NAME

       vlna - adds tilde after each non-syllabic preposition

USAGE

       vlna [options] [filenames]

PREFACE

       There  exists  a  special  Czech  and Slovak typographical rule: you cannot leave the non-
       syllabic preposition on the end of one line and continue writing text on  next  line.  For
       example, you cannot write down the text "v lese" (in a forest) like "v<new-line>lese". The
       program vlna adds the asciitilde between such preposition and the next  word  and  removes
       the  space(s) in this place.  It means, the program converts "v lese" to "v~lese". You can
       use this program as a preporcessor before TeXing. Moreower, you can set  another  sequence
       to store instead asciitilte (see the -x option).

DESCRIPTION

       The  program  vlna  processes  one  or  more files, searches the non-syllabic prepositions
       followed by space(s) in these files and converts this/these  space(s)  to  asciitilde  for
       each such occurrence.

       In  the processed file, the activity of the program can be blocked by %~- sequence and the
       activity can be restored again by the %~+ sequence. These sequences can include spaces, it
       means that % ~- is a correct sequence too.

       The  rule  to recognize a preposition follows: The arbitrary number of opening parentheses
       can be written before the preposition and before these (optional) parentheses must be  the
       space,  tabelator or new-line. The preposition itself is one-letter word, the letters have
       to be from this set: {KkSsVvZzOoUuAI}. See the -v option if you want to change this set of
       letters.  From  version 1.2, the TeX sequence can be written before preposition and before
       the brace. Example: "<new-line>([V lese" is converted  to  "<new-line>([V~lese".   Another
       example: "\uv{V lese}" is converted to "\uv{V~lese}".

       One  or  more  blank-spaces  have  to  be included after preposition before next word. The
       blank-space means space or  tabelator.   One  <new-line>  can  be  here  too.   All  these
       characters  are  removed and replaced by asciitilde (or by another string, see -x option).
       If <new-line> is deleted, another <new-line> is created  before  preposition  (and  before
       optional  parentheses)  in  order to the number of lines is kept unchanged.  Example: "...
       V<new-line><tabelator>lese" is converted to "...<new-line>V~lese".

       The program checks the consintence of TeX's math environments (if -m option  isn't  used).
       For  example  the "$...$$...$" sequence (it means the display mode switch inside the text-
       math mode) generates a warning. Empty line inside display mode generates a warning too and
       the  program  processes next text like in normal (non-math) mode. The existence of the "$"
       inside display mode are accepted because the constructions like $$..\hbox{..$..$}..$$  are
       allowed and common.

       The  consistence of verbatim mode is checked on the end of the file.  If the file ends but
       the verbatim mode does not end the warning is printed.  This behavior can be switched  off
       by -n or -w options.

       The program suppresses the tilde changing after letters like prepositions but they are not
       prepositions because the \TeX or \LaTeX sequence precedes.  Example:  "vlastnosti  \TeX  u
       jsou"  is  not  converted to "vlastnosti \TeX u~jsou", because this text is printed (after
       TeX processing) like "vlastnosti  TeXu  jsou".  The  letter  "u"  is  a  suffix  here,  no
       preposition.

OPTIONS

       The options are optional and can be written in arbitrarty order separated by space.

       -f     Filter. The [filenames] are treated as follows:

              vlna -f filename1 filename2
                  Input is filename1, output is filename2.

              vlna -f filename1
                  Input is filename1, output is stdout.

              vlna -f
                  Input is stdin, output is stdout.

              vlna filename1 [filename2 [filename3 ...]]
                  If the -f option is omitted then each file is processed independently and it is
                  re-written.

       -s     The silent mode. No messages, warnings, statistics are printed.  Only errors  which
              terminates  the  program  untimely  are printed.  If this parameter is omitted then
              banner, warnings and statistics are printed to stderr.

       -r     Do not create the backups. The option -r is irrelevant if the -f option is used. If
              the  -f  and  -r  options  aren't used then each re-written file is stored with its
              original contents to a backup file  (the  name  of  backup  file  is  the  same  as
              filename, only the tilde is used instead of the last character).

       -v characters
              The  set  of  characters  treated  as non-syllabic prepositions is declared by this
              option. Default:  -v KkSsVvZzOoUuAI.   The  space  between  -v  and  characters  is
              required.

       -x code
              The  code  is  a  string  written  in  hexadecimal  notation  (even  hexa digits is
              required). This string will be saved after prepositions instead asciitilde which is
              default.   The  example:  -x  C2A0  two  bytes  are  stored after each non-syllabic
              preposition, first byte has C2 code and second byte has A0 code. This example means
              that  NO-BREAK  SPACE  in  UTF8  encoding will be used after prepositions.  Another
              example: -x 00A0 the  NO-BREAK  SPACE  in  UTF16  encoding.   Another  example:  -x
              48454C4C4F  the  string  HELLO  will  be  used.   The  space between -x and code is
              required.

       -m     The math-modes ($...$  and  $$...$$)  are  ignored.   It  means  that  non-syllabic
              prepositions is searched in math-mode too.  Default (without -m option): no changes
              in math modes are done because (for example)  "v"  is  variable  in  math-mode,  no
              preposition.

       -n     The  verbatim mode (\verb<char>...<char>, \begtt...\endtt) is ignored, it means the
              program can do a changes in verbatim environment.  Default (without -n option):  no
              changes in verbatim mode are done.

       -l     The   LaTeX   mode.  The  following  environments  are  treated  as  display  mode:
              \begin{display}...\end{display}  and  \begin{equation}...\end{equation}   and   the
              following       environment       is       treated      as      verbatim      mode:
              \begin{verbatim}...\end{verbatim}.

       -w     The web mode (Knuth's web, no  www:-).  The  following  sequences  are  treated  as
              verbatim: @<, @d...@*, @space or @>|.  It means program code is unchanged in *.w or
              *.web files, only web-comments are processed.

EXAMPLES

       vlna -m -n -s -r file
              The program has a behavior similar to the old vlnka program.

       vlna *.tex
              All files with .tex suffix in current directory will  be  processed  (and  possibly
              changed). (The "*" is UNIX-shell feautre).

       vlna -f file > /dev/null
              Only  the consistence checking of math and verbatim modes is processed.  No changes
              are done.

AUTHORS

       Petr Olsak <olsak@math.feld.cvut.cz>.  Man page (Czech original) and Makefile  is  created
       by Rulolf Cejka

                                          August 30 2022                                  VLNA(1)