rejoin using mold

rejoin*.red

rejoin*: func ["Reduces and joins a block of values." 
    block [block!] "Values to reduce and join"
][
    if empty? block: reduce block [return block] 
    append either (series? first block) [copy first block] [
        mold first block
] next block]

some_word: "foo:"
word: to-word "some_word"
lit-word: to-lit-word "some_lit-word"

path: [to[something 42]]
path1: to-path [path to something]
lit-path: to-lit-path [lit path to something]
string: "str"
tag: <tag>
file: %file
bl: [a b c]

  probe rejoin* [
        word
        ":foo:"
    ]
"some_word:foo:"
; "some_word:foo:"
  probe rejoin* [
        'word
        ":foo:"
    ]
"word:foo:"
; "word:foo:"
  probe rejoin* [
        lit-word
        ":foo:"
    ]
"'some_lit-word:foo:"
; "'some_lit-word:foo:"
  probe rejoin* [
        lit-word
        ":foo:"
    ]
"'some_lit-word:foo:"
; "'some_lit-word:foo:"
  probe rejoin* [
        path1
        ":foo:"
    ]
path/to/something/":foo:"
; path/to/something/":foo:"
  probe rejoin* [
        lit-path
        ":foo:"
    ]
'lit/path/to/something/":foo:"
; 'lit/path/to/something/":foo:"
  probe rejoin* [
        string
        ":foo:"
    ]
"str:foo:"
; "str:foo:"
  probe rejoin* [
        tag
        ":foo:"
    ]
<tag:foo:>
; <tag:foo:>
  probe rejoin* [
        file
        ":foo:"
    ]
%file:foo:
; %file:foo:
  probe rejoin* [
        bl
        ":foo:"
    ]
[a b c ":foo:"]
; [a b c ":foo:"]

  rejoin* [#foo 3]
; "#foo3"