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Miles Bader wrote:
"steve donovan" <> writes:
(g)awk is a lovely language. Look at those old books by Jon Bentley and
you'll see the oldtimers prototyping things in AWK. Was probably the
first scripting language, apart from BASIC and shell ;)

Yes, I agree, awk is wonderful.  In many ways it's a far better
language, despite its limitations, than most of its purported
replacements (Lua excepted of course :-).

I think I can definitively pontificate on awk --- I wrote a compiler in it once. A full reverse-descent strongly typed bytecode-targeting language. Thinking back now, I must have been insane.

The biggest problems with awk: firstly, everything's a string:

1 == "1"     true
1 == "1.0"   false
1.0 == "1.0" false

This makes doing anything involving maths really unpleasant. You keep having to do 'n + 0' to force type conversion.

Secondly, the '' operator is string concatenation:

"foo" "bar"  -> "foobar"
1 "bar"      -> "1bar"
1 1.0        -> "11"

...which as you can see interacts nastily with the first problem. This can lead to some *ludicrous* typos.

Thirdly, no local variables; you fake them instead by using extra function arguments:

foo(arg1 arg2 var1 var2) { ... }

...which can obviously go terribly wrong if you pass too many arguments into a function.

Fourthly, no arrays.

This is a big one. There are associative arrays, but both the key and the value must be a string. This makes it rather hard to store complex data structures. There's syntactic sugar for multidimensional arrays of the form array[foo, bar], but that's identical to array[foo SUBSEP bar] where SUBSEP is a string containing a non-printing character... which makes *enumerating* such arrays highly entertaining!

That said, the entire compiler for my language came out at 1611 lines of highly structured and fairly readable code; and it ran astonishingly fast, too. When I rewrote the compiler in itself, compiled it with the awk bootstrap compiler and tried the result, it turned out to be considerably slower than the awk version (at which point I largely lost interest).

awk is a great language for things within its problem domain --- for text parsing, it's still considerably more elegant than Lua. It's got scaling problems, but for things that don't hit those limits, it's well worth checking out. To me, it forms a very nice middle ground between sed and perl (which I can't stand). The C-like syntax is nice and familiar, and the built-in support for things like regexps are first-rate. It's an ideal example of why domain-specific languages can be good.

But I wouldn't recommend writing a compiler in it.

If anyone actually *cares*, my doomed toy language Mercat and both versions of the compiler can be found here: the package. ( is a later version where the language has acquired features that no longer work with the awk compiler.)

David Given