=head1 NAME

makepp_release_notes -- Major changes in each version of makepp

=for vc $Id: makepp_release_notes.pod,v 1.53 2008/06/01 22:01:17 pfeiffer Exp $

=head1 DESCRIPTION

=head2 Version 1.50 (under development)

=over 4

=item *

Makepp will now also look for options in files called F<.makepprc>.  The
option C<-A> or C<--args-file> is now consistently available on all commands.

=item *

The environment variable MAKEPP_CASE_SENSITIVE_FILENAMES supercedes the
options --case-sensitive-filenames and --no-case-sensitive-filenames.

=item *

New variable $/ for portable directory separator.  Lots of Windows fixes,
including C<-j> (parallel builds) for Cygwin and MinGW and smart recursive
builds on Cygwin.

=item *

Makepp has become noticeably faster.

=item *

Also install abbreviations consisting of 'mpp' plus the first letter of every
following word, e.g. 'mppc' for L<makeppclean|makeppclean>.

=item *

New L<makepplog, mppl|makepplog> utility to see the log data readably, needed
due to a changed file format.  New L<makeppgraph, mppg|makeppgraph> utility to
graphically analyze dependencies, includes and partially the reasons for a
rebuild.  New L<makeppinfo, mppi|makeppinfo> utility to see somewhat
cryptically what makepp knows about some file.

=item *

All utilities now also query an environment variable for presetting options.
Each one is called like the utility in upper case, with FLAGS added,
e.g. C<$MAKEPPCLEANFLAGS> or C<$MAKEPPLOGFLAGS>.

=item *

New `:build_check only_action' for commands that don't depend on the contents
of their dependencies, like symlink creation, where it is used automatically.

=item *

Removed C<--keep-repository-links> option, the behaviour of which is now the
default.

=item *

Removed C<--norc-substitution> and C<--percent-subdirs> and
C<$(rc_substitution)> and C<percent_subdirs>.  They are now to be given
anywhere from target specific assignment to command line or environment vars
C<makepp_simple_concatenation> and C<makepp_percent_subdirs>.

=item *

New action syntax C<&perl_function 'arg 1' arg2 ...> and
C<&external-perl-script 'arg 1' arg2 ...>  New Perl function C<run>.

There are the following L<builtin commands|makepp_builtins>: C<&chmod>,
C<&cp>, C<&cut>, C<&echo>, C<&expr>, C<&grep>, C<&install>, C<&ln>, C<&mkdir>,
C<&mv>, C<&perl>, C<&preprocess>, C<&printf>, C<&rm>, C<&sed>, C<&sort>,
C<&template>, C<&touch>, C<&uninstall>, C<&uniq> and C<&yes>, which can
replace Unix commands of the same name, and more or less also the following:
C<awk>, C<chgrp>, C<chown>, C<head>, C<m4>, C<rmdir>, C<tail> and C<tr>.  They
are also available L<stand-alone|makeppbuiltin> from the Shell.  They can also
be used as functions, e.g. C<$(&cat file)>, or as
L<statements|makepp_statements/Commands>, or standalone.

Note that, unlike earlier CVS versions, C<&cut -f>, C<&grep -v> and C<&sort
-r> now behave as in Unix.  Note that in earlier CVS versions of C<&template>
C<@@> was processed before C<@>, but now lines are consistently handled front
to back.

=item *

Added a C<global> statement for sharing variables accross makefiles.  The
assignment variant of C<export> now works like a normal assignmant, so you may
have to change to C<:=>.  Added the C<override> modifier to assignments.  The
C<define var :=> statement now optionally allows specifying the kind of
assignment.  And the forms with immediate evaluation retain the newlines in
C<$(shell ...)> or C<$(&command)>.  There are new assignment operators C<&=>
for prepending, and C<;=> which is a C<=> when set, but automatically turns
into a C<:=> when first used.

=item *

Short command line options may now be grouped in the Unix way, so C<-k -j 4>
may be given as C<-kj4>.  In all long options the dash between words may now
consistently be omitted or replaced with an underscore, so that C<--no-log>
can be C<--nolog> or C<--no_log>.  Unknown options now cause an error.

=item *

A makefile is now also found if it is called C<Makeppfile.mk>.

=item *

There are two new possible filenames for makefiles: C<RootMakeppfile> or
equivalently C<RootMakeppfile.mk>.  The presence of either of these gives your
build tree a formal root, accesible through the new variable C<$(ROOT)>.  The
advantage is that this file is always loaded first, if present, allowing you
to more easily create a build system where makepp can be called from anywhere,
without telling it which makefile to start at.

The root of the file system is then automatically marked for C<--dont-build>,
so that makepp doesn't go messing into other directories you include or use
libs from, just because they happen to have a Makefile or sources.

Usually this means that the root of your build system gets marked for
C<--do-build>.  If, however, you say C<--do-build> for something under your
build system root, which doesn't inherit C<--dont-build>, then instead your
build system root gets marked for C<--dont-build>.

=item *

New option C<--stop-after-loading> (or C<--stop>) gives makepp a headstart
while you're still editing.

=item *

Removed command C<makeppclient> since we never managed to let builds start
significantly faster.  The option C<--stop-after-loading> is more beneficial.

=item *

Interface definition files for SWIG (.i files) are now scanned for
includes.  Makepp now understands swig invocations.  (SWIG stands for
Simplified Wrapper and Interface Generator.  It automatically generates
all the wrapper functions to link your C or C++ code to a variety of
other languages such as perl, python, tcl, ruby, ocaml, C#, etc.  See
http://www.swig.org.)

=item *

Gnu Emacs 22 now has a standard makefile-makepp-mode, which is the default
when visiting F<Makeppfile>.

=item *

$[VARIABLE] or $[function ...] is evaluated when reading a makefile line, so
the variable may contain makepp syntax.

=item *

$( ...) is now always a list in rc-style substitution, so that C<-I$(
$(DIRLIST))> will leave no lonely option when DIRLIST is empty.

=item *

You can now double-paren functions and multi-line lists, allowing things like
S<C<$((perl if( $a < 5 ) { ... }))>>.

=item *

New C<c_compilation_md5> signature, which also allows adding whitespace where
there was none and inversely.  It also ignores whitespace and comments after
the last token.  This is useful for preventing a useless rebuild if your VC
adds lines at a C<$>C<Log$> tag when checking in.

=item *

New scanner C<esqlc_compilation> for embedded SQL C.  You must supply the
rules, however.

=item *

Implement C<$?> exactly as GNU make does.  New long name C<$(changed_inputs)>
for it.

=item *

Implement C<$(error ...)> and C<$(warning ...)> as in GNU make.

=item *

New method C<: build_check ignore_action> to ignore changes to the action
string.

=item *

New statements C<ifperl>, C<ifmakeperl>, C<iftrue>, C<ifntrue>, C<ifsys> and C<ifnsys>.

=item *

Conditionals C<ifxxx> may now be grouped with C<and> and C<or>.  When written
on the same line after C<else>, they create a branch of the same statement,
rather than requiring nesting.

=item *

New options C<--rm-stale>, C<--sandbox> and C<--dont-read>, for sandbox
control when running multiple concurrent (possibly distributed) makepp
commands.

=item *

Added support for dependencies on environment variables, using the
C<:env> rule option.

=item *

Various signal handling fixes.

=item *

New command C<makeppclean> that efficiently removes generated files
without loading makefiles.

=item *

Ported to MinGW.

=item *

Experimental new build caches, to cache files that are identical.  This means
that if you change a file and revert, then you can have makepp drop back to
the immediately preceding .o file without rebuilding.  Or you can share builds
of identical files between separate source trees.  This feature is still
experimental and the interface is not yet final.  Newly added grouping of
build caches.

=back

=head2 Version 1.40 (December 2004)

Thanks to Anders Johnson and Daniel Pfeiffer for major contributions of
code to this release.

=over 4

=item *

Too many bug fixes to list individually.  Probably the most salient
fixes are to make it work significantly more reliably on cygwin, but
there were also fixes to variable expansion, scanning, repositories,
etc.

=item *

Rewritten command parser and file scanner architecture so that it is
more easily extensible.  Makepp now supports Verilog (a language used
for chip design) in addition to C++ and Fortran.  It should be
relatively straightforward to support additional languages.  I<(Anders
Johnson)>

=item *

New command C<makeppclient> that lets builds start faster.  I<(Daniel
Pfeiffer)>

=item *

If you have Perl 5.6.0 or higher, HTML documentation now comes with the new
working camel logo and syntax highlighting in the examples.
I<(Daniel Pfeiffer)>

=item *

Numerous corrections and improvements to the documentation.  I<(Mostly
Anders Johnson)>

=item *

Support for GNU make's C<define> statement to define multi-line variable
values.

=item *

$(PWD) and $(CURDIR) now work as in GNU make.

=item *

New C<--keep-repository-links> option to prevent makepp from deleting
all the soft links it creates when making repositories.

=item *

New C<--assume-old>, C<--assume-new>, and C<--dont-build> options, and
support for the C<-n> option.

=item *

Support for double colon rules has slightly improved, so that we can
handle makefiles produced by MakeMaker without much trouble.

=item *

Added syntax for perfoming Perl code as a statement and in rules C<perl { ...
}> or C<makeperl { ...  }>.  Added functions for evaluating Perl statements
C<$(perl ... )> or C<$(makeperl ... )>.  Added statement C<makesub { ... }>.
I<(Daniel Pfeiffer)>

=item *

Short options can now be directly followed by argument as in -j4.  Documented
options --jobs, --keep-going, --makefile, --what-if, --assume-new, --new-file,
--assume-old & --old-file are now really accepted.
I<(Daniel Pfeiffer)>

=back

=head2 Version 1.19 (July 2003)

Special thanks to Matthew Lovell and Chris van Engelen for lots of suggestions
and tracking down problems in the code.

=over 4

=item *

Documentation was reorganized so that man pages as well as HTML pages can be
produced, and a cookbook/FAQ was added (see L<makepp_cookbook>).

=item *

A "configure" script was added so installation is more like other software
products from the user point of view.

=item *

The S<C<$(origin )>> function from GNU make is now supported.

=item *

L<Target-specific variables|makepp_variables/Target-specific
assignments> are now supported as in GNU make, except that they do not
propagate their values to dependencies.

=item *

New functions S<C<$(find_upwards )>> and S<C<$(relative_filename )>>
(contributed by Matthew Lovell) and S<C<$(relative_to )>>.

=item *

In compilation commands, S<C<-I dir>> and S<C<-L dir>> are now supported
and work just like C<-Idir> and C<-Ldir>.

=item *

Recompilation of C files will now occur if a multi-line comment was
inserted, or if the line numbering changed in any way.  Previously it
ignored newlines in computing the checksum, which meant that a change
that affected debugger info might not force a recompilation.

=item *

A bug in S<C<$(shell )>> which caused it to return a null string occasionally
(especially when the system was heavily loaded) was fixed.

=item *

Unreadable files or directories suppress importing from repositories but are
not matched by wildcards.

=item *

A few other minor bugs were fixed.

=back

=head2 Version 1.18

The most important change was support for the Cygwin build environment.
You can now run makepp with the Cygwin version of perl; I do not think
it will work properly with the native windows version of perl yet.

A few other bug fixes went into this release.

=head2 Version 1.10

The most important change in this version is that makepp can accept a
vastly larger number of makefiles without any command line options
because of some changes to the implementation of recursive make.  There
are a few minor improvements in the GNU make compatibility, and a slight
improvement in memory usage.


There are several user visible changes:

=over 4

=item *

C<c_compilation_md5> is now the default signature method.  This means
that by default, makepp won't recompile C/C++ modules if only whitespace
or comments have changed.

=item *

A new signature method C<md5> has been added, which runs an MD5 checksum
on the file's contents.  This is not enabled by default; makepp still
uses its original method (C<exact_match>) for any files other than C/C++
source files.

=back

Because of these changes, makepp will recompile everything the first
time you run it.

=head2 Version 1.05

In addition to bug-fixes, this version has one user-visible change.  The
C<--norc-substitution> command line option was introduced to allow
compatible handling of whitespace in makefiles.

=head2 Version 0.99

In addition to numerous bug fixes, this version has several user-visible
changes:

=over 4

=item *

Multiple targets for a rule are now treated in a way which is more
compatible with old makefiles.  Makepp has a heuristic algorithm for
guessing whether the rule is supposed to build all targets at once or
whether the rule needs to be invoked multiple times.  I do not think
this will break any existing makefiles, but it should allow makepp to
work with many more makefiles designed for unix make.

=item *

The C<--traditional-recursive-make> option can be used for legacy
makefiles which use recursive invocations of make in a way that didn't
work with makepp's default implementation.

=item *

Repositories now work with libtool.

=item *

Variable settings are now allowed with the C<load_makefile> statement
and with recursive make.

=back

=head2 Version 0.95

This version has several user-visible changes:

=over 4

=item *

A tutorial on writing makefiles for makepp has been added.

=item *

GNU make style conditionals (ifeq/ifneq/ifdef/ifndef) are now
supported, as is the S<C<$(if )>> function.

=item *

By default, the C<%> wildcard now matches only files within a directory;
C<%.c> is now equivalent to C<*.c>, not C<**/*.c>.  The reason for this
change was that rules almost never need to use the more complicated
wildcard, and it often caused unnecessary directories to be searched.
You can get the old behavior by specifying C<--percent-subdirs> on the
command line.  (I'm curious how people feel about this change.  Please
let me know if you have good reasons for it being one way or the other.)

=item *

By default, makefiles from any directory that contains a dependency, or
that is searched by a wildcard, are loaded automatically.  Usually this
means you don't need any C<load_makefile> statements at all.  If this
causes you problems, you can turn off implicit loading of makefiles by
adding C<--no-implicit-load> to the command line.  (I'm curious whether
people like or dislike implicit loading of makefiles.)

=item *

A target may now be declared phony on the same line that defines the
target by using the new S<C<$(phony )>> function, like this:

    $(phony all): program_1 program_2

The S<C<$(phony )>> function simply returns its
arguments, but marks them as phony targets.  You can still use
the older syntax that looks like this:

    all: program_1 program_2

    .PHONY: all


The S<C<$(phony )>> function is an attempt to improve the readability of
makefiles.  I'd welcome other suggestions, as I'm still not entirely
happy with the syntax.

=back

=head2 Version 0.90

In order to support features like parallel make, most of the internals
had to be reorganized or rewritten.  The result is much cleaner and
hopefully more reliable.

Bugs too numerous to mention have been fixed.  In order to help ensure
reliability, a test suite has been developed.  It doesn't test
absolutely everything yet, but it does test most things, and I hope to
make it more extensive in the future.  You can run it by typing C<makepp
test> in the makepp distribution directory.  If an unmodified makepp
fails the test suite, please let me know so I can fix it.


There are many new features:

=over 4

=item *

Repositories are now supported.

=item *

It is now possible to specify different methods for calculating and
comparing file signatures.  For example, you can use an MD5 checksum
ignoring comments and whitespace, or you can require merely that the
target be newer than the dependencies (the method that the traditional
make uses).

=item *

Makefiles are only rebuilt if they are older than their dependencies; a
different signature method is used in this special case.

=item *

Parallel builds are now supported, though this is still an experimental
feature.  See the C<-j> option.

=item *

It is now possible to write your own functions.  See the C<sub>
statement and L<makepp_extending> for details.

=item *

Filenames with characters like colon or space are now
supported with a new quoting syntax.

=item *

Synonymous, less cryptic names for automatic variables have been
introduced to encourage more readable makefiles.

=item *

Makepp now remembers the architecture of the machine
you built on, and rebuilds if the architecture is different.

=item *

Directories can now be targets or dependencies; a previous restriction
that all directories had to exist before the start of the build has been
lifted.

=item *

Makepp now writes a log file called C<.makepp_log> explaining why it
rebuilt everything.  This is extremely useful for debugging.

=item *

The usual C<-k> option for continuing to build even when an error occurs
is now supported.

=item *

The documentation has been reorganized and extended.

=back

There are also (unfortunately) a few incompatibilities with
previous versions:

=over 4

=item *

The file format for storing information about the last build has
changed.  Thus makepp will insist on rebuilding everything the first
time you run the new version.

=item *

load_makefile no longer supports targets or variable settings.  It now
supports loading a list of makefiles rather than just one, so the C<-F>
switch is now unnecessary (and no longer documented).

=item *

Recursive make now ignores variable settings on the command
line.  This is necessary to load makefiles in a consistent way.

=item *

C<$(INFERRED_OBJS)> is no longer supported (since it was not a
well-designed interface anyway).  Use the newer S<C<$(infer_objects )>>
function instead.

=item *

C<$_> is no longer supported.  Use C<$(foreach)> instead.

=item *

A few seldom used GNU make options such as C<-s>, C<-n>, and C<-q> are
no longer supported due to internal architecture changes.  C<-n> will
probably be supported again in future releases.

=item *

A man page is no longer provided since the documentation is no longer
written in the perl pod format.  Use the HTML documentation instead.

=item *

The automatic clean target is no longer supported.  A better
way to do it is with C<$(only_targets)>.

=back
