I can't get a straight answer ANYWHERE about this question.
In BASH, you can include a 'partial' script and execute it inline in the rest of your bash script with the following syntax:
#!/usr/bin/bash
. ~/my-partial-include-preamble-script.in.sh
# do stuff here
# .
# .
# .
The question is this: is this syntax in the POSIX standard, and if not, is there some syntax in the standard which accomplishes the same thing? Is there a link anyone can post showing where in the POSIX standard this syntax is defined (if applicable)?