Some easy questions from beginer

[Sergey Dolin <dsa-ugur at chel dot surnet dot ru>]

1. What does mean symbol ":" in the guile's variable/function name?

Explain, what i am inetersting to - I've the .c library for simple
text mode UI. I want guile interface to it to get ability to write
something like

(set! screen1
        (ui:screen 
                (ui:label "bla-bla")
                (ui:text "foo")
                (ui:num "1.00")))

(ui:loop screen1)

where ui: - prefix to avoid interfer'n with others ident-s

I see some bad things in that naming convention:
a. It's ambigous for word-completation untl fourth letter
b. too long
c. I'm not shure the symbol ':' is right choice (i'v seen it in ice9)

Can anybody to give me intro in "guile-style"?

The second question is very simply, i think, but....

2. When to use "protect-from-gc"(i've seen it in libguile/*.c)?

Exactly. I've received some smob in my SCM ui_some_func(SCM smob){...} -
Have i to protect the smob from gc right now? What is pointing to
the snob during gsubr calling?

3.While reaing docs, i've stucked on function what is not defined
in "libguile.h". Is where any flavours of guile what can coused it?

thanx

Sergey.