GOSH Documentation

                           Norman Feske


Introduction
############

; This document demonstrates GOSH and all its implemented features.
;
; BTW: Comments start with ';' and are ignored by GOSH

GOSH is a tool for converting plain ASCII text to LaTeX and other document
formats. Its main design criteria was to use a syntax that is perfectly
readable as plain ASCII text and the support of different target formats.
The source files of GOSH have a very simple syntax that is similar to the
usenet style. Everyone, who ever wrote a mail using an plain ASCII editor
will be able to write GOSH texts.
; Actually, the file you are reading right now is a GOSH text file.
GOSH supports multiple target formats by different backends, which are
available as separate files. By now, there exists the built-in LaTeX backend,
a simple HTML backend and a man-page backend.

Originally, GOSH was meant as an alternative to writing LaTeX files by hand.
In the meanwhile I do all kind of textual work, papers, documentation,
websites and slides using GOSH. As it is a big help for myself, it might be
useful for other people, too. Anyhow, this is an early version of GOSH.
Its features and usage may change in the future.


How to get GOSH?
################

:GOSH is available at GitHub:

  [https://github.com/nfeske/gosh]


Licence
#######

GOSH and its backends are released under the terms of the GNU General Public
Licence. For more information about the GNU General Public Licence visit the
official GNU website [http://www.gnu.org/licenses].


Usage
#####

GOSH is written in the script language 'Tcl/Tk'. Make sure that you have
'Tcl/Tk' installed on your computer before trying out GOSH. Just check,
if you have a program called 'tclsh'.

GOSH must be called with the source text file as argument and uses standard
output for printing its result. For example. a pdf-file of the this text
can be created via:

! > gosh gosh.txt > gosh.tex
! > pdflatex gosh.tex

In this example, GOSH generates LaTeX output that is stored in the file
'gosh.tex'. This file is then used as input file for 'pdflatex'.

A HTML-version of the text can be created by using the HTML-backend:

! > gosh --style html.gosh gosh.txt > gosh.html

The backend to use is specified via the '--style' argument. The 'html.gosh'
file contains the rules of how to produce the HTML output.


Text style
##########

Paragraphs are separated from each other be leaving an empty line between
them.

If you want to insert verbatim text passages (with monospaced font) - for
example source codes, you can mark these lines with a '!' at the beginning
of line. For example:

! void main(int argc, char **argv) {
!   return 0;
! }


Items, Enumations and Descriptions
==================================

GOSH supports items by a leading '*', followed by a space:
* This is an item.
* Items can span over multiple lines.
  Each subsequent line must be indented by two spaces.

  Even paragraphs within items are possible.
  * Nested items are supported as well.

  * Items can be separated by empty lines to make them
    better readable in the GOSH text.

Enumerations are marked by a leading '#' character and behave
like items.

# They can be nested.
# They can span multiple lines.
# They can contain multiple paragraphs.

GOSH supports descriptions in a very similar way as items and enumerations.
The text to describe is enclosed by colons (':'), followed by the description
text:

:This text: needs some description.
  The description can span multiple lines and paragraphs. All lines that
  belong to the description must be indented by two spaces.

Descriptions, Items and Enumerations can be mixed and nested as you like.


Accentuations
=============

GOSH supports accentuations for marking *bold* and _italic_ text. It uses
not the slash ('/') character to mark italic text because slashes are used
in pathnames, which are very likely to appear in GOSH texts. Additionally,
underlined text is rarely used. If you want to _mark multiple words_ you do
not need to (_but_you_can_) place '_' in-between the words.
All words 'that are written in apostrophes' will be considered as monospaced
text. This is useful for 'filenames' and the like. The beginning and the
end of the accentuated text fragment must be on the same line.

_If you need to span accentuations over multiple lines, you need to apply_
_the accentuation at each line. This, way the accentuation is also visible_
_in the GOSH text._

GOSH detects hexadecimal numbers by a leading '0x' and prints them in a
monospaced font automatically.


Text structure
##############

Head of a GOSH text
===================

The document title is the first text in the document. It is meant to be written
centered in the GOSH text. There must be at least one space at the beginning of
a title line. Otherwise, GOSH will consider the line as the first paragraph of
the document. The title can span multiple lines.

The title is followed by one or more empty lines and the author's names.  As
for the title, the author's names should be written in a centered way as well.

Example of a header of a GOSH text:

!         This is the title
!           of a gosh the
!             document
!
!          Bernd Ullrich
!          Uli Berndrich


You do not need to specify the author but it is recommended. You can also
specify neither the title nor the author. In this case the document is
just untitled.


Sections
========

The chapter's names are underlined with the '#' character:

! This is the name of a chapter
! #############################

Sections are underlined by '=' characters:

! Section
! =======

Subsections are underlined by '~' characters:

! Subsection
! ~~~~~~~~~~

Paragraphs are underlined by '-' characters:

! Paragraph
! ---------

I choose these underline characters based on their different heights.
A '#' is higher than '=' that is higher than '~' that is higher than
'-'. This way, the different levels of document structure can be easily
differentiated from each other.


Images
======

Images can be inserted into the document this way:

! [image filename] This is the caption of the image.
!   The caption can span multiple lines. Each line
!   must be indented by two spaces.

You can control the width of the image in relation to the page width via:

! [image filename 50%] This image will appear with the
!   size of a half page-width. This works only with the
!   LaTeX-backend of GOSH.

The image can be rotated via:

! [image filename 5°]

Of course, you can specify both parameters for the same image, too.


Tikz images
===========

Tikz images in the form of individual files can be incorporated into the
document. A tikz file contains one 'tikzpicture'. It can be inserted as
follows:

![tikz filename]
!  The optional caption describes the tikz image.

Note that there should be an empty line above and below the statement.
Otherwise, the statement will be interpreted as a reference that appears within
the surrounding paragraph. The filename must be specified without the '.tikz'
file extension. When no caption is provided, the image will be inserted at the
current text position. In contrast, when providing a caption, the image will
appear as a (potentially floating) figure that can be referenced via the
filename.


Tables
======

The table feature of GOSH is very preliminary, but it is still usable for a
lot of cases. Tables are drawn by '-' and '|' characters. Each line of a
table must be led by at least one space. The caption of a table can be
written similar to the caption of an image.

  directory | filename  | size
 --------------------------------
  /etc      | crontab   | 651
            | csh.login | 65
            | exports   | 114
 --------------------------------
  /sbin     | route     | 46680
            | portmap   | 12016

[table example_table] This is the caption of the table.

:Note: Two sequent tables without any text in-between cause problems with the
  current version of GOSH.


References
==========

Chapters, sections and subsections can be referenced within the document by
enclosing the corresponding name with brackets. For example, read section
[Licence] carefully. This makes it very easy to insert references but has the
drawback, that all referenced section names need to be different to avoid
ambiguous references.

Images can be referenced by their filenames (without the extension).  I use to
store all images of the document in a separate 'img/' folder.  This avoids
naming conflicts of image filenames and section names.  Tables can be
referenced by their identifiers.

If there is no matching identifier within the document, GOSH assumes the text
within the brackets is an external reference (citation). So you can insert
citations just the same way as references. This is very practical if you use
LaTeX and Bibtex.

GOSH detects HTML-links by a heading 'http://'. For example, take a look at
Atari.org [http://www.atari.org]. The HTML-backend supports the link text and a
title to be optionally specified. The link text is delimited from the _URL_ by
a '-', enclosed with spaces:

! [http://www.atari.org - The Atari Headquarter]

A title can be optionally specified with parenthesis:

! [http://www.dhs.nu - Dead Hackers Society (click here)]


The LaTeX backend
#################

The integrated LaTeX backend of GOSH can be tweaked via the following command
line arguments:

:'--tex-table-floating': This argument makes GOSH to create floating tables.
  By default, tables are inserted at the position of their definition.

When prefixing the name of a chapter or a section with an asterisk '*', then
this is translated into the latex syntax

!\section*{<name>}

That way you can define chapters and sections that are not listed in the
contents listing and they receive no index number.

By default, GOSH uses plain 'image' and 'table' environments. If you
prefer to use a 'image*' or 'table*' environment, you can add the attribute
'full-span' to the image or table tag. For example:

![image img/example 85% 5° full-span]


The HTML backend
################

By default, the HTML produces pure HTML code without any fancyness.
For the different textual styles, the corresponding HTML tags are used.

There exist the following command line options, which take effect on the HTML
output:

:'--html-toc': This option lets GOSH create a table of contents. The entries
  of the table link to their corresponding section.

:'--html-sec-enum': By default, chapters and sections are not enumerized.
  By using this option, you can make GOSH to prepend section numbers to the
  headlines.

:'--html-p-colored': This option allows any section type to be colored by a
  different color. The colors are defined inside the backend and can be
  over-defined via an additional style as described in section
  [Tweaking the GOSH output].

:'--html-p-justify': This option sets the alignment of paragraphs to justified.

:'--html-keep-tags': This option prevents GOSH from replacing '<' and '>'
  characters by the corresponding HTML sequences and thus, lets you embed
  HTML tags directly in your GOSH document.


Advanced features
#################

Tweaking the GOSH output
========================

The output of GOSH can easily be tweaked by supplying multiple '--style'
arguments. The style-files will be processed in the specified order.
For example if you want to tweak the HTML ouput to not contain a
header and tail, you can tweak the 'html.gosh' style by another
'rawcontent.gosh' style:

! > gosh --style html.gosh --sytle rawcontent.gosh gosh.txt > gosh.html

The 'rawcontent.gosh' file contains only the empty versions of the
functions for outputting the head and tail:

! proc produce_head_html {} {
! }
!
! proc produce_tail_html {} {
! }

The 'slides.gosh' backend is another example of this technique. It slightly
modifies the LaTeX output of GOSH to create Foiltex output. This way, you
can use GOSH to create 'slides' very easily.


File encodings
==============

By default, GOSH tries to detect the character encoding by examining the input
text via the 'file' command. As this Unix command is not always available, it
is possible to skip the detection mechanism and explicitely select the use of
UTF-8 encoding via the '--utf8' command-line argument.


Raw text
========

There are things like formulars, which are not supported by GOSH but by
the target format (such as LaTeX). You can insert source code fragments of
your target format directly into your GOSH text file by marking such lines
by a colon, followed by a space at the beginning of line:

! : This text will not be touched by
! : GOSH. It will be directly written
! : out in its original form.

When using this method, you loose the feature of GOSH to create different
target formats of your document because the raw content will certainly
conflict with the syntax of other formats (such as HTML).

For example the LaTeX sequence "': $e=mc^2$'" produces:

: $e=mc^2$


Annotations
===========

When writing papers, one often wants to make annotations to preliminary
revisions that should be printed in a sligtly accentuated way - so that
it is easy to differentiate annotations from real text. As GOSH comments
are completely ignored by GOSH, you will not be able to make printable
annotations via GOSH comments. Instead, you can use a pipe symbol, followed
by a space to mark annotated lines. Within such annotations, you can use
items, enumerations, descriptions and accentuations. This makes it easy
to convert annotations to real text by just clearing the leading pipe
symbol and space.

! | This is an *annotation* and will
! | be written in italic style.


Troubleshooting
###############

In this section you will find some hints for the use of GOSH. It will
grow as soon as people will report problems to me.

"Error: cannot figure out what you mean with"
---------------------------------------------

When GOSH is unable to parse its input file correctly, it outputs an error
message "Error: cannot figure out what you mean with", followed by the
trouble-making text. You should revisit this text passage. Mostly, this
message is caused by wrong indentation. You should make sure that you
indented items, enumerations, descriptions and captions with two spaces
and no TABS. Do not use TABS. GOSH does not recognize TABS.


Known bugs and limitations
##########################

* All references must be written completely on one line, including the
  brackets.


Contact
#######

If you have comments, tips or bug reports regarding GOSH, please do not
hesitate to contact me via

:Email:
  norman.feske@genode-labs.com