Chapter 4, Problem 7E

Explanation of Solution

Attribute grammar:

• The following grammar compute the arithmetic value of tokens derived from the symbols.

$\begin{array}{l}{\text{E}}_1\to {\text{E}}_2\text{ + T }\Rightarrow {\text{E}}_1{\text{.seq := cat(E}}_2\text{.seq, T}\text{.seq, "+")}\\ {\text{E}}_1\to {\text{E}}_2\text{ - T }\Rightarrow {\text{E}}_1{\text{.seq := cat(E}}_2\text{.seq, T}\text{.seq, }"-")\\ \text{E }\to \text{T }\Rightarrow \text{E}\text{.seq := T}\text{.seq}\\ {\text{T}}_1\to {\text{T}}_2\text{* F }\Rightarrow {\text{T}}_1{\text{.seq := cat(T}}_2\text{.seq, F}\text{.seq, "}\times \text{")}\end{array}$$\begin{array}{l}{\text{T}}_1\to {\text{T}}_2\text{ / F }\Rightarrow {\text{T}}_1{}_{}\end{array}$