fun to make and fun to eat
“These cookies are fun to make and especially fun to eat.” (source)
Semantically, these cookies is both to-infinitves’ object; and to-infinitves seems to be the semantic subject of both funs, as is in the sentence of "It's fun to take a walk". Is this right understanding? Or do the to-infinitves become semantic object of both funs?
Solution 1:
These cookies are fun to make and especially fun to eat.
As the OP suggests, this is a Conjunction Reduction of
- These cookies are fun to make and these cookies are especially fun to eat.
Let's just take one of these, OK? It's the same structure in both conjoined clauses.
- These cookies are fun to make.
The OP also notes that these cookies is the Direct Object of the infinitive to make and normally what one expects to be moved or missing from an infinitive is its Subject, not its DO. And indeed the subject of each infinitive is missing, but that's normal for indefinites.
The real question is how the infinitive make wound up shorn of both its Su and its DO,
and how the DO of make wound up as the Su of be fun.
And the answer is a minor governed cyclic rule called Tough-Movement.
A "governed" rule is one that requires the presence of some particular (kind of) predicate. We say that the rule is governed by the predicate; in this case, Tough-Movement is governed by be fun.
A governed rule is called "minor" if it only applies to a relatively small number of predicates.
In this case, fun is one of a relative handful of predicates, all taking infinitive complements, e.g: tough, easy, difficult, hard, a bitch, a breeze, a piece of cake, fun, cool, nice.
What the rule does is sort of like A-Raising,
in which the Su of an infinitive winds up as upstairs Su, e.g:
- It seems to be a long way to Tipperary.
- There is likely to be a unicorn in the garden.
- The shit appears to have hit the fan.
Here the boldfaced idiomatic or dummy subjects of seem, likely, and appear
(all of which govern A-Raising) are unambiguously licensed by (or "originated in", as one says when one uses the "movement/raising" metaphor theme) the infinitive complement clauses:
(Extraposition and There-Insertion have generated the It and There dummies,
and the idiom chunk subject in the last sentence clearly goes with hit the fan.)
But this is A-Raising, however, a major governed rule, very frequent with many predicates.
Tough-Movement, by comparison, works exactly the same way as A-Raising, with two differences:
- Tough-Movement raises the Object of the infinitive clause, and not its Subject
- A small set of predicates governs Tough-Movement, and a large set governs A-Raising
(these sets are disjoint, btw; no predicate governs both.)
Solution 2:
I think that there's a complication with the emphasiser(?) 'especially' here that deserves a mention (it's going to get one anyway).
These cookies are tasty and inexpensive.
obviously uses two coordinated predicative adjectives to modify (give some / more information about) the referent, the baked whatsits. The subject is 'These cookies'.
This new game is fun.
shows that 'fun' can be used without shame as a (here predicative) adjective.
These cookies are fun.
seems to be incomplete (the notion of food, rather than eating, being fun is rather stretched. The implication would probably be that they are a weird shape and/or colour.)
These cookies are fun to eat / These cookies are fun to make and fun to eat.
sounds fine, however, with the addition of the 'adjective complement' showing what the fun is actually associated with. Quite a few adjectives readily accept (or even require) complements. Some authorities prefer the term 'modifiers' to 'complements', as they're not always necessary. As seen in OP's example, to-infinitives comprise one type:
She is curious to know . . .
I was sorry to learn . . .
He is quick to take offence.
They are hard to beat.
He is likely to fail the test.
The complication with OP's example is the inclusion of 'especially'. All four of the adjectives above accept the intensifiers 'very', 'really' and if you'll excuse the register 'frightfully'. I'd say that 'fun' doesn't (with the possible exception of 'really' - and 'real' might be considered as acceptable, with 'fun' being so nouny). So I'm preferring the interpretation of 'especially' here as a pragmatic marker emphasising the whole sentence (which makes little difference semantically):
These cookies are fun to make. It's even more fun eating them.
These cookies are fun even to make. But oh, are they fun to eat!
These cookies are fun to make. And THEY ARE FUN TO EAT!