ONT Re: Program Semantics
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| Algebraic Approaches to Program Semantics
|
| Part 1. Denotational Semantics of Control
|
| Chapter 1. An Introduction to Denotational Semantics
|
|
| 1.2. A Simple Fragment of Pascal (cont.)
|
| As a prelude to defining the semantics of statements, we aid the
| reader's intuition with flowschemes for the programming constructs
| in Table 7.
|
| Table 7. Flowschemes for Programming Constructs
| -------------------------------------------------------------
|
| Assignment Statement. I := E
|
| o---------o
| ---->| I := E |---->
| o---------o
|
| Composition. begin S_1; ...; S_n end
|
| o---------o o---------o o---------o
| ---->| S_1 |--->| ... |--->| S_n |---->
| o---------o o---------o o---------o
|
| Conditional. (if B then R else S)
|
| T o---------o
| o-------->| R |-------->o
| / \ o---------o |
| / \ |
| ------>o B o o------>
| \ / |
| \ / o---------o |
| o-------->| S |---------o
| F o---------o
|
| Repetitive Constructs.
|
| (while B do S)
|
| o<-----------------------------------o
| | ^
| | T o---------o |
| | o-------->| S |-------->o
| | / \ o---------o
| v / \
| ------>o B o
| \ /
| \ /
| o-------------->
| F
|
|
| (repeat S until B)
| T
| o--------->
| / \
| o---------o / \
| ------------------->| S |----->o B o
| ^ o---------o \ /
| | \ /
| o<----------------------------o
| F
|
| -------------------------------------------------------------
|
| Manes & Arbib, AAPS, pages 8-9.
|
| Ernest G. Manes & Michael A. Arbib,
|'Algebraic Approaches to Program Semantics',
| Springer-Verlag, New York, NY, 1986.
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