You could use include keyword to add another file to current execution when program run.
Ex:
File a.gtc
@sum $a, $b
return $a + $b
@echo “this is file a\n”
File b.gtc
@echo “begin file b\n”
include “a.gtc”
@echo “this is file b\n”
@echo @sum 3, 4
This is equivalent to:
@echo “begin file b\n”
@sum $a, $b
return $a + $b
@echo “this is file a\n”
@echo “this is file b\n”
@echo @sum 3, 4
> begin file b
> this is file a
> this is file b
> 7
About the function
@sum $a, $b
return $a + $b
please see function section