2.4.5.1 Compiling a single library

This library compilation strategy is implemented by a proper execution mode of Vicare enabled by the command line option --compile-library of vicare. In this mode:

• The compile–time library locator is selected, Compile–time libraries search.
• A R6RS library is loaded from an explicitly selected source file, compiled, and possibly invoked and visited.
• It is assumed that all the library’s dependency libraries are available in binary format.
• The loaded library is serialised to a FASL file in an explicitly selected output file or in the selected compiled-library-build-directory.

Let’s say we have the libraries:

(alpha beta (1 0))
(alpha gamma (1 2))

in the files:

$(srcdir)/lib/alpha/beta.sls
$(srcdir)/lib/alpha/gamma.sls

we want to compile them to:

$(builddir)/lib/alpha/beta.fasl
$(builddir)/lib/alpha/gamma.fasl

and (alpha gamma (1 2)) imports (alpha beta (1 0)). We have multiple options:

• We explicitly execute (in the correct order) the commands that compile one library at a time, explicitly selecting the source and binary file pathnames. First, to compile (alpha beta (1 0)), we do:

  vicare \
    --compile-library $(srcdir)/lib/alpha/beta.sls \
    --output $(builddir)/lib/alpha/beta.fasl
  

  then, to compile (alpha gamma (1 2)), we do:

  vicare \
    --build-directory $(builddir)/lib \
    --compile-library $(srcdir)/lib/alpha/gamma.sls \
    --output $(builddir)/lib/alpha/gamma.fasl
  

  when the option --compile-library is used and no library locator is explicitly selected with the option --library-locator: the compile-time library locator is automatically selected.

• We explicitly execute (in the correct order) the commands that compile one library at a time, explicitly selecting the build directory. First, to compile (alpha beta (1 0)), we do:

  vicare \
    --build-directory $(builddir)/lib \
    --compile-library $(srcdir)/lib/alpha/beta.sls
  

  then, to compile (alpha gamma (1 2)), we do:

  vicare \
    --build-directory $(builddir)/lib \
    --compile-library $(srcdir)/lib/alpha/gamma.sls
  

This compilation strategy is useful when compiling a “big” number of libraries with a traditional Makefile:

• It allows compiling only libraries for which the source is newer than the binary.
• It allows running the compilation commands in parallel when possible, using, for example, the -j option of GNU Make.

To use this strategy effectively we need to write all the compilation commands, correctly tracking the dependencies; this is tedious, but there are ways to automatically generate the needed commands.