feature: Add 'apply' function

src/main/java/marco/lang/error/TypeError.java

@@ -3,7 +3,7 @@
 import marco.lang.MarcoObject;
 
 public class TypeError extends Error {
-    public TypeError(Class expected, MarcoObject value, String fileName, int line) {
+    public TypeError(Class expected, MarcoObject value, String fileName, Integer line) {
         super(fileName, line, "Expected " + expected.getName() + " but got a " + value.getClass().getName());
     }
 }

src/main/java/marco/lang/functions/functions/apply.java

@@ -0,0 +1,18 @@
+package marco.lang.functions.functions;
+
+import marco.lang.MarcoNativeBlock;
+import marco.lang.MarcoObject;
+import marco.lang.MarcoRunnable;
+import marco.runtime.Cast;
+import marco.runtime.Environment;
+import marco.runtime.ListHelper;
+
+public class apply extends MarcoNativeBlock {
+    @Override
+    public MarcoObject invoke(Environment closure, Environment dynamic) {
+        MarcoRunnable runnable = Cast.toRunnable(closure.lookUp("runnable"), getFileName(), getStartLine());
+        MarcoObject args = closure.lookUp("args");
+
+        return runnable.invoke(dynamic, ListHelper.toJavaList(args));
+    }
+}

src/main/java/marco/runtime/Cast.java

@@ -5,7 +5,7 @@
 import marco.lang.*;
 
 public class Cast {
-    public static MarcoRunnable toRunnable(MarcoObject value, String fileName, int line) {
+    public static MarcoRunnable toRunnable(MarcoObject value, String fileName, Integer line) {
         if (value instanceof MarcoRunnable) {
             return (MarcoRunnable) value;
         } else {

src/main/java/marco/runtime/TopLevelEnvironment.java

@@ -14,6 +14,7 @@
 import marco.lang.functions.booleans._not;
 import marco.lang.functions.control_flow._while;
 import marco.lang.functions.docstrings.doc;
+import marco.lang.functions.functions.apply;
 import marco.lang.functions.functions.function;
 import marco.lang.functions.functions.function_question;
 import marco.lang.functions.hash_maps.hash_map;
@@ -43,6 +44,7 @@ public TopLevelEnvironment(MarcoRuntime runtime) {
     private void loadNativeBindings() {
         def("function", new MarcoFunction(this, Arrays.asList("formal", "body"), new function()));
         def("function?", new MarcoFunction(this, Arrays.asList("v"), new function_question()));
+        def("apply", new MarcoFunction(this, Arrays.asList("runnable", "args"), new apply()));
 
         def("true", MarcoBoolean.TRUE);
         def("false", MarcoBoolean.FALSE);

src/test/groovy/tests/marco/lang/functions/functions/apply.groovy

@@ -0,0 +1,18 @@
+package tests.marco.lang.functions.functions
+
+import helpers.MarcoSpecification
+
+class apply extends MarcoSpecification {
+    def "applying a function without arguments"() {
+        given:
+        eval(/ (def :f (function [] { 1 })) /)
+
+        expect:
+        eval(/ (apply f []) /) == eval(/ 1 /)
+    }
+
+    def "applying a function to a list of arguments"() {
+        expect:
+        eval(/ (apply + [1 2]) /) == eval(/ 3 /)
+    }
+}