Saturday, June 15, 2013

Go to statement considered harmful

Link to the (classic) article at the ACM. The abstract follows.

To many people, Dijkstra's letter to the Editor of Communications of the A CM, published in March 1968, marks the true beginning of structured programming. That it influenced the industry is clear, if for no other reason than for the articles it spawned, ranging from "IF-THEN-ELSE Considered Harmful," to "The Else Must Go, Too," to "Programming Considered Harmful."
In form and content, Dijkstra's letter is similar to his 1965 paper, which appears first in this collection. Description of the inverse relationship between a programmer's ability and the density of goto statements in his program is repeated, as is the emphasis on the limited ability of the human brain. Much of the discussion is somewhat theoretical in nature, and the typical COBOL programmer will hunger for some coding examples so that he can see why goto statements make program logic harder to understand.
Echoing his 1965 paper, the last few paragraphs underscore once again why the subject of structured programming stayed out of the mainstream of the data processing industry for so long. As Dijkstra points out, goto statements were a subject of discussion among academicians as far back as 1959. But even today, people whom Dijkstra acknowledges --- names like Wirth, Hoare, Strachey, and Landin --- are not well known to business-oriented or scientificoriented programmers, so it should be no surprise that their ideas have languished for so many years.

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