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another draft of NEWS

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* NEWS: Another draft.
This commit is contained in:
Andy Wingo 2009-06-19 11:19:34 +02:00
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513
NEWS
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@ -5,7 +5,21 @@ See the end for copying conditions.
Please send Guile bug reports to bug-guile@gnu.org.
Changes in 1.9.1 (changes since the 1.8.x series):
Changes in 1.9.0 (changes since the 1.8.x series):
* New modules (see the manual for details)
** `(srfi srfi-18)', more sophisticated multithreading support
** `(ice-9 i18n)', internationalization support
** `(rnrs bytevector)', the R6RS bytevector API
** `(system xref)', a cross-referencing facility (FIXME undocumented)
* Changes to the stand-alone interpreter
** Guile now can compile Scheme to bytecode for a custom virtual machine.
Compiled code loads much faster than Scheme source code, and runs around
3 or 4 times as fast, generating much less garbage in the process.
** The stack limit is now initialized from the environment.
@ -13,11 +27,31 @@ If getrlimit(2) is available and a stack limit is set, Guile will set
its stack limit to 80% of the rlimit. Otherwise the limit is 160000
words, a four-fold increase from the earlier default limit.
** Fix bad interaction between `false-if-exception' and stack-call.
** New environment variables: GUILE_LOAD_COMPILED_PATH,
GUILE_SYSTEM_LOAD_COMPILED_PATH
Exceptions thrown by `false-if-exception' were erronously causing the
stack to be saved, causing later errors to show the incorrectly-saved
backtrace. This has been fixed.
GUILE_LOAD_COMPILED_PATH is for compiled files what GUILE_LOAD_PATH is
for source files. It is a different path, however, because compiled
files are architecture-specific. GUILE_SYSTEM_LOAD_COMPILED_PATH is like
GUILE_SYSTEM_PATH.
** New read-eval-print loop (REPL) implementation
Running Guile with no arguments drops the user into the new REPL. While
it is self-documenting to an extent, the new REPL has not yet been
documented in the manual. This will be fixed before 2.0.
** New `guile-tools' commands: `compile', `disassemble'
Pass the --help command-line option to these commands for more
information.
* Changes to Scheme functions and syntax
** Procedure removed: `the-environment'
This procedure was part of the interpreter's execution model, and does
not apply to the compiler.
** Files loaded with primitive-load-path will now be compiled
automatically.
@ -38,30 +72,191 @@ ccache's behavior for C files.
To inhibit autocompilation, set the GUILE_AUTO_COMPILE environment
variable to 0, or pass --no-autocompile on the Guile command line.
** New environment variables: GUILE_LOAD_COMPILED_PATH,
GUILE_SYSTEM_LOAD_COMPILED_PATH
Note that there is currently a bug here: automatic compilation will
sometimes be attempted when it shouldn't.
GUILE_LOAD_COMPILED_PATH is for compiled files what GUILE_LOAD_PATH is
for source files. It is a different path, however, because compiled
files are architecture-specific. GUILE_SYSTEM_LOAD_COMPILED_PATH is like
GUILE_SYSTEM_PATH.
For example, the old (lang elisp) modules are meant to be interpreted,
not compiled. This bug will be fixed before 2.0. FIXME 2.0: Should say
something here about module-transformer called for compile.
** New global variables: %load-compiled-path, %load-compiled-extensions
** New POSIX procedures: `getrlimit' and `setrlimit'
These are analogous to %load-path and %load-extensions.
Note however that the interface of these functions is likely to change
in the next prerelease.
** New installation directory: $(pkglibdir)/1.9/ccache
** New procedure in `(oops goops)': `method-formals'
If $(libdir) is /usr/lib, for example, Guile will install its .go files
to /usr/lib/guile/1.9/ccache. These files are architecture-specific.
** BUG: (procedure-property func 'arity) does not work on compiled
procedures
** scm_primitive_load_path has additional argument, exception_on_error
This will be fixed one way or another before 2.0.
** scm_stat has additional argument, exception_on_error
** New procedures in (ice-9 session): `add-value-help-handler!',
`remove-value-help-handler!', `add-name-help-handler!'
`remove-name-help-handler!', `procedure-arguments',
** New entry into %guile-build-info: `ccachedir'
The value and name help handlers provide some minimal extensibility to
the help interface. Guile-lib's `(texinfo reflection)' uses them, for
example, to make stexinfo help documentation available. See those
procedures' docstrings for more information.
Probably should be removed?
`procedure-arguments' describes the arguments that a procedure can take,
combining arity and formals. For example:
(procedure-arguments resolve-interface)
=> ((required . (name)) (rest . args))
Additionally, `module-commentary' is now publically exported from
`(ice-9 session).
** Deprecated: `procedure->memoizing-macro', `procedure->syntax'
These procedures will not work with syncase expansion, and indeed are
not used in the normal course of Guile. They are still used by the old
Emacs Lisp support, however.
** New language: ECMAScript
Guile now ships with one other high-level language supported,
ECMAScript. The goal is to support all of version 3.1 of the standard,
but not all of the libraries are there yet. This support is not yet
documented; ask on the mailing list if you are interested.
** Defmacros may now have docstrings.
Indeed, any macro may have a docstring. `object-documentation' from
`(ice-9 documentation)' may be used to retrieve the docstring, once you
have a macro value -- but see the above note about first-class macros.
Docstrings are associated with the syntax transformer procedures.
** The psyntax expander now knows how to interpret the @ and @@ special
forms.
** The psyntax expander is now hygienic with respect to modules.
Free variables in a macro are scoped in the module that the macro was
defined in, not in the module the macro is used in. For example, code
like this works now:
(define-module (foo) #:export (bar))
(define (helper x) ...)
(define-syntax bar
(syntax-rules () ((_ x) (helper x))))
(define-module (baz) #:use-module (foo))
(bar qux)
It used to be you had to export `helper' from `(foo)' as well.
Thankfully, this has been fixed.
** New function, `procedure-module'
While useful on its own, `procedure-module' is used by psyntax on syntax
transformers to determine the module in which to scope introduced
identifiers.
** `eval-case' has been deprecated, and replaced by `eval-when'.
The semantics of `eval-when' are easier to understand. It is still
missing documentation, however.
** Guile is now more strict about prohibiting definitions in expression
contexts.
Although previous versions of Guile accepted it, the following
expression is not valid, in R5RS or R6RS:
(if test (define foo 'bar) (define foo 'baz))
In this specific case, it would be better to do:
(define foo (if test 'bar 'baz))
It is certainly possible to circumvent this resriction with e.g.
`(module-define! (current-module) 'foo 'baz)'. We would appreciate
feedback about this change (a consequence of using psyntax as the
default expander), and may choose to revisit this situation before 2.0
in response to user feedback.
** Defmacros must now produce valid Scheme expressions.
It used to be that defmacros could unquote in Scheme values, as a way of
supporting partial evaluation, and avoiding some hygiene issues. For
example:
(define (helper x) ...)
(define-macro (foo bar)
`(,helper ,bar))
Assuming this macro is in the `(baz)' module, the direct translation of
this code would be:
(define (helper x) ...)
(define-macro (foo bar)
`((@@ (baz) helper) ,bar))
Of course, one could just use a hygienic macro instead:
(define-syntax foo
(syntax-rules ()
((_ bar) (helper bar))))
** Guile's psyntax now supports docstrings and internal definitions.
The following Scheme is not strictly legal:
(define (foo)
"bar"
(define (baz) ...)
(baz))
However its intent is fairly clear. Guile interprets "bar" to be the
docstring of `foo', and the definition of `baz' is still in definition
context.
** Macros need to be defined before their first use.
It used to be that with lazy memoization, this might work:
(define (foo x)
(ref x))
(define-macro (ref x) x)
(foo 1) => 1
But now, the body of `foo' is interpreted to mean a call to the toplevel
`ref' function, instead of a macro expansion. The solution is to define
macros before code that uses them.
** Functions needed by macros at expand-time need to be present at
expand-time.
For example, this code will work at the REPL:
(define (double-helper x) (* x x))
(define-macro (double-literal x) (double-helper x))
(double-literal 2) => 4
But it will not work when a file is compiled, because the definition of
`double-helper' is not present at expand-time. The solution is to wrap
the definition of `double-helper' in `eval-when':
(eval-when (load compile eval)
(define (double-helper x) (* x x)))
(define-macro (double-literal x) (double-helper x))
(double-literal 2) => 4
See the (currently missing) documentation for eval-when for more
information.
** New variable, %pre-modules-transformer
Need to document this one some more.
** Temporarily removed functions: `macroexpand', `macroexpand-1'
`macroexpand' will be added back before 2.0. It is unclear how to
implement `macroexpand-1' with syntax-case, though PLT Scheme does prove
that it is possible.
** New reader macros: #' #` #, #,@
@ -253,223 +448,6 @@ XXX Need to decide whether to document this for 2.0, probably should:
make-syncase-macro, make-extended-syncase-macro, macro-type,
syncase-macro-type, syncase-macro-binding
** `(ice-9 syncase)' has been deprecated.
As syntax-case is available by default, importing `(ice-9 syncase)' has
no effect, and will trigger a deprecation warning.
** Fix bug in `module-bound?'.
`module-bound?' was returning true if a module did have a local
variable, but one that was unbound, but another imported module bound
the variable. This was an error, and was fixed.
** BUG: Automatic compilation will be attempted when it shouldn't.
For example, the old (lang elisp) modules are meant to be interpreted,
not compiled. This bug will be fixed before 2.0. FIXME 2.0: Should say
something here about module-transformer called for compile.
** Defmacros may now have docstrings.
Indeed, any macro may have a docstring. `object-documentation' from
`(ice-9 documentation)' may be used to retrieve the docstring, once you
have a macro value -- but see the above note about first-class macros.
Docstrings are associated with the syntax transformer procedures.
** `eval-case' has been deprecated, and replaced by `eval-when'.
The semantics of `eval-when' are easier to understand. It is still
missing documentation, however.
** Guile is now more strict about prohibiting definitions in expression
contexts.
Although previous versions of Guile accepted it, the following
expression is not valid, in R5RS or R6RS:
(if test (define foo 'bar) (define foo 'baz))
In this specific case, it would be better to do:
(define foo (if test 'bar 'baz))
It is certainly possible to circumvent this resriction with e.g.
`(module-define! (current-module) 'foo 'baz)'. We would appreciate
feedback about this change (a consequence of using psyntax as the
default expander), and may choose to revisit this situation before 2.0
in response to user feedback.
** Defmacros must now produce valid Scheme expressions.
It used to be that defmacros could unquote in Scheme values, as a way of
supporting partial evaluation, and avoiding some hygiene issues. For
example:
(define (helper x) ...)
(define-macro (foo bar)
`(,helper ,bar))
Assuming this macro is in the `(baz)' module, the direct translation of
this code would be:
(define (helper x) ...)
(define-macro (foo bar)
`((@@ (baz) helper) ,bar))
Of course, one could just use a hygienic macro instead:
(define-syntax foo
(syntax-rules ()
((_ bar) (helper bar))))
** Guile's psyntax now supports docstrings and internal definitions.
The following Scheme is not strictly legal:
(define (foo)
"bar"
(define (baz) ...)
(baz))
However its intent is fairly clear. Guile interprets "bar" to be the
docstring of `foo', and the definition of `baz' is still in definition
context.
** Macros need to be defined before their first use.
It used to be that with lazy memoization, this might work:
(define (foo x)
(ref x))
(define-macro (ref x) x)
(foo 1) => 1
But now, the body of `foo' is interpreted to mean a call to the toplevel
`ref' function, instead of a macro expansion. The solution is to define
macros before code that uses them.
** Functions needed by macros at expand-time need to be present at
expand-time.
For example, this code will work at the REPL:
(define (double-helper x) (* x x))
(define-macro (double-literal x) (double-helper x))
(double-literal 2) => 4
But it will not work when a file is compiled, because the definition of
`double-helper' is not present at expand-time. The solution is to wrap
the definition of `double-helper' in `eval-when':
(eval-when (load compile eval)
(define (double-helper x) (* x x)))
(define-macro (double-literal x) (double-helper x))
(double-literal 2) => 4
See the (currently missing) documentation for eval-when for more
information.
** New variable, %pre-modules-transformer
Need to document this one some more.
** Temporarily removed functions: `macroexpand', `macroexpand-1'
`macroexpand' will be added back before 2.0. It is unclear how to
implement `macroexpand-1' with syntax-case, though PLT Scheme does prove
that it is possible.
** New module: (rnrs bytevector)
See the R6RS for more information.
** New dependency: GNU libunistring.
FIXME bytevectors.
FIXME unistring.
more robust threading support.
syncase knows about @/@@
macros and hygiene and modules
eval-closure-module? what?
procedure-module / scm_procedure_module
guile-config info sitedir change -- 922d369
guile-config and pkg-config
(system xref), procedure-callers, procedure-callees, can work as
variables get redefined
getrlimit and setrlimit wrappers
FIXME: getrlimit crazy namespaces...
add method-formals
BUG? procedure-property 'arity on compiled procedures will be wrong
BUG: SCM_SNAME -> SCM_SUBR_NAME
(ice-9 session):
add-value-help-handler! remove-value-help-handler!
add-name-help-handler! remove-name-help-handler!
export module-commentary
procedure-arguments
procedure->memoizing-macro, procedure->syntax totally superdeprecated?
FIXME: update copyrights
ecmascript support?
new repl...
guile-tools compile, guile-tools disassemble (does that work?)
BUG: stack walks to see number of frames, then fills those frames.
sometimes those numbers differ, warning to console, a test case would be
nice.
FIXME: dance disassembly bug
srfi-18
<method> has formals, body slots; (make-procedure & procedure ?)
FIXME: rewrite while
removed (the-environment)
new function: scm_module_public_interface
BUG: help at guile prompt
new procedure, make-promise
* New modules (see the manual for details)
** `(srfi srfi-18)', multithreading support
** The `(ice-9 i18n)' module provides internationalization support
* Changes to the distribution
** Guile's license is now LGPLv3+
In other words the GNU Lesser General Public License, version 3 or
later (at the discretion of each person that chooses to redistribute
part of Guile).
* Changes to the stand-alone interpreter
* Changes to Scheme functions and syntax
** A new 'memoize-symbol evaluator trap has been added. This trap can
be used for efficiently implementing a Scheme code coverage.
@ -479,6 +457,33 @@ This slightly improves program startup times.
** New thread cancellation and thread cleanup API
See `cancel-thread', `set-thread-cleanup!', and `thread-cleanup'.
** Fix bad interaction between `false-if-exception' and stack-call.
Exceptions thrown by `false-if-exception' were erronously causing the
stack to be saved, causing later errors to show the incorrectly-saved
backtrace. This has been fixed.
** New global variables: %load-compiled-path, %load-compiled-extensions
These are analogous to %load-path and %load-extensions.
** New procedure, `make-promise'
`(make-promise (lambda () foo))' is equivalent to `(delay foo)'.
** New entry into %guile-build-info: `ccachedir'
** Fix bug in `module-bound?'.
`module-bound?' was returning true if a module did have a local
variable, but one that was unbound, but another imported module bound
the variable. This was an error, and was fixed.
** `(ice-9 syncase)' has been deprecated.
As syntax-case is available by default, importing `(ice-9 syncase)' has
no effect, and will trigger a deprecation warning.
* Changes to the C interface
** The GH interface (deprecated in version 1.6, 2001) was removed.
@ -491,6 +496,40 @@ application code.
** Functions for handling `scm_option' now no longer require an argument
indicating length of the `scm_t_option' array.
** scm_primitive_load_path has additional argument, exception_on_error
** New C function: scm_module_public_interface
This procedure corresponds to Scheme's `module-public-interface'.
** scm_stat has additional argument, exception_on_error
* Changes to the distribution
** Guile's license is now LGPLv3+
In other words the GNU Lesser General Public License, version 3 or
later (at the discretion of each person that chooses to redistribute
part of Guile).
** `guile-config' will be deprecated in favor of `pkg-config'
`guile-config' has been rewritten to get its information from
pkg-config, so this should be a transparent change. Note however that
guile.m4 has yet to be modified to call pkg-config instead of
guile-config.
** New installation directory: $(pkglibdir)/1.9/ccache
If $(libdir) is /usr/lib, for example, Guile will install its .go files
to /usr/lib/guile/1.9/ccache. These files are architecture-specific.
** New dependency: GNU libunistring.
See http://www.gnu.org/software/libunistring/. We hope to merge in
Unicode support in the next prerelease.
Changes in 1.8.7 (since 1.8.6)