In Keller's Learn to Read Latin:
The conjunction dum, sometimes strengthened by the adverb modo, "only", may introduce a subordinate clause stating a provision under which the event of the main clause can occur. Such a clause is called a proviso clause.
In a conditional sentence, the conditional clause
states the condition that must occur in order for the main clause to occur.
and is introduced by si or nisi.
My questions are:
What are the differences between conditional and proviso clauses? How different are they in terms of logic?
Can a conjunction that introduces one be used for introducing the other?
Thanks.