What is the function of と when it's not quoting, or doing exhaustive listing?

Question

Consider these two sentences:

　(1) 母はついてくるようにアリスに合図した (Mother signaled to Alice to follow her)

　(2) 父は手で私に部屋を出ていくようにと合図した。 (Father gestured to me to go out of the room)

And another sentence which I suspect has the same use of と　as (2) but I cannot exactly say what it does:

(3) この本は子供を対象とした本です。(Unnatural: This book is a book that is done in order for children to be targets) (Natural: This is a book for children)

Now I deconstruct the use of AをBとC in (3) to mean "Do verb C to achieve state B in direct object A"

(Question) How would I understand the use of と in (2)? Since (1) does not require と yet has a similar structure involving ように. But XようにY means "to do Y so that X can happen". What happens when と is added to the mix as in (2)?

(Example sentences taken from WWWJDIC)

Answer 1

Francis Drohan's A handbook of Japanese usage has four whole pages on the usages of と, so I don't think a comprehensive answer is appropriate here. But a few key points:

• There are two kinds of と: one is a case particle (格助詞), and another is a conjunctive particle (接続助詞). In both your examples, と is being used as a case particle.

• According to Drohan, there are 7 main uses for the case particle と: Listing, accompaniment, target of comparison, result of change, adverbialisation, quotation, and simile.

• と in your example (2) is being used to denote quotation. ‘Father signalled to me with his hand, “get out of the room.”’

• と in your example (3) is being used to denote the result of change. (In fact, Drohan gives the following example: 学生を対象とする。 It is meant for students.) The construction 〜とする here has the connotation of a decision being made: the target audience was set to be students.

  Drohan gives some other examples of this usage:

  塵も積もれば山となる。 Many a little makes a mickle.

  夜となく昼となく働く。 They work morning, noon and night.

• However, the collocation 〜とする also has other uses, e.g. 学生として ‘as a student’,　なかったとしたら ‘supposing there were none’, etc.

Answer 2

The と in (1, 2) is the same と as used in quoting. It leads a subordinate clause. Unlike predicates like 言う 'say', which can take direct or indirect quotation, predicates like 合図する 'signal' cannot take quotation. It expresses an accompanied message. Without と, it is ambiguous. It may be a purposive clause or a clause expressing the accompanied message.

母はついてくるようにアリスに合図した
'Mother signaled Alice to follow her'
'Mother signaled Alice so that she will follow her'

With と, it is unambiguously a clause expressing the accompanied message.

母はついてくるようにとアリスに合図した
'Mother signaled Alice to follow her'

The と in (3) is completely different. Note that the と in (3) is attached to a noun rather than a clause. In this sentence, the noun is the main predicate. When a noun is a predicate, it takes either に or と.

Nominal predicate

対象に/となる
対象である [Underlyingly にてある]
対象に/とする