If you look at Rebol2, R3-Alpha, and Red they all do the same thing with FILE! that they would with text (STRING!) when you pass as the first argument to PARSE:
rebol2>> parse %aaa.txt [some "a" ".txt"] == true r3-alpha>> parse %aaa.txt [some "a" ".txt"] == true red>> parse %aaa.txt [some "a" ".txt"] == true
I've always had the ambition that you be able to PARSE a PORT!. If that's possible, it seems that you should be able to shortcut actually opening and closing the port yourself by saying something like:
parse %some-200-megabyte-file.txt [ some "a" end (print "Your giant file was all the letter A") ] parse http://example.com/some-net-data/ [ thru <title> copy title to </title> (print ["Title was" title]) ]
The vision would be that PARSE would assume when you gave it a FILE! or URL! that you meant to operate on that as a PORT!...opening it, parsing it, and closing it. If you gave it a regular PORT! it would assume you would take care of closing it yourself.
Furthermore, it would be efficient so that it didn't need to load all of it into memory at once. (There could be some heuristic on a "chunk size" it picked automatically, paging in only as much of the file as it needed at a time. But you could perhaps tweak that manually by opening the port yourself and doing some settings. This seems to be a property of the PORT! and not of PARSE, though there may be PARSE-specific settings. Perhaps those settings would be looked for on the port itself as an extensible set of headers, vs. being some strange refinement you'd pass.)
In any case, the appeal of having that work for FILE! and URL! certainly seems to suggest that it's a much better use of the type variety than as a synonym for:
>> did parse as text! %aaa.txt [some "a" ".txt" end] == #[true]
There's clear need for PARSE to run on TEXT!, BINARY!, and BLOCK! input. I'm not sure how this applies to INTO. There also might be a parse/only (or parse/into? which would be type-preserving?)
Not just for PARSE: a General Philosophy of ANY-SERIES!
This ties into what I think should be a very restrained tendency to use ANY-STRING! types in ways that make them equivalent to the behavior on TEXT!.
I've said similar things about why type of first ['''a] should not be conflated with plain WORD!. There should be a default of discernment; leaving the room open for distinct meanings.
So be on the lookout for cases where a datatype is being underused, even if it's not able to do the ideal magic today. Seeing PARSE run on PORT! is a pretty big wishlist item for me, so maybe it's not impossible that it could happen... (!)