The `render()` function executes the specified path as ucode script,
optionally setting a different execution scope for the invoked file,
and captures the produced output in a string.

If the specified path is relative, it is treated as being relative to the
source file currently being executed or the current working directory in
case the interpreter executes code from stdin or a command line argument.

Throws an exception if the given path value is not a string.

Throws an exception if a scope argument is specified and not a valid object.

Throws an exception if the given path could not be found or opened.

Throws an exception if the given file could not be compiled.

Returns a string containing the captured output of the executed file.

-- Testcase --
{%
	let real_printf = printf;

	printf("%.J\n", [
		// include by relative path
		render("files/include.uc"),

		// include by absolute path
		render(TESTFILES_PATH + "/include.uc"),

		// include with overridden scope
		render("files/include.uc", {
			printf: function(...args) {
				real_printf("This is the wrapped printf() getting called!\n");

				return real_printf(...args);
			}
		}),

		// include with isolated scope
		render("files/include.uc", proto({
			printf: function(...args) {
				real_printf("This is the wrapped printf() getting called!\n");

				return real_printf(...args);
			}
		}, {}))
	]);
%}
-- End --

-- File include.uc --
{%
	printf("This is the include file running! Can I access the global env? %s\n",
		REQUIRE_SEARCH_PATH ? "Yes!" : "No.");
%}
-- End --

-- Expect stdout --
[
	"This is the include file running! Can I access the global env? Yes!\n",
	"This is the include file running! Can I access the global env? Yes!\n",
	"This is the wrapped printf() getting called!\nThis is the include file running! Can I access the global env? Yes!\n",
	"This is the wrapped printf() getting called!\nThis is the include file running! Can I access the global env? No.\n"
]
-- End --


An invalid path value triggers an exception.

-- Testcase --
{%
	include(true);
%}
-- End --

-- Expect stderr --
Type error: Passed filename is not a string
In line 2, byte 14:

 `    include(true);`
  Near here ------^


-- End --


An invalid scope value triggers an exception.

-- Testcase --
{%
	include("test", true);
%}
-- End --

-- Expect stderr --
Type error: Passed scope value is not an object
In line 2, byte 22:

 `    include("test", true);`
  Near here --------------^


-- End --


A not found file triggers an exception.

-- Testcase --
{%
	include("files/doesnotexist.uc");
%}
-- End --

-- Expect stderr --
Runtime error: Include file not found
In line 2, byte 33:

 `    include("files/doesnotexist.uc");`
  Near here -------------------------^


-- End --


A compilation error in the file triggers an exception.

-- Testcase --
{%
	try {
		include("files/broken.uc");
	}
	catch (e) {
		// Catch and rethrow exception with modified message to
		// ensure stable test output.
		e.message = replace(e.message,
			/(compile module '.+broken\.uc')/,
			"compile module '.../broken.uc'");

		die(e);
	}
%}
-- End --

-- File broken.uc --
{%
	// Unclosed object to force syntax error
	return {
%}
-- End --

-- Expect stderr --
Unable to compile module '.../broken.uc':
Syntax error: Expecting label
In line 3, byte 11:

 `    return {`
  Near here --^



In line 12, byte 8:

 `        die(e);`
  Near here ---^


-- End --