| pathList tree dumpTree |
pathList := #('abc\def' 'abc\def\gh' 'abc\def\ij' 'abc\jk\lm' 'de').

tree := Dictionary new.
pathList do: [:path |
    (path subStrings: #($\)) inject: tree into: [:tr :dir |
        tr at: dir ifAbsentPut: [Dictionary new]]].

dumpTree := [:tr :lev |
    tr keys asSortedCollection do: [:key |
        Transcript crtab: lev; show: key.
        (tr at: key) ifNotEmptyDo: [:child |
            dumpTree copy fixTemps value: child value: lev + 1]]].

World findATranscript: nil.
dumpTree copy fixTemps value: tree value: 0

"=>
abc
    def
        gh
        ij
    jk
        lm
de
"