[ racket ] Add library loading (#3049)

CHANGELOG.md

@@ -40,6 +40,12 @@
 * Non-recursive top-level constants are compiled to eagerly evaluated
   constants in Chez Scheme.
 
+#### Racket
+
+* FFI declarations can now specify which `require` to perform, i.e. which
+  library to load before executing the FFI.
+  The syntax is `scheme,racket:my-function,my-library`.
+
 #### Node.js/Browser
 
 * Generated JavaScript files now include a shebang when using the Node.js backend

src/Compiler/Scheme/Racket.idr

@@ -280,6 +280,9 @@ useCC appdir fc ccs args ret
            Just ("scheme,racket", [sfn]) =>
                do let body = schemeCall fc sfn (map fst args) ret
                   pure ("", body)
+           Just ("scheme,racket", [sfn, racketlib]) =>
+               do let body = schemeCall fc sfn (map fst args) ret
+                  pure (fromString $ "(require " ++ racketlib ++ ")", body)
            Just ("scheme", [sfn]) =>
                do let body = schemeCall fc sfn (map fst args) ret
                   pure ("", body)

tests/Main.idr

@@ -339,6 +339,7 @@ racketTests = MkTestPool "Racket backend" [] (Just Racket)
     , "conditions005"
 --    , "conditions006"
 --    , "conditions007"
+    , "ffi001"
     ]
 
 nodeTests : TestPool

tests/racket/ffi001/RacketLib.idr

@@ -0,0 +1,8 @@
+%foreign "scheme,racket:(lambda (x) (if (port-number? x) 1 0)),racket/tcp"
+isPortNumber : Int -> Bool
+
+main : IO ()
+main = do
+  putStrLn $ "0 is port: " ++ show (isPortNumber 0)
+  putStrLn $ "1 is port: " ++ show (isPortNumber 1)
+  putStrLn $ "2 is port: " ++ show (isPortNumber 2)

tests/racket/ffi001/expected

@@ -0,0 +1,3 @@
+0 is port: False
+1 is port: True
+2 is port: True

tests/racket/ffi001/run

@@ -0,0 +1 @@
+$1 --no-banner --no-color --console-width 0 --cg racket RacketLib.idr --exec main