13-Nov-2013 01:16, Dicebot пишет:
On Tuesday, 12 November 2013 at 20:56:34 UTC, Dmitry Olshansky wrote:
If we just had:
//this would invoke compiler's parser at CTFE
auto ast = "x = y;".astof
and have it work at CTFE to return sensible AST (a big if btw).
And then (after some manipulations):
ast.toString() //get back a string of D code
It may help code generation of D --> DSL.
Add there "foo.codeof" in the toolset and it will pretty much give core
needed stuff.
However, it will destroy compilation times if not coupled with compiler
internal parsing/semantic phase.
For me it feels a lot like implementing something as a soft-core or
emulator in software vs producing a bare-metal chip. It's a good idea to
test waters and prototype a soft-thingy before getting dirty. When it
comes to manufacture ASICs the idea should be well tested and could be
actually sold as is already ;)
If we consider that compiler is sort of "hardware" accelerator for
getting ast's of strings and functions alike. Ditto with toString of
ast. Then if somebody comes up with soft-core implementation of "macros"
and shows:
a) Cool benefits of manipulating on ASTs compared to cracking some strings
b) Limitations of this implementation (unhyginic is one)
c) Quantify obvious performance problems
d) Prepare a solid file of use cases
Then we might get people to manufacture ASICs (pay costs, implement in
compiler/spec).
Paraphrasing somebody from C++ ISO committee (I think Herb):
Boost C++ Lambda is a prime reason we had to add lambdas as a core
feature in C++11. If it took these top-notch experts that much of coding
to get only this far and it's still brittle, limited and etc.
... we have no choice but to add it to the language.
Actual "macro" keyword syntax sugar is hardly important to me.
--
Dmitry Olshansky
