input from terminal args

README.md

@@ -15,9 +15,9 @@ Haskell drakon renderer.
 Proposed input syntax to be converted to diagram images:
 
 ```
-start t "title - description"
-action a1 "action - description"
-end e "end - description"
+Title t "title - description"
+Action a1 "action - description"
+End e "end - description"
 
 t > a1
 a1 > e

app/Main.hs

@@ -6,8 +6,23 @@ import qualified GHC.Utils.Ppr
 import qualified Parser
 
 import qualified System.IO
+import qualified System.Environment
+
+inputValidation :: [String] -> (Bool, String)
+inputValidation [] = (False, "no input provided")
+inputValidation [x] = (True, x)
+inputValidation inputList = (False, "only one input argument expected but " ++ show (length inputList) ++ " provided")
 
 main ::
   IO ()
 main = do
-  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\""
+  input <- System.Environment.getArgs :: IO [String]
+
+  case inputValidation input of
+    (True, x) -> do
+      putStrLn ("input: \"" ++ x ++ "\" translates to:")
+      GHC.Utils.Outputable.printSDocLn
+        GHC.Utils.Outputable.defaultSDocContext
+        GHC.Utils.Ppr.LeftMode
+        System.IO.stdout $ GHC.Utils.Outputable.ppr $ Parser.parse Parser.iconDefinition x
+    (False, x) -> putStrLn x

app/Parser.hs

@@ -3,8 +3,7 @@ module Parser where
 import qualified Control.Applicative
 import qualified Data.Char
 
--- TODO: to qualified
-import Icon
+import qualified Icon
 
 newtype Parser a = P (String -> [(a, String)])
 
@@ -52,8 +51,6 @@ sat :: (Char -> Bool) -> Parser Char
 sat f = do
   x <- item
   if f x then return x else Control.Applicative.empty
-  -- but the below also works:
-  -- if f x then P (\input -> [(x, input)]) else Control.Applicative.empty
 
 isAllowedDescriptionCharacter :: Char -> Bool
 isAllowedDescriptionCharacter x =
@@ -72,6 +69,7 @@ string (x:xs) = do
   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
@@ -84,6 +82,7 @@ iconDescription = do
   return name
 
 -- 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
@@ -104,31 +103,31 @@ token p = do
 symbol :: String -> Parser String
 symbol xs = token (string xs)
 
-iconDefinition'' :: Parser Icon
-iconDefinition'' =
+iconDefinition' :: Parser Icon.Icon
+iconDefinition' =
     do
-      _ <- symbol "title"
+      _ <- symbol "Title"
       identifier <- token iconIdentifier
       description <- token iconDescription
-      return Icon { iconText = description, iconType = Title}
+      return Icon.Icon { Icon.iconText = description, Icon.iconType = Icon.Title}
   Control.Applicative.<|>
     do
-      _ <- symbol "action"
+      _ <- symbol "Action"
       identifier <- token iconIdentifier
       description <- token iconDescription
-      return Icon { iconText = description, iconType = Action}
+      return Icon.Icon { Icon.iconText = description, Icon.iconType = Icon.Action}
   Control.Applicative.<|>
     do
-      _ <- symbol "question"
+      _ <- symbol "Question"
       identifier <- token iconIdentifier
       description <- token iconDescription
-      return Icon { iconText = description, iconType = Question}
+      return Icon.Icon { Icon.iconText = description, Icon.iconType = Icon.Question}
   Control.Applicative.<|>
     do
-      _ <- symbol "end"
+      _ <- symbol "End"
       identifier <- token iconIdentifier
       description <- token iconDescription
-      return Icon { iconText = description, iconType = End}
+      return Icon.Icon { Icon.iconText = description, Icon.iconType = Icon.End}
 
-iconDefinition :: Parser Icon
-iconDefinition = token iconDefinition''
+iconDefinition :: Parser Icon.Icon
+iconDefinition = token iconDefinition'

run.sh

@@ -1,2 +1,2 @@
 #!/bin/zsh
-cabal run drakon-renderer -- -o diagram-troubleshooting-on.svg -w 1000
+cabal run drakon-renderer "Title t \"title - description\""