feat: project also builds a "repl" executable

3 files changed, 30 insertions, 6 deletions

diff --git a/app/Repl.hs b/app/Repl.hs
new file mode 100644
index 0000000..9f26d78
--- /dev/null
+++ b/app/Repl.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import BizExpr (repl)
+
+main :: IO ()
+main = repl
diff --git a/hs.cabal b/hs.cabal
index 7f3bcf8..9cab28f 100755
--- a/hs.cabal
+++ b/hs.cabal
@@ -24,10 +24,8 @@ build-type:         Simple
 extra-source-files: CHANGELOG.md
 
 library
-    exposed-modules: RestService 
-
-    -- Modules included in this library but not exported.
-    other-modules: BizExpr
+    exposed-modules: RestService,
+                     BizExpr
 
     -- LANGUAGE extensions used by modules in this package.
     -- other-extensions:
@@ -43,6 +41,21 @@ library
     hs-source-dirs:   src
     default-language: Haskell2010
 
+executable repl
+    main-is:          Repl.hs
+
+    -- Modules included in this executable, other than Main.
+    -- other-modules:
+
+    -- LANGUAGE extensions used by modules in this package.
+    -- other-extensions:
+    build-depends:
+        base ^>=4.19.1.0,
+        hs
+
+    hs-source-dirs:   app
+    default-language: Haskell2010
+
 executable hs
     main-is:          Main.hs
 
diff --git a/src/BizExpr.hs b/src/BizExpr.hs
index 1026e47..20a25d1 100755
--- a/src/BizExpr.hs
+++ b/src/BizExpr.hs
@@ -12,10 +12,13 @@ type Context = M.Map L.Text L.Text
 --import Data.Text as T
 
 repl :: IO ()
-repl = getLine >>= putStrLn . maybe "Failed to evaluate expression" show . (eval M.empty :: String -> Maybe Integer) >> repl
+repl = getLine >>= putStrLn . maybe "Failed to evaluate expression" id . (eval M.empty :: String -> Maybe String) >> repl
+
+maybeHead (x:_) = Just x
+maybeHead _ = Nothing
 
 eval :: CoerceTo a => Context -> String -> Maybe a
-eval c x = coerceTo =<< evalAst . head . fst =<< parseLevel c x
+eval c x = coerceTo =<< evalAst =<< maybeHead . fst =<< parseLevel c x
 
 data Value = IntVal Integer | StrVal String | BoolVal Bool | FloatVal Float
   deriving (Show)
@@ -82,6 +85,8 @@ parseLevel c = go "" (Just [])
     go prev (Just l) (',' : next) =
       let l0 = [Val $ newVal c prev]
        in go "" (Just (l ++ l0)) next
+    go prev l (' ' : next) =
+      go "" l next
     go "" (Just l) "" =
       Just (l, "")
     go prev (Just l) "" =