question on loading HLL bytecode

[Allison Randal]

In a step toward the milestone task on building external languages, I've 
added a new opcode 'load_language'. I takes a single argument, the name 
of an HLL, and locates the main language compiler file in one of 3 
standard locations and loads it. Either:

languages/abc/abc.pir
(for languages in the repository in the standard directory)

or

runtime/parrot/languages/nqp/nqp.pir
(install location in a working copy for languages in the repository but 
not in the 'languages/' directory, or for languages outside the repository)

or

/usr/lib/parrot/languages/perl6/perl6.pir
(real install location, also configurable by --prefix)


The 'load_language' opcode also adds the include and dynext paths 
relative to that main compiler file to the standard search. Either:

languages/abc/include
languages/abc/dynext
or
runtime/parrot/languages/nqp/include
runtime/parrot/languages/nqp/dynext
or
/usr/lib/parrot/languages/perl6/include
/usr/lib/parrot/languages/perl6/dynext

It doesn't add the language library path to the standard library path, 
because that would collapse all the namespaces for all the HLLs. The 
language search paths will also be relative to the main compiler file:

languages/abc/library
or
runtime/parrot/languages/nqp/library
or
/usr/lib/parrot/languages/perl6/library

So, here's the question: Is it better to add a two-argument form of 
'load_bytecode' so you can specify:

   load_bytecode "hllname", "path/to/MyLib.pir"

Or, to treat any path passed to 'load_bytecode' that starts with 
'languages/hllname/' as a "virtual path"?

   load_bytecode "languages/hllname/path/to/MyLib.pir"

I prefer the first, as it's a cleaner interface, and better separation 
of code that does very different things. Also, it could be extended so 
that passing in an HLL source file automatically compiles it to 
PIR/bytecode if the PIR/bytecode doesn't exist already:

   load_bytecode "nqp", "path/to/MyLib.nqp"

Does the two argument form potentially cause problems for compiler 
writers? I'm especially thinking of generated code.

Allison