diff --git a/README.md b/README.md
index e9b2aee..9a42b47 100644
--- a/README.md
+++ b/README.md
@@ -534,17 +534,18 @@ while | yes | Control flow
 
 ### Core functions
 
-Name  | Safe-mode | Example | Example result | Description
------ | --------- | ------- | -------------- | -----------
-debug | no  | `(debug)` | `true` |  Toggle debug output.
-doc   | yes | `(doc +)` | `"Return the sum of all arguments."` | Show the documentation string for a function.
-      | yes | `(doc myfn "Documentation string.")` | `"Documentation string."` | Set the documentation string for a function.
-exit  | no  | `(exit 1)` | | Terminate the script with given exit code using [exit](https://www.php.net/manual/en/function.exit.php).
-print | no  | `(print "hello world")` | `hello world` | Print expression on the screen. Give optional second argument as `true` to show strings in readable format. Print returns null (shown in REPL).
-pstr  | yes | `(pstr {"a":"b"})` | `"{\"a\":\"b\"}"` | Print expression to string.
-read  | yes | `(read "(+ 1 2 3)")` | `(+ 1 2 3)` | Read a string as code and return the expression.
-sleep | no  | `(sleep 2000)` | `null` | Sleep for the given period given in milliseconds using [usleep](https://www.php.net/manual/en/function.usleep).
-throw | yes | `(throw "invalid value")` | `error: "invalid value"` | Throw an exception. The given value is passed to catch. See the section Exceptions.
+Name   | Safe-mode | Example | Example result | Description
+------ | --------- | ------- | -------------- | -----------
+debug  | no  | `(debug)` | `true` |  Toggle debug output.
+doc    | yes | `(doc +)` | `"Return the sum of all arguments."` | Show the documentation string for a function.
+       | yes | `(doc myfn "Documentation string.")` | `"Documentation string."` | Set the documentation string for a function.
+exit   | no  | `(exit 1)` | | Terminate the script with given exit code using [exit](https://www.php.net/manual/en/function.exit.php).
+print  | no  | `(print "hello world")` | `hello world` | Print expression on the screen.
+printr | no  | `(printr "hello world")` | `"hello world"` | Print expression on the screen in readable format.
+prints | yes | `(prints "hello world")` | `"\"hello world\""` | Print expression to string in readable format.
+read   | yes | `(read "(+ 1 2 3)")` | `(+ 1 2 3)` | Read a string as code and return the expression.
+sleep  | no  | `(sleep 2000)` | `null` | Sleep for the given period given in milliseconds using [usleep](https://www.php.net/manual/en/function.usleep).
+throw  | yes | `(throw "invalid value")` | `error: "invalid value"` | Throw an exception. The given value is passed to catch. See the section Exceptions.
 
 ### Collection functions
 
diff --git a/mad/calc.mad b/mad/calc.mad
index b160704..7a0107b 100644
--- a/mad/calc.mad
+++ b/mad/calc.mad
@@ -15,7 +15,8 @@
 (defn cmdMod (args) (apply % args))
 (defn cmdMul (args) (apply * args))
 (defn cmdSub (args) (apply - args))
-(defn cmdHelp (args) (str "Available commands: " (apply join ", " (keys cmdMap))))
+(defn cmdHelp () (str "Available commands: " (apply join ", " (keys cmdMap))))
+(defn cmdQuit () (exit))
 
 ;; And we define a hash-map for command lookups with minimum number of arguments
 (def cmdMap {
@@ -25,6 +26,7 @@
   "mul": [cmdMul 2]
   "sub": [cmdSub 2]
   "help": [cmdHelp 0]
+  "quit": [cmdQuit 0]
 })
 
 ;; Find the first command which starts with the given name, or null
@@ -38,8 +40,8 @@
 ;; and call it, giving the rest of the words as arguments.
 (defn parseInput (inp)
   (let (words (split " " inp) cname (first words) args (tail words) cmd (findCmd cname))
-    (if (null? cmd) (print "Unknown command, try 'help'.")
-      (if (< (len args) (second cmd)) (print (str "Give at least 2 arguments to " cname "."))
+    (if (null? cmd) "Unknown command, try 'help'."
+      (if (< (len args) (second cmd)) (str "Give at least 2 arguments to " cname ".")
         ((first cmd) args)))))
 
 ;; Define a file for readline and load it
@@ -51,4 +53,4 @@
   (let (inp (readline "[calc] "))
     (readline-add inp)
     (readline-save readlineFile)
-    (print (str "⇒ " (parseInput inp) EOL))))
+    (print "⇒ " (parseInput inp) EOL)))
diff --git a/mad/dump.mad b/mad/dump.mad
index 09116d9..185d8df 100644
--- a/mad/dump.mad
+++ b/mad/dump.mad
@@ -11,8 +11,8 @@
 ;; Return the string for defining the given function
 (defn funcToStr (f name)
   (str (if (macro? f) "(defmacro " "(defn ")
-    name " " (pstr (meta f "args")) " "
-    (pstr (meta f "body")) ")"))
+    name " " (prints (meta f "args")) " "
+    (prints (meta f "body")) ")"))
 
 ;; Write a hash-map of functions into a file
 (defn dumpFuncs (funcs filename)
diff --git a/mad/misc.mad b/mad/misc.mad
index a28211c..6f90b82 100644
--- a/mad/misc.mad
+++ b/mad/misc.mad
@@ -1,2 +1,2 @@
 ;; Measure how long it takes to execute f
-(defn timer (f) (let (st (mtime)) (f) (- (mtime) st)))
+(defn timeFn (f) (let (st (mtime)) (f) (- (mtime) st)))
diff --git a/src/Evaller.php b/src/Evaller.php
index a1cbe67..c2b6126 100644
--- a/src/Evaller.php
+++ b/src/Evaller.php
@@ -212,8 +212,8 @@ class Evaller
 
                     return $env;
                 } elseif ($symbolName == 'eval') {
-                    if ($astLength == 1) {
-                        return null;
+                    if ($astLength != 2) {
+                        throw new MadLispException("eval requires exactly 1 argument");
                     }
 
                     $ast = $this->eval($astData[1], $env, $depth + 1);
diff --git a/src/Lib/Core.php b/src/Lib/Core.php
index c96964e..1d64c5c 100644
--- a/src/Lib/Core.php
+++ b/src/Lib/Core.php
@@ -69,15 +69,26 @@ class Core implements ILib
         }
 
         if (!$this->safemode) {
-            $env->set('print', new CoreFunc('print', 'Print argument. Give second argument as true to show strings in readable format.', 1, 2,
-                function ($a, bool $readable = false) {
-                    $this->printer->print($a, $readable);
+            $env->set('print', new CoreFunc('print', 'Print arguments.', 0, -1,
+                function (...$args) {
+                    foreach ($args as $a) {
+                        $this->printer->print($a, false);
+                    }
                     return null;
                 }
             ));
         }
 
-        $env->set('pstr', new CoreFunc('pstr', 'Print argument to string.', 1, 1,
+        if (!$this->safemode) {
+            $env->set('printr', new CoreFunc('printr', 'Print argument in readable format.', 1, 1,
+                function ($a) {
+                    $this->printer->print($a, true);
+                    return null;
+                }
+            ));
+        }
+
+        $env->set('prints', new CoreFunc('prints', 'Print argument in readable format to string.', 1, 1,
             function ($a) {
                 return $this->printer->pstr($a, true);
             }