Soldiers’ Pay is by and large without “modernist tricks,” stylistically speaking, excepting Faulkner’s use of parentheses — which I don’t know if I’ve encountered in an author before him. (Feel like Virginia Woolf will employ devices like this, particularly in To the Lighthouse, though that was published a year after this in 1927.)
You could say what’s inside the paren is the voice of the Greek Chorus, a comment on the action, though it’s generally just a character’s unattributed thought, somewhat like an aside in theater.
A little more striking is when he leaves *out* of the paren what he should have included within them, which he does in a least one spot — obliterating that line between comment and thing commented on, between character thought and author narration — which I think he pursues more seriously in his later books. (Soldiers’ Pay is his first published book.)
When he does this, the effect is of objectifying the character’s thought. Without the privilege of parentheses or quotes to set it off, the thought becomes a thing and part of the landscape, something present in a room like a table might be. (A character didn’t think something: rather, there existed this thought. This thought, belonging to no one, was part of the surroundings.)
.i`` * ^ / . . . . . ` `~ 