Evaluation of
Expressions: Example 13/16
Example for a + b, where a.value = 10, b.value = 20
{R2.i := F2.s}
R2
{T2.s := R2.s}
{Q2.i := Q1.i + T2.s}
Q2
{Q1.s
:= Q2.s}
{E.s
:= Q1.s}
$
Parser
pushdown:
Semantic
pushdown:
Input: $
Rule:
40/69
E
10
+
20
T1
Q1
F2
R2
F1
R1
i1
e
i2
Illustration:

R2
{T2.s := R2.s}
{Q2.i := Q1.i + T2.s}
Q2
{Q1.s
:= Q2.s}
{E.s
:= Q1.s}
$
R2 ® e {R2.s := R2.i}
T2
Q2
+