6.1 Please complete the following sentence level BNF grammar definition for expressions like:

int myresult = 5 + 1 2 or int VarA = 2.5 + 1.11 + 1 - 3

For simplicity, we assume some of the token level BNF grammar rules are already defined (identifier and literals are defined and can be directly used). For example, in derivation and tree building, you could directly replace literal with 66 in one step. Also, we do not consider other variable definition expression formats, nor do we consider math operators other than + and -.

Sentence level BNF grammar only here. Please fill in the 4 blanks to make the grammar complete.

int_def_exp -> keyword identifier ___ ___

keyword -> int

equal_op -> =

math_exp -> literal + math_exp | ___ | ___

6.2 Please use the defined BNF grammar and write down the left-most derivation for expression:

int myres = 5.5 + 1 2.1

Left-most derivation:

___

6.3 Please draw the parser tree from your derivation for expression int myres = 5.5 + 1 2.1

Your parser tree here: