Proof: Write Stmt Tab Unchanged Expr32
Let's prove the following theorem:
if the following are true:
- the line at time 32 = 4
- the tab at time 32 = 2
- statement at line 4, tab 2 = self."y" = 0
- expression state at time 32 = "end_expr"
then the tab at time 33 = 2
Proof:
Given
1 | the line at time 32 = 4 |
---|---|
2 | the tab at time 32 = 2 |
3 | statement at line 4, tab 2 = self."y" = 0 |
4 | expression state at time 32 = "end_expr" |
# | Claim | Reason |
---|---|---|
1 | the tab at time (32 + 1) = the tab at time 32 | if the line at time 32 = 4 and the tab at time 32 = 2 and statement at line 4, tab 2 = self."y" = 0 and expression state at time 32 = "end_expr", then the tab at time (32 + 1) = the tab at time 32 |
2 | the tab at time (32 + 1) = 2 | if the tab at time (32 + 1) = the tab at time 32 and the tab at time 32 = 2, then the tab at time (32 + 1) = 2 |
3 | 32 + 1 = 33 | 32 + 1 = 33 |
4 | the tab at time (32 + 1) = the tab at time 33 | if 32 + 1 = 33, then the tab at time (32 + 1) = the tab at time 33 |
5 | the tab at time 33 = 2 | if the tab at time (32 + 1) = the tab at time 33 and the tab at time (32 + 1) = 2, then the tab at time 33 = 2 |
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