On 07/07/2012 13:05, Jacob Carlborg wrote:
On 2012-07-07 03:12, Jonathan M Davis wrote:
Now, the issue of a "strong, dependable formalization of D's syntax" is
another thing entirely. Porting dmd's lexer and parser to Phobos would
keep
the Phobos implementation in line with dmd much more easily and avoid
inconsistencies in the language definition and the like. However, if
we write a
new lexer and parser specifically for Phobos which _doesn't_ port the
lexer or
parser from dmd, then that _would_ help drive making the spec match the
compiler (or vice versa). So, I agree that could be a definite
argument for
writing a lexer and parser from scratch rather than porting the one
from dmd,
but I don't buy the bit about it smothering parser generators at all.
I think
that the use cases are completely different.
I think the whole point of having a compiler as a library is that the
compiler should use the library as well. Otherwise the two will get out
of sync.
Just look at Clang, LLVM, LLDB and Xcode, they took the correct
approach. Clang and LLVM (and I think LLDB) are available as libraries.
Then the compiler, debugger (lldb) and IDE uses these libraries as part
of their implementation. They don't have their own implementation that
is similar to the libraries, making it "easy" to stay in sync. They
_use_ the libraries as libraries.
This is what DMD and Phobos should do as well. If it's too complicated
to port the lexer/parser to D then it would be better, at least as a
first step, to modify DMD as needed.
I tried that. This is almost impossible, dmd's parser and AST are very
tightly mixed with dmd's internals.
