The standard expression is cut and dried, though usages such as That's pretty cut and dry have started to appear more in recent decades, as this NGram shows.
It's a metaphoric reference to grass/hay/herbs/etc. being cut, dried, and thus ready for sale/use (nothing more needs to be done). By extension it comes to mean no more discussion needs to take place. By further extension, no decision or thought is required at all (the ordinary default suffices).
OP's example isn't a very appropriate one. Most people would say the rule was clear-cut (overt, explicit, unambiguous), not cut and dried (fully decided upon, finalised, settled).
1. Did "long time no see"
arrive in U.S. English from forms of pidgin English
spoken separately by both some Native Americans
and some Chinese immigrants?
The earliest recorded examples are from native Americans, but it's plausible it was used in other types of pidgin English at the same time.
2. When did this
turn of phrase first gain the recorded notice of an
American English-speaking author?
It has been recorded by American English-speaking writers in 1900. The author Raymond Chandler used it in a 1939 newspaper and 1940 book.
3. When did the phrase cross over into use by native U.S.
English speakers among themselves?
Chandler presumably helped popularise it with detective stories and film noir of the early forties.
The OED says it's a "Colloq. phr. (orig. U.S.) long time no see, a joc. imitation of broken English, used as a greeting
after prolonged separation."
Their earliest quotation is 1900 from a native American:
1900 W. F. Drannan Thirty-one Years on Plains
(1901) xxxvii. 515 When we rode up to him [sc.
an American Indian] he said: ‘Good mornin. Long
time no see you.’
Their next quotation of 1939 shows it was fully naturalised:
1939 R. Chandler in Sat. Evening Post 14 Oct. 72/4
Hi, Tony. Long time no see.
Their next is also from Chandler, in 1940's Farewell, my Lovely.
Best Answer
In that context, it’s a verb, meaning, in the OED’s definition 'To start up, come forward, begin abruptly or boldly, to say or do something'. It can be inflected, but it is only used colloquially.
The OED’s earliest citation for intransitive use in this sense is dated 1831 and shows a third person singular form: The bishop ups and he tells him that he must mend his manners. These three citations, from 1958, 1973 and 1979 show the past tense upped:
So you upped and fled.
It did no good. I upped and died.
As soon as we could we upped and fled.
In its transitive use, the verb is known, at least in the UK, for the sense 'To drive up and catch (swans, etc.) so as to provide with the mark of ownership', first recorded in 1560-1: For uppyng the ground byrde in porte meade. A citation from 1593 shows both the –ing form and the past participle: That the upping of all those swans . . . may be upped all in on day wt the upping of the Tems.
Swan upping continues on the Thames to this day.