Why is there no or or and ?
F i L
witte2008 at gmail.com
Fri Feb 17 12:52:55 PST 2012
H. S. Teoh wrote:
> Are you referring to:
>
> int x = 10;
>
> vs.
>
> x = 10;
>
> ?
>
> In that case I would still prefer :=, since the first can be
> thought of
> as shorthand for "int x; x := 10".
I'm not sure what you're asking/saying here. What I mean is that
there needs to be some distinction between variable declarations
and variable assignment.
Foo: class
{
x: int
// lots of code
bar: void()
{
x := 0 // set Foo.x or create a local 'x' variable?
}
}
>> I don't think lines need ending marks at all.
>
> This leads to ambiguity problems if it's unclear whether two
> adjacent
> lines are a single statement or two. It also makes the grammar
> much
> harder to implement in a parser, because it can't easily tell
> between
> the end of a statement and a wrapped line. Having a statement
> separator
> is a good thing.
I don't think this leads to ambiguity problems, I've thought
about this before and can't come up with any that aren't easily
addressed. Also, I don't think is much harder to parse at all,
just when the statement is determined to stop needs to be
slightly more intelligent. If we can understand the code without
ending-marks, a compiler should be able to understand it as well.
This is something I'm experimenting with at the moment with LLVM.
> Wait, you're trying to reimplement D syntax??
Nothing so robust. Mostly I'm playing around with compiler design
while refreshing my C++ abilities (which it's been awhile). My
main focus is to try and build a simplistic compiler around the
concept of having an AST designed to stay in memory and be
dynamically submitted changes and on-demand compilation (like
NRefactory, or MS Roslyn). Kinda like and interrupter only
designed with the goal of 1) Non-text forms of manipulation and
logic construction, and 2) modularized AST libraries as
development reflection tools (think objects overview,
code-completion, etc).
I'm thinking of textual syntax as more of "commands" to submit
AST nodes, so there's no real "syntax" beyond what's saved in a
file, which isn't really suppose to be humanly read/written
though a traditional text editor. I think "standard tools" (+
modularized to used by other tools) are as important as standard
libraries.
Just a hobby :)
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