整數四則運算 syntax
包含
- +, -, *, /
- 變數、整數
":="此符號為"定義為"
"ADDSUB"，為"+","-"
"MULDIV"，為"*","/"
END := 一個句子的結束
INT := 整數
VAR := 變數
ASSIGN := "="
LPAREN := "("
RPAREN := ")"
UNKNOWN := else case
SPACE := 空白
NUL := 空值
*syntax
stat -> END | exp END
exp -> VAR ASSIGN term
term -> op ADDSUB term | factor
factor -> op MULDIV term | base
base -> LPAREN term RPAREN | op
op -> VAR | INT
First Set
First(stat) = {END, First(exp)} = {END, VAR}
First(exp) = {VAR}
First(term) = {First(op), First(factor)} = {LPAREN, VAR, INT}
First(factor) = {First(op), First(base)} = {LPAREN, VAR, INT}
First(base) = {LPAREN, First(op)} = {LPAREN, VAR, INT}
First(op) = {VAR, INT}
Follow Set (未使用)
Follow(stat) = {$}
Follow(exp) = {END}
Follow(term) = Follow(factor) U {END, RPAREN}
Follow(factor) = Follow(term)
Follow(base) = Follow(factor)
Follow(op) = {ADDSUB, MULDIV} U Follow(base) = {ADDSUB, MULDIV} U Follow(factor)
