What are some examples of irony?

There are many examples of irony in the story. For example, there is dramatic irony: the reader knows that Santiago Nasar is going to die, but our protagonist seems to be ignorant of that fact. Up until the moment of his death, Santiago acts as if nothing is the matter. His nonchalant and calm manner is ironic in light of the threat against him.
In the story, Santiago talks about his future wedding.

"That's what my wedding's going to be like," he said. "Life will be too short for people to tell about it."
"I don't want any flowers at my funeral," he told me, hardly thinking that I would see to it that there weren't any the next day.

Ostensibly, Santiago looks forward to a consequential wedding. His words, however, are ironic. Although he means that there will not be enough time on earth to expound upon the grandness of his future wedding, Santiago's words turn out to be ominously prophetic. His life actually ends up being too short to even accommodate the possibility of a wedding. Santiago's quip that he does not want flowers at his funeral is also ironic: he does not realize that he will die the next day and that there will be no flowers at his funeral.
According to the story, Santiago is slashed across the stomach by one of the Vicario brothers. His intestines fall out, and the priest later discards the slashed intestines in the garbage pail. Up until his death, Santiago had believed that it was barbaric to handle the human body in such a manner. In fact, he had chided Victoria Guzman for pulling out rabbit intestines by the roots and throwing them to the dogs. It is ironic that the priest pulls out Santiago's mutilated intestines by the roots in order to prepare his body for burial.
Another irony in the story concerns Bayardo san Roman and Angela Vicario. When Bayardo discovers that Angela is not a virgin, he takes her back to her family home. Later, the couple reunite after Angela writes two thousand love letters to Bayardo. The couple's reunion has been facilitated by Angela. Here, Angela has usurped the traditional role of the woman who waits to be wooed by her male lover. The two reunite, but it is not by Bayardo's efforts, which is ironic.