It is possible to have multiple configurations for the same source at once. This is done using the out-of-source build support, also called VPATH building after the make variable used to support this feature.

Preparations

You only need to do this if you have earlier built a language in-source (the default). What you need to do is:

cd $GTLANG
make distclean

That is, cd into the language you want to reconfigure, and run the command make distclean. This command will not only delete the files you have built, but also all the generated Makefile’s and other generated build files. This is necessary to not confuse the build system.

Multiple configurations for a single language

The basic idea is to create a separate build directory for each configuration you need, and call the configure script from there. Here is one possible setup:

cd $GTLANG
mkdir build
cd build
mkdir xerox
cd xerox
../../configure
make
cd ..
mkdir hfst
cd hfst
../../configure --with-hfst --without-xfst
make

We just created two build directories — xerox and hfst — within a common build directory. Within each of them we called the configure script with the options needed to build for only the fst implementation specified. Everything should work as usual, including make check.

A setup like this can be used to have multiple configurations for the different build types: for spellers only, for dictionaries only, for oahpa, etc. Using this type of build setup, it is also easy to compare different build times, to compare the output of fst’s from different configurations, etc., since the resulting fst’s are in different build trees, and thus aren’t overwritten by the next make.

This can also be used to turn off some of the default targets, to speed up the compilation process as much as possible for the targets one wants. Here is an example of how to configure for building spellers, and spellers only:

cd $GTLANG
mkdir build
cd build
mkdir spellers
cd spellers
../../configure --with-hfst --without-xfst \
                --enable-spellers \
                --disable-analysers \
                --disable-generators \
                --disable-transcriptors
make

This will turn off compilation of the regular analysers and generators, and will for some languages save considerable compilation time. A similar strategy can of course be put to use for other specialised targets like MT. (There seems to be some shortcomings that should be fixed, vislcg3 files and generated documentation seems to be built always irrespective of configuration options.)

NB! When using out-of-source / VPATH building, the aliases usme, dsme, etc. do NOT work. This is because the aliases have hard-coded paths relative to $GTHOME/langs/. The plan is to replace the aliases with shell scripts, allowing us to test different locations for the fst files, and thus be able to handle such build setups in a more intelligent way.

Building many languages at once

It is possible to use this same strategy at the level of the $GTHOME/langs/ directory, with an additional option to only compile for a subset of the languages. To do this, do as follows:

$GTHOME/langs/
mkdir build
cd build
mkdir xerox
cd xerox
../../configure --enable-langs="sma sme smj sms smn yrk"
make

We have just configured a build tree that will only build the default Xerox fst’s, and only for the languages sma, sme, smj, sms, smn and yrk. One can also do make check to test that these languages (and these only) all pass the tests that we have defined.

To do the same for Hfst type fst’s, you specify the hfst option as usual:

$GTHOME/langs/build/
mkdir hfst
cd hfst
../../configure --enable-langs="sma sme smj sms smn yrk" --with-hfst --without-xfst
make

The --enable-langs option is understood by the configure script within $GTHOME/langs/, the rest of the options are passed on to the configure scripts in the language subdirectories.

Here is a configuration for compiling and testing all but a few languages:

 ../../configure --enable-langs="bxr chp ciw cor crk est fao fin fkv hdn ipk \
 izh kca kpv liv lut mdf mhr mns mrj myv nio nob olo ron rus sjd sma sme smj \
 smn sms som udm vep vro yrk"

The only languages left out are: kal, rup, sje, tat, tku, vot. Of these six languages kal builds fine, but takes an awful lot of time, whereas the rest have lexc errors that must be cleaned up. All other languages build just fine. This configuration only builds Xerox since it is so much faster, but this makes for a nice check that the code is syntactically valid.

NB! During configuration, the configuration script will traverse all language directories and it looks like it will build all of them. But when it comes to build time, only the specified languages will actually be built.

Using VPATH builds in the langs/ directory is a much more flexible solution than using a shell script to build all languages, as it allows as many configurations as you want, with different language combinations, different fst technologies, different target options, etc. To keep track of all the different build configurations, it is probably wise to give the different build directories descriptive names reflecting the intended/actual configuration used.

Restrictions on VPATH building

There is really only one restriction:

You can not combine VPATH building with in-source building.

That is, you can’t have both a separate build/ directory and build directly within your $GTLANG/ directory. This means that as long as we rely on the aliases mentioned above, you can’t have both working aliases and VPATH building.