Here's some code from one of my vocabs:
: do-load ( -- )
try-everything keys "../load-everything-vocabs" [ . ] with-file-writer ;
: do-tests ( -- )
run-all-tests keys "../test-all-vocabs" [ . ] with-file-writer ;
: do-benchmarks ( -- ) run-benchmarks "../benchmarks" [ . ] with-file-writer ;
: do-all ( -- )
bootstrap-time get "../boot-time" [ . ] with-file-writer
[ do-load ] runtime "../load-time" [ . ] with-file-writer
[ do-tests ] runtime "../test-time" [ . ] with-file-writer
do-benchmarks ;
Someone could argue that I could factor out the "[ . ] with-file-writer".
Sure, but you know what? In a pinch, this did the trick and it looks fine.
Enter forced encodings:
: do-load ( -- )
try-everything keys "../load-everything-vocabs" utf8 [ . ] with-file-writer ;
: do-tests ( -- )
run-all-tests keys "../test-all-vocabs" utf8 [ . ] with-file-writer ;
: do-benchmarks ( -- )
run-benchmarks "../benchmarks" utf8 [ . ] with-file-writer ;
: do-all ( -- )
bootstrap-time get "../boot-time" utf8 [ . ] with-file-writer
[ do-load ] runtime "../load-time" utf8 [ . ] with-file-writer
[ do-tests ] runtime "../test-time" utf8 [ . ] with-file-writer
do-benchmarks ;
That's pretty ridiculous. It's so silly that now I'm really compelled to
factor out 'utf8 [ . ] with-file-writer', whereas before I found it
tolerable.
The code would've worked as is if we had default encodings.
Now, lets suppose that one day I got in trouble for not explicitly specifying
the encoding here. As you can see, 'do-all' calls all the other do-* words.
If I had felt the need to set the encoding explicitly, dynamic scope would
have saved the day:
: do-all ( -- )
[
utf8 set-default-encoding
...
]
with-scope ;
Alright, let's say that dynamic scoping doesn't give you warm fuzzies. You
want to explicity state the encoding of a particular stream. This is easy if
you have created a stream and it's on the stack; you just call a word like
set-encoding ( stream encoding -- stream ), e.g.:
"out.txt" <file-writer> utf16 set-encoding
Now your stream is immune to the haze of dynamic scope.
So how do you set the encoding with stream combinators where you don't ever
have the stream on the stack? An example of one of these combinators
is 'with-file-writer'. Remember that in the quotation you can always get to
the stream via the stdio variable. So you could set the encoding explicitly
like so:
"out.txt"
[
stdio get utf16 set-encoding
...
]
with-file-writer
One big point of the api I'm proposing is that you aren't forced to change
your code, but you can if you want to, in various ways which suit your needs.
This sort of elegance is what I've come to expect from Factor.
Here's my bold claim:
There are many cases where the programmer won't need to care about text
encoding.
Therefore:
The language shouldn't force the programmer to "think" about it.
It's like forcing your kids to pray; programmers are just going to murmur
the 'utf8' incantations mindlessly. Better to just leave the good book nearby
and someday, when they need it, it'll be there for them.
Sure, I can code my way around all these annoyances. I can probably even build
up the whole api I want as a wrapper over the core api. But is it a good sign
when coders start to do things like this?
Ed
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