sylvainkahane
commented
4 years ago I think it is interesting and useful to encode redistributions. It is done for passive and it could be done for impersonal. For passive, the marker is the auxiliary and we have the relations comp:aux@pass and comp:obl@agent. Sometimes the subject is also marked in UD by a relation nsubj:pass and we have a subj@pass in SUD, especially when there is no auxiliary for the passive.
According to this, I find ok to mark the subject in impersonal constructions by subj@impers. In impersonal passive (il a été demandé beaucoup d'attention), we will use both subj@impers and comp:aux@pass.
il arrive deux personnes : arrive -[subj@impers]-> il
We have problem with impersonal passive
perrier54
In the impersonal diathesis, the subject of the sentence is an expletive. The relation between the main verb and the expletive subject is noted expl:subj in UD and subj:expl in SUD. Even if these relations are used in other cases, the conversion between them is not a problem. The subject in the canonical diathesis becomes the direct object in the impersonal diathesis
In SUD, the relation between the verb and the object, which is the subject in the canonical diathesis, is noted comp:obj@agent. In UD, it is noted csubj or nsubj as in the canonical diathesis, because the relation which is considered is deep subject.
When converting from UD to SUD, we must distinguish deep subjects in the impersonal diathesis from canonical subjects. In most cases, we can use the context to do this, but in some cases the expletive subject is far from the main verb, as in the following example.
To facilitate the conversion, I propose to add extension impers to nsubj or csubj for the deep subjects in the impersonal diathesis. In the previous example, this would give: arrivé -[nsubj:impers]-> malheur.
The impersonal diathesis may be combined with the passive diathesis, as in the following example.
The object of "demandé" is "beaucoup". The relation is currently noted comp:obj@pass in SUD and nsubj:pass in UD. I propose to replace nsubj:pass (csubj:pass) by nsubj:impers (csubj:impers) to distinguish this function in the impersonal diathesis of the canonical passive subject and to facilitate the conversion from UD to SUD. The passive voice can be recovered with the passive auxiliary.