Gravity C Example

example.c

#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;
}