Which grammar rules are applied when でいい is conjugated to nouns?


"ここに名前を書くだけでいいですか？" means "Is it ok to just write [my] name here?"

I'm confused about where でいい comes from.

<http://www.guidetojapanese.org/learn/grammar/must#part5> is about conjugating
ていい /でいい to adjectives and verbs.

I don't know which grammar rules are applied when でいい is conjugated to nouns
as in "ここに名前を書くだけでいいですか？".

Can anyone tell me?




The 「〜でいい」 you see after nouns can be analyzed as follows:

> 「だ」's continuative form + 「いい」

* * *

「だ」's continuative form, 「で」, should not be confused with the 「…で」 you see in
the て-form of verbs (like 「飲んで」), which is actually just a 「て」 that has
undergone a sound change:

> //nomite//  
>  ⇒ //nomte//  
>  ⇒ //nonde//




The option でいい is also available for nominals:

[code]

     (1) それでいい。
         It's ok/enough.
     (2) そのままでいい。
         It's fine that way.
    
[/code]

だけ in 書くだけ is a nominal, but it is not free, rather it must attach to
something, in this case 書く. だけ is a nominal suffix, and it expresses a
limitation, rendered in English as _only_ or _just_. Other limitative nominal
suffixes are ばかり, ぐらい・くらい, ほど, まで, and どころ.

Since だけ is a nominal, the expression でいい can attach to form your example,
(1), (2), or others.

