+ $content = join '', @parts;
+ $content =~ s{ (?: [\n\s] | \\newline )+ $ }{}gx; # remove line breaks at the end of the text
+ $content =~ s{ ^ \s+ }{}gx; # remove white space at the start of the text
+ $content =~ s{ ^ ( \\newline \ )+ }{ _lb_to_space($1) }gxe; # convert line breaks at the start of the text to vertical space
+ $content =~ s{ ( \n\n+ ) ( \\newline \ )+ }{ $1 . _lb_to_space($2) }gxe; # convert line breaks at the start of a paragraph to vertical space
+ $content =~ s{ ( \\end\{ [^\}]+ \} \h* ) ( \\newline \ )+ }{ $1 . _lb_to_space($2) }gxe; # convert line breaks after LaTeX environments like lists to vertical space
+ $content =~ s{ ^ \h+ \\newline }{\\newline}gmx;
+ $content =~ s{ \n\n \h* \\newline \h* }{\n\n}gmx;
+
+ return $content;