[TUHS] A few comments on porting the Bourne shell

[Douglas McIlroy]

> segaloco via TUHS writes:
>> I think that's a good point that scripting problems may be
>> a symptom of the nature of the tools being used in them.

> I think that you're hinting at something different.

> To the best of my recollection, scripting languages were originally
> intended and used for the automation of repetitive personal tasks;
> making it easier for users who found themselves typing the same
> stuff over and over again.

Indeed!

> Somewhere along the line people forgot
> how to use a compiler and began writing large systems in a variety
> of roughly equivalent but incompatible interpreted languages.  Can
> one even boot linux without having several different incompatible
> versions of Python installed today?  So I don't think that it's the
> nature of the tools; I think that it's people choosing the wrong
> tools for the problems that they're trying to solve.

> Jon

The forgotten compilers were typically used to supply glue
to paste major tools together. The nature of that glue---often
simple data reformatting--inspired tools like sed and awk.
Each use of a tool became a process that saved many minutes
of work that would in a scriptless world be guided by hand,
boringly and unreliably.

Yet glue processes typically did only microseconds of
"real" work. In the name of efficiency, the operations began
to be incorporated directly into the shell. The first
inklings of this can be seen in "echo" and various forms
of variable-substitution making their way into the v7
shell. The phenomenon proliferated into putting what were
typically canned sed one-liners (but not sed itself) into
the shell.

Lots of specializations crowded out  universality. A side
effect was an explosion of knowledge required to write
or understand code. Such is the tragedy of "forgetting
compilers".

Doug