On Mon, 25 Aug 2008, Reini Urban wrote:
To clarify my bold statement:
The ALGOL-like syntax is not "sane" because,
* it is hard to parse,
Not actually true. It's just different to parse. And, in general Parrot
optimizes for making code easy to *read* even if it is slightly harder
to parse. We have the most powerful parsing tools on the planet at our
disposal, there's no reason to push the difficult work on the code
maintainers.
* it forbids our keywords AND, NOT and OR as config_hash keys
and platform names.
This isn't an onerous restriction.
With lisp syntax there's a clear distinction
between operator and arguments, with mixed arg op arg syntax
it is not clear and as hard to understand as spoken language.
If your background is lisp-like syntax, then yes it's easy to
understand. But our primary target audience for Parrot is not people
with a background in Lisp, it's people with a background in modern
dynamic languages like Lua, Perl, PHP, Python, and Ruby. All of which
are more familiar with infix notation.
Andy Dougherty wrote:
What we did in perl5's build system was to recognize that we didn't have
to invent or borrow any new syntax at all. The languages we were using to
write the Makefiles (namely /bin/sh and perl) already had sophisticated
interpolation and conditional syntax capabilities. We used here-documents
and interpolation instead of macro substitution. We used the language's
built-in conditional and flow control syntax to express complex ideas.
This particular chunk of syntax is indeed parsed by a Perl preprocessor
for the Makefile. But, that doesn't necessarily mean that we want to
directly eval/interpolate Perl conditional syntax. For one thing, it
won't always be parsed by a Perl preprocessor, it'll eventually be
parsed by a PGE-based preprocessor.
Alternatively, we could use Makefile conditionals, but those are
cumbersome. And, this particular pair of preprocessor directives give us
a way to block out lines during preprocessing, so that 'make' never has
to parse them at all.
Picking any one HLL to mimic is problematic in our multi-lingual
environment. But, we definitely want to pick syntax that will seem
familiar to our primary HLL targets.
Allison
