Update HOME_EXAM.md

HOME_EXAM.md

@@ -23,7 +23,7 @@ Func
 Params
 ```ebnf
     : "()"
-    | "(" [ "," ], Param ")"
+    | "(" (Param, ",")+ ")"
     ;
 ```
 Param
@@ -338,8 +338,11 @@ Dereference of a referenced expression
 
 ### Function call expression
 ```math
-\frac{<f(e_1,e_2,...,e_n),σ> → <v,σ'>; <e_1,σ> → v; ...; <e_n, σ>→ v}{<f, σ> → v}
+\frac{<f(e), σ> → v}{<f, σ> → \text{ret } v}
 ```
+
+
+
 ``` rust
 fn func() -> i32 {
     1+3