Is there a way to configure word separator for partial completion style?

[Milan Glacier]

The emacs documentation
(https://www.gnu.org/software/emacs/manual/html_node/emacs/Completion-Styles.html)
suggests that "partial-completion" uses hyphens or spaces as word
separator. Is there a way to use other characters as the word separator?

This is very useful for other languages (say python, C) which usually
uses underscore as the word separator. Say I want to complete `foo_bar`,
then I may just type `f_m` to complete `foo_bar`.

Thanks in advance for your kind help.