[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: put library <body> at top-level

Tony Garnock-Jones wrote:

"Source code in files. How quaint. How 70's." (Kent Beck)


If prefer, replace "file" with "something that has a URI".


Scheme code doesn't have to live anywhere in particular - it can be
sourced from anywhere, from files, from stdin, from an email message,
from a database - the only constraint on scheme code is that it is an
S-expression.


Right, but we're talking about "named libraries".  Once something has
a name, you can give it a URI.

If you have multiple named resources A, B, and C nested within a
resource X, then we have standard way of naming them: X/A, X/B, and X/C.
This all works best if A, B, and C are separate "units of characters",
rather than being concatenated together.


List syntax is already suitable for sequencing S-expressions within an
S-expression. Files provide a second-class means of sequencing
S-expressions. Recovering a complete list of S-expressions from a file
requires some small-but-nonzero amount of work.


Beside the point: a collection of libraries is not a "sequence": It is
a *mapping*, from names to libraries.


A file is not always the best granularity for a library


True, but we're trying to standardize a useful portable basic feature.


- sometimes many
small libraries are best expressed in a single file,


I think this is fairly rare, and not a very important use case.
If they're small, why should they be separate libraries?

> and sometimes a

single library is best expressed in multiple files.


Right, though this not directly handled by the proposal.  It can
be handled by using a compound library importing and re-exporting
smaller libraries.


The scoping of the |library| form can be unclear if forms /following/
the declaration are to be considered part of the library:

  (library "mylib" "scheme://r6rs")
  (define library (compose write list))
  (library "otherlib" "scheme://r6rs")
  (define number 17)


The proposal doesn't support nested library forms, so I don't see
why this is relevant.
--
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/