How does Dally slapping Ponyboy impact the text as a whole?

In Chapter 3, Ponyboy loses track of time while he is lying down next to Johnny in a lot, looking at the stars. Ponyboy races home and sees that his older brother, Darry, is awake reading the newspaper. When he enters his house, Darry flips out and begins to yell at Ponyboy. In the midst of the heated argument, Sodapop attempts to chime in, and Darry tells him to "shut his trap." Ponyboy yells at Darry not to raise his voice at Sodapop and Darry slaps Ponyboy in the face. Ponyboy is stunned and opens the door to runaway. Darry yells to Ponyboy that he didn't mean to hit him, but it is too late. Ponyboy runs straight to get Johnny and tells him what happened. Ponyboy and Johnny run to a local park where they are confronted by a gang of Socs.

Darry slapping Ponyboy sets the plot of the story in motion. Shortly after Darry slaps Ponyboy, Ponyboy and Johnny go to hang out in the park where they are jumped by a group of Socs. Johnny stabs and kills one of the Soc gang members, which forces the boys to flee the city. If Darry had never slapped Ponyboy, then Ponyboy would have never ran away and met up with Johnny. Another reason of how Darry slapping Ponyboy impacts the text is in regards to Ponyboy's feelings about his older brother. Ponyboy's feelings about Darry change as he matures and gains perspective throughout the novel. Initially, Ponyboy thinks that Darry slapped him because he was sick of him and wanted him out of the house. Later on, when Ponyboy witnesses Darry cry at the hospital, he realizes that Darry made a mistake and that Darry truly cares about him. At he end of the novel, Ponyboy understands that Darry is still a young man with a lot of responsibility and realizes why Darry reacted the way he did.