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sav08:semantics_of_field_reads_and_writes [2009/03/18 10:02] vkuncak |
sav08:semantics_of_field_reads_and_writes [2015/04/21 17:30] (current) |
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| Use function update construct: | Use function update construct: | ||
| - | \[ | + | \begin{equation*} |
| f = f(x:=y) | f = f(x:=y) | ||
| - | \] | + | \end{equation*} |
| State variable $f$, which denotes a function, is assigned an updated version of this function. | State variable $f$, which denotes a function, is assigned an updated version of this function. | ||
| ++++ | ++++ | ||
| - | What about null pointer checks? | ||
| - | |||
| - | Examples: | ||
| - | y = x.next.next | ||
| - | x.next.next.prev = y | ||
| - | (x = null | x.next == y) | ||
| - | |||
| - | Statement simplification. | ||
| - | |||
| - | Short-circuit evaluation. | ||
| - | |||
| - | Compiler intermediate representation is sometimes more convenient than source code | ||
| - | * or verification system can repeat the compilation process from source to relations (guarded commands) | ||
| - | * [[:compilation:top]] | ||