Updated makefile and added example.c

Makefile

@@ -4,13 +4,14 @@ SHARED_DIR = src/shared/
 UTILS_DIR = src/utils/
 OPT_DIR = src/optionals/
 GRAVITY_SRC = src/cli/gravity.c
+EXAMPLE_SRC = examples/example.c
 
 CC ?= gcc
 SRC = $(wildcard $(COMPILER_DIR)*.c) \
-      $(wildcard $(RUNTIME_DIR)/*.c) \
-      $(wildcard $(SHARED_DIR)/*.c) \
-      $(wildcard $(UTILS_DIR)/*.c) \
-      $(wildcard $(OPT_DIR)/*.c)
+      $(wildcard $(RUNTIME_DIR)*.c) \
+      $(wildcard $(SHARED_DIR)*.c) \
+      $(wildcard $(UTILS_DIR)*.c) \
+      $(wildcard $(OPT_DIR)*.c)
 
 INCLUDE = -I$(COMPILER_DIR) -I$(RUNTIME_DIR) -I$(SHARED_DIR) -I$(UTILS_DIR) -I$(OPT_DIR)
 CFLAGS = $(INCLUDE) -std=gnu99 -fgnu89-inline -fPIC -DBUILD_GRAVITY_API
@@ -59,11 +60,14 @@ all: gravity
 
 gravity:	$(OBJ) $(GRAVITY_SRC)
 	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
-
-.PHONY: all clean gravity
+	
+example:	$(OBJ) $(EXAMPLE_SRC)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
 
 lib: gravity
 	$(CC) -shared -o $(LIBTARGET) $(OBJ) $(LDFLAGS)
 
 clean:
-	rm -f $(OBJ) gravity libgravity.so gravity.dll
+	rm -f $(OBJ) gravity example libgravity.so gravity.dll
+	
+.PHONY: all clean gravity example

examples/example.c

@@ -0,0 +1,51 @@
+#include "gravity_compiler.h"
+#include "gravity_macros.h"
+#include "gravity_core.h"
+#include "gravity_vm.h"
+
+#define SOURCE	"func main() {var a = 10; var b=20; return a + b}"
+
+// error reporting callback called by both compiler or VM
+static void report_error (gravity_vm *vm, error_type_t error_type,
+                          const char *description, error_desc_t error_desc, void *xdata) {
+    printf("%s\n", description);
+    exit(0);
+}
+
+int main (void) {
+    // configure a VM delegate
+    gravity_delegate_t delegate = {.error_callback = report_error};
+    
+    // compile Gravity source code into bytecode
+    gravity_compiler_t *compiler = gravity_compiler_create(&delegate);
+    gravity_closure_t *closure = gravity_compiler_run(compiler, SOURCE, strlen(SOURCE), 0, true, true);
+    
+    // sanity check on compiled source
+    if (!closure) {
+        // an error occurred while compiling source code and it has already been reported by the report_error callback
+        gravity_compiler_free(compiler);
+        return 1;
+    }
+    
+    // create a new VM
+    gravity_vm *vm = gravity_vm_new(&delegate);
+    
+    // transfer objects owned by the compiler to the VM (so they can be part of the GC)
+    gravity_compiler_transfer(compiler, vm);
+    
+    // compiler can now be freed
+    gravity_compiler_free(compiler);
+    
+    // run main closure inside Gravity bytecode
+    if (gravity_vm_runmain(vm, closure)) {
+        // print result (INT) 30 in this simple example
+        gravity_value_t result = gravity_vm_result(vm);
+        gravity_value_dump(vm, result, NULL, 0);
+    }
+    
+    // free VM memory and core libraries
+    gravity_vm_free(vm);
+	gravity_core_free();
+    
+    return 0;
+}