data.Char.isSpace x
+  || x == '-'
 
 char :: Char -> Parser Char
 char x = sat (== x)
@@ -71,30 +71,28 @@ string (x:xs) = do
   _ <- string xs
   return (x:xs)
 
-identifier' :: Parser String
-identifier' = do
-  x <- lower
-  xs <- Control.Applicative.many alphanum
-  return (x:xs)
+-- 2024-05-23 PJ:
+-- TODO: many but no more than N
+iconIdentifier :: Parser String
+iconIdentifier = do Control.Applicative.many $ sat Data.Char.isAlphaNum
 
-identifier :: Parser String
-identifier = token identifier'
-
-naturalNumber' :: Parser Int
-naturalNumber' = do
-  xs <- Control.Applicative.some digit
-  return (read xs)
-
-naturalNumber :: Parser Int
-naturalNumber = token naturalNumber'
+iconDescription :: Parser String
+iconDescription = do
+  _ <- symbol "\""
+  name <- Control.Applicative.many $ sat isAllowedDescriptionCharacter
+  _ <- symbol "\""
+  return name
 
-naturalNumbers :: Parser [Int]
-naturalNumbers = do _ <- symbol "["
-                    x <- naturalNumber
-                    xs <- Control.Applicative.many (do symbol ","
-                                                       naturalNumber)
-                    _ <- symbol "]"
-                    return (x:xs)
+-- 2024-05-23 PJ:
+-- I thought about "many but no more than N"
+-- but in the end convinced myself it won't be needed.
+-- We can always limit the number of spaces using an
+-- input size constant.
+-- Any input larger than that constant will be ignored.
+space :: Parser ()
+space = do
+  _ <- Control.Applicative.many (sat Data.Char.isSpace)
+  return ()
 
 token :: Parser a -> Parser a
 token p = do
@@ -106,28 +104,31 @@ token p = do
 symbol :: String -> Parser String
 symbol xs = token (string xs)
 
-integer :: Parser Int
-integer = do
-  _ <- char '-'
-  n <- naturalNumber
-  return (-n)
+iconDefinition'' :: Parser Icon
+iconDefinition'' =
+    do
+      _ <- symbol "title"
+      identifier <- token iconIdentifier
+      description <- token iconDescription
+      return Icon { iconText = description, iconType = Title}
   Control.Applicative.<|>
-  naturalNumber
-
-space :: Parser ()
-space = do
-  _ <- Control.Applicative.many (sat Data.Char.isSpace)
-  return ()
-
-iconDefinition' :: Parser String
-iconDefinition' = do
-  _ <- symbol "icon"
-  _ <- symbol "\""
-  name <- token identifier
-  _ <- symbol "\""
-  _ <- symbol "as"
-  _ <- symbol "start"
-  return name
-
-iconDefinition :: Parser String
-iconDefinition = token iconDefinition'
+    do
+      _ <- symbol "action"
+      identifier <- token iconIdentifier
+      description <- token iconDescription
+      return Icon { iconText = description, iconType = Action}
+  Control.Applicative.<|>
+    do
+      _ <- symbol "question"
+      identifier <- token iconIdentifier
+      description <- token iconDescription
+      return Icon { iconText = description, iconType = Question}
+  Control.Applicative.<|>
+    do
+      _ <- symbol "end"
+      identifier <- token iconIdentifier
+      description <- token iconDescription
+      return Icon { iconText = description, iconType = End}
+
+iconDefinition :: Parser Icon
+iconDefinition = token iconDefinition''

app/Renderer.hs

@@ -8,23 +8,9 @@ import qualified Diagrams.Backend.SVG.CmdLine
 import qualified Diagrams.Prelude
 
 import qualified GHC.Data.Graph.Directed
-import qualified GHC.Utils.Outputable
-import qualified GHC.Utils.Ppr
 
-import qualified System.IO
-
-data IconType = Title | End | Action | Question
-
-instance Show IconType where
-    show Title = "Title"
-    show End = "End"
-    show Action = "Action"
-    show Question = "Question"
-
-data Icon = Icon { iconText :: String, iconType :: IconType }
-
-instance GHC.Utils.Outputable.Outputable Icon where
-    ppr Icon { iconText = x, iconType = y } = GHC.Utils.Outputable.text $ show y ++ ": " ++ x
+-- TODO: to qualified
+import Icon
 
 -- constructing the graph ->
 

drakon-renderer.cabal

@@ -37,8 +37,8 @@ category:           Development
 build-type:         Simple
 
 -- Extra doc files to be distributed with the package, such as a CHANGELOG or a README.
-extra-doc-files:    CHANGELOG.md,
-                    README.md
+extra-doc-files:    changelog.md,
+                    readme.md
 
 -- Extra source files to be distributed with the package, such as examples, or a tutorial module.
 -- extra-source-files:
@@ -51,7 +51,8 @@ executable drakon-renderer
 
     main-is:            Main.hs
 
-    other-modules:      Parser,
+    other-modules:      Icon,
+                        Parser,
                         Renderer
 
     default-extensions: LambdaCase