Passing two or more files on the command line breaks

[Ducasse]

At least we tested with two slides and they cannot be handled because we have a problem in

CollectionIsEmpty: a Stack() is empty
Stack(Collection)>>errorEmptyCollection
Stack(Collection)>>emptyCheck
Stack(LinkedList)>>removeFirst
Stack>>pop
PRSlideTransformer(PRNodeTransformer)>>replace:
PRSlideTransformer(PRNodeTransformer)>>delete
PRSlideTransformer>>add:toCurrentEnvironmentOr:
PRSlideTransformer>>visitDocumentGroup:
PRSlideTransformer(PRVisitor)>>visitDocument:
PRDocument>>accept:
PRDocument(Object)>>acceptDecorated:
PRSlideTransformer(PRVisitor)>>visit:
PRSlideTransformer(PRVisitor)>>start:
PRSlideTransformer(PRNodeTransformer)>>start:
PRSlideTransformer>>start:
[ :accum :each | each start: accum ] in PRAbstractOutputDocument>>transformDocument: in Block: [ :accum :each | each start: accum ]
[:each | nextValue := binaryBlock value: nextValue value: each] in Set(Collection)>>inject:into: in Block: [:each | nextValue := binaryBlock value: nextValue...etc...
Set>>do:
Set(Collection)>>inject:into:
PRPDFDocument(PRAbstractOutputDocument)>>transformDocument:
PRDocument>>transformDocumentFor:
PRPDFDocument(PRAbstractOutputDocument)>>buildOn: