In what situations would you use came over come and vice versa?
For my example, I was talking to my roommate and I told him:
You should have came to the party.
Then I thought maybe that wasn't grammatically correct. I thought it was possibly:
You should have come to the party.
Which one of these is "correct"?
You were right the second time.
Should have is always followed by a past participle, one of the basic forms of verbs.
From http://www.ecenglish.com/learnenglish/lessons/should-have-past-participle :
We use should have + past participle to talk about things we regret.
I got really wet walking home last night, I should have taken an umbrella.
The speaker did not take an umbrella when she went out last night so she got wet. She regrets that she did not take her umbrella.
Regret (verb/noun) is to feel sorry about something that happened or did not happen in the past.
I should have called you sooner.
You should have spoken to me before deciding.
The past participle of come is also come.
From http://www.usingenglish.com/reference/irregular-verbs/come.html :
Conjugation of 'To Come'
Base Form: Come
Past Simple: Came
Past Participle: Come
3rd Person Singular: Comes
Present Participle/Gerund: Coming
"You should have come to the party" is correct. Since the "should have" is already placing the statement in the past tense.
"Should have" requires the verb's participle ("come") rather than past tense ("came").
"You should have come to the party" is right. Phrases like "should have", "could have" and "would have" always follow with a past participle, not past tense.
To clear your confusion, Let me inform you that "come" may look like present tense. But yes, It is also past participle of itself.
"You should have come to last night's party."
is grammatically correct. However, if you're no longer at the party's venue then, logically, I think it would be more accurate to say:
"You should have gone to last night's party."
