print "Latexmk rc file for using precompiled headers.\n",
"John Collins. V. 1.3. 3 Jan 2024.\n";
# John Collins jcc8 at psu dot edu
# To implement precompilation of preamble by the package mylatexformat.
# See the documentation for the package mylatexformat for more information.
# Overall strategy:
# 1. At start of each run of *latex rule, copy (relevant part of) preamble
# from the primary .tex file to a file with extension .hdr.
# 2. The base name of the header file has -latex, or -pdflatex, etc
# appended to it. That provides a flag as to which program is to be
# used to make the .fmt file, and what program can use the .fmt file.
# 2. A cus-dep is defined to make a .fmt file from the corresponding .hdr
# file. It uses mylatexformat, and whichever of the -latex, -pdflatex,
# etc strings appears at the end of its base name indicates which
# program to use to create it. (The -ini option is given to the
# program to indicate that a .fmt file is to be made.)
# 4. Compilation of document: use .fmt file if it exists.
# If not, inject a message into the log file, to indicate that the .fmt
# is missing. After the analysis of the results of the compilationi,
# latexmk takes this as an indication that it should try to make the
# .fmt file.
#
# Note that on an initial round of compilation, before the format file has
# been created, latexmk will do one round of compilation without a
# precompiled preamble. After that latexmk creates the format file for the
# precompiled header. Some trickery could be used to get the format file
# to be made first, but since this is a one-time-only issue, it's simpler
# not to do the trickery.
#
# Restriction: Doesn't work with spaces and/or non-ASCII characters in
# name of .tex file.
# STILL TO DO:
#
# 1. Get full dependency information for the step for making the format.
# Ideally that needs support from latexmk, so as to use its
# already existing tools. (Complication: the usual way in which latexmk
# determines dependencies from a run of a *latex type program assumes
# that a correct run always generates an .aux file. That's not the case
# for "pdflatex -ini" etc.
# I've done a sufficient job, I think, by using the -recorder option,
# analyzing the resulting .fls file and using latexmk's documented
# rdb_set_source subroutine.
# 2. On make of .fmt file, need ideally to use jobname = $root, to avoid
# problems listed in
# https://tex.stackexchange.com/questions/19403/tikzs-externalization-and-mylatex
# Then I would need to do some renaming; perhaps save fls and log files from
# main run, compile the header, rename the fls, log and fmt files from this
# run, and finally, put the original fls and log files in place.
# Better, perhaps: Use subdirectories of auxdir, e.g., named fmt-latex,
# fmt-pdflatex, etc, to contain .fmt file (and .hdr file), along with
# suitable setting of search path (in variable TEXFORMATS).
# General settings
$out_dir = 'output';
$aux_dir = 'auxdir';
$emulate_aux = 1; # Avoid any problems with TeXLive, which doesn't
# natively support different aux and out directories.
$show_time = 1; # Show diagnostics on timings, so as to make visible
# time savings due to use of preamble.
# Sub-second sleep time will work in latexmk v. 4.82 upwards.
# That gives excellent responsiveness when preview-continuous mode is used,
# and helps to enhance any significant gain in compilation time from the
# use of a precompiled preamble.
$sleep_time = 0.05;
$pdf_mode = 1; # Use pdflatex. Note that xelatex and lualatex don't work
# with precompiled preambles.
# Configuration for precompiled preamble:
$make_fmt = '%C %O -ini -output-directory=%V -jobname=%B "&%C" mylatexformat.ltx %S';
# I only arrange to use latex and pdflatex with precompiled preambles.
# None of lualatex, xelatex, and hilatex can use precompiled headers (from
# tests on 22 Dec 2023). Each had different trouble, and this is a known
# problem.
# But things did work for latex and pdflatex.
# Therefore only set things up for latex and pdflatex.
foreach my $engine ( 'latex', 'pdflatex' ) {
say "Setting rules for $engine";
${$engine} = "internal mylatex %R $engine %O %S";
push @generated_exts, "%R-$engine.*";
}
add_cus_dep( 'hdr', 'fmt', 0, make_fmt_cus_dep );
push @generated_exts, '%R-*.hdr', '%R-*.fmt';
#=================================================
sub make_fmt_cus_dep {
my $path_base = $_[0];
my ($base, $path) = fileparse($path_base);
my $source = "$path_base.hdr";
my $dest = "$path_base.fmt";
my $fls = "$path_base.fls";
my $engine = 'pdflatex';
if ( $base =~ /-([^-]+)$/ ) {
$engine = $1;
}
my $cmd = $make_fmt;
$cmd =~ s/%C/$engine/g;
my $options = '-recorder';
if ($silent) { $options .= ' -interaction=batchmode'; }
my $ret = Run_subst( $cmd, 2, $options, $source, $dest, $base );
my @source_files = get_fls_inputs( $fls );
if (@source_files) { rdb_set_source( $rule, @source_files ); }
else { warn "Could not determine source files for '$rule'\n"; }
return $ret;
}
#=================================================
sub make_hdrA {
use strict;
my ($source, $dest) = @_;
my $h_in = undef;
my $h_out = undef;
if ( ! open( $h_in, "<", $source ) ) {
print "make_header could not read source file '$source'\n";
return 1;
}
if (! open( $h_out, ">", $dest ) ) {
print "make_header could not write header file '$dest'\n";
return 2;
}
while (<$h_in>) {
if ( /^\s*\\begin\s*{document}/
|| /^\s*\\endofdump/
|| /^\s*\\csname\s+endofdump\\endcsname/
)
{ last; }
print $h_out $_;
}
print $h_out "\\endofdump\n";
close $h_out;
close $h_in;
return 0;
}
#=================================================
sub mylatex {
# Arguments are:
# 1. base name of the fmt file
# 2. the compilation program
# then the arguments to be
use strict;
our ($aux_dir1, $out_dir1, $emulate_aux, $Pbase, $Psource );
my ($fmt_base, $engine, @args) = @_;
$fmt_base .= "-$engine";
my $source = $$Psource;
my $ret = 0;
my $fmt_file = "$aux_dir1$fmt_base.fmt";
my $hdr_file = "$aux_dir1$fmt_base.hdr";
if ( make_hdrA( $source, $hdr_file ) > 0 ) {
die "I'm stopping, since I could not make '$hdr_file' from '$source'.\n";
}
# Location of .fls file after running engine, before any fudge to
# emulate aux dir:
my $fls_file = ($emulate_aux ? $aux_dir1 : $out_dir1 ) . "$$Pbase.fls";
my $log_file = "$aux_dir1$$Pbase.log";
if ( -e $fmt_file ) {
@args = ("-fmt=$fmt_base", @args);
}
else {
print "Format file '$fmt_file' does not exist. I'll run without it.\n";
}
my @cmd = ($engine, @args);
print "Running '@cmd'\n";
$ret = system @cmd;
# Add lines to fls file to add dependency information:
# (a) that a hdr file is generated.
# (b) dependency on fls file.
# Earlier I thought I needed to force a dependence on fls file.
# (22 Dec 2023) I don't remember why, so I'll leave that in.
append( $fls_file,
"INPUT $fls_file\n".
"OUTPUT $hdr_file\n"
);
# Ensure latexmk knows that the .fmt file needs to be made if it
# doesn't yet exist:
if ( !-e $fmt_file ) { append( $log_file, "No file $fmt_file.\n" ); }
return $ret;
}
#=================================================
sub append {
use strict;
my ($file, $string) = @_;
if ( !-e $file ) { return 1; }
open( my $fh, ">>", $file )
or die "Cannot append to '$file'\n $_";
print $fh $string;
close $fh;
return 0;
}
#=================================================
sub get_fls_inputs {
my $fls_file = shift;
my %inputs = ();
my $fh = undef;
if ( ! open( $fh, '<', $fls_file ) ) {
warn "Cannot read '$fls_file':\n$!";
return ();
}
while (my $line = <$fh>) {
if ( $line =~ /^INPUT\s+(.+)\s*$/ ) {
my $file = $1;
$inputs{$file} = 1;
}
}
close $fh;
return keys %inputs;
}
#=================================================