feat: add string? and number? (#1130)

src/Commands.hs

@@ -432,6 +432,18 @@ commandIsSymbol ctx x =
     XObj (Sym _ _) _ _ -> (ctx, Right trueXObj)
     _ -> (ctx, Right falseXObj)
 
+commandIsNumber :: UnaryCommandCallback
+commandIsNumber ctx x =
+  pure $ case x of
+    XObj (Num _ _) _ _ -> (ctx, Right trueXObj)
+    _ -> (ctx, Right falseXObj)
+
+commandIsString :: UnaryCommandCallback
+commandIsString ctx x =
+  pure $ case x of
+    XObj (Str _) _ _ -> (ctx, Right trueXObj)
+    _ -> (ctx, Right falseXObj)
+
 commandArray :: VariadicCommandCallback
 commandArray ctx args =
   pure (ctx, Right (XObj (Arr args) (Just dummyInfo) Nothing))

src/StartingEnv.hs

@@ -247,6 +247,8 @@ dynamicModule =
             f "list?" commandIsList "checks whether the argument is a list." "(list? '()) ; => true",
             f "array?" commandIsArray "checks whether the arguments is an array." "(array? []) ; => true",
             f "symbol?" commandIsSymbol "checks whether the argument is a symbol." "(symbol? 'x) ; => true",
+            f "number?" commandIsNumber "checks whether the argument is a number." "(number? 1) ; => true",
+            f "string?" commandIsString "checks whether the argument is a string." "(string? \"hi\") ; => true",
             f "length" commandLength "returns the length of the argument (must be an array, string or list)." "(length '(1 2 3)) ; => 3",
             f "car" commandCar "gets the head of a list or array." "(car '(1 2 3)) ; => 1",
             f "cdr" commandCdr "gets the tail of a list or array." "(cdr '(1 2 3)) ; => '(2 3)",