There are several methods available today to prepare Indian language documents with computers. Many of these come under the group of wordprocessors and desktop publishing software. lb was not designed to work with files generated from any of these software.( Microsoft word, Pagemaker etc). At IIT Madras, a unique and simple Editor program has been developed to permit very easy entry of Indian language texts using the ordinary computer keyboard. The interesting feature of this program is that it can be used on many computers in the world today. More importantly, the IIT Madras system allows the documents prepared using this editor to be freely moved from one computer to another thus avoiding the use of special conversion programs.
We shall first give a brief description of "lb". lb stands for "local language browser". When used on a computer, the document to be displayed by "lb" is indicated by giving the name of the file(document) to "lb".
The way "lb" is invoked on a computer will depend on the specific features provided by the system software on that computer. Computers which operate under DOS or Unix usually present what is known as the Command Line Inteface. Systems such as the MacIntosh have a different user interface where the program is invoked by clicking the mouse cursor on the program icon or the icon of the document to be viewed by the program.
On DOS, UNIX, XWINDOWS systems presenting a command line interface a user would type
lb viewfile.llf [lang]
Here viewfile.llf is the file the user wishes to see in the language specified by the option lang. lang can be one of about a dozen different Indian languages. The phonetic nature of Indian language permits text prepared in one language to be displayed in any other language. In the sample documents provided one would see files such as gita.llf, kural.llf, sample.llf etc. "llf" is the suggested convention for naming Indian language files on the computer.
The MacIntosh does not present a commandline interface. Instead it uses Icons to represent files and documents. The icon for "lb" is the familiar "Om" symbol. No specific icon has been assigned to Indian language files as such but one can identify them from the llf extensions.
When lb starts it may display a banner depending on the default options set and will ask the user to press the space bar on the key board. The text in the appropriate language will then appear in a window. Given below is an inline graphics image of such an opening screen for the gita.llf file.
The user can scroll through the text by using the arrow keys or specific letters on the keyboard. Equivalently if a mouse is connected the mouse scroll bar may be used. Adequate on-line help is available by pressing the h key. The browser also displays the total number of lines in the text and the number of the last displayed line in the window.
The window may be resized using the procedure adopted on each system. When a window is resized, the window will refresh itself. On systems running DOS the resizing option is not supported. ( Note: Please do not resize or switch windows when the browser is accepting some keyboard input or when it displays the banner. This may cause unpredictable results depending on the system on which lb is run).
The browser allows a transliteration feature using which Roman transliteration of the first line of displayed text is seen in a small window at the bottom of the display window.
Under DOS and X WINDOWS, three small icons displaying the symbols " T ,? ,X" are included to invoke transliteration , help or exit from the browser respectively.
Note: Roman transliteration is set for Indian languages only. Consequently transliterating other language texts would produce incorrect transliteration. Hebrew text can however be properly transliterated using a language " ipaheb " in place of " ipa ". Please read the section on the names assigned to different languages to see how "ipaheb" can be used.
Here is a Unix-style user manual for "lb"
If lb is able to identify the presence of these characters, it will display the document. A question mark will be seen whenever lb cannot relate a character in the text to the set supported for the language. Since arbitrary files will have no self identifying information, the base language used by lb is selected from the configuration file. If there is some problem using this language (the support files might not be present) then "lb" will try and use "ipa" which is included with the distribution of "lb". If this fails, "lb" will exit with an error message.
The IIT M software uses the concept of an environment variable for this purpose. The idea is simple. The environment variable tells where the files are. This variable is designated as LANGDIR and must be specified before invoking lb. The actual manner in which an environment variable is specified depends on the system on which "lb" is run. For the sake of uniformity, it is recommended that in all systems, the user create a subdirectory called "llang" at some convenient place and put all the support file in a subdirectory "files" under " llang ". The Macintosh is a little different in that it is difficult to specify an environment variable. It is recommended that the user create a folder called "files" within the folder "llang" and move all the support files to it.
set LANGDIR= base\llang\files where base is the path leading to llang. The same applies for WINDOWS 3.1 and WINDOWS 95. Please make sure this is done before starting Windows.
setenv LANGDIR $HOME/llang/files
LANGDIR=$HOME/llang/files
export LANGDIR If LANGDIR is not specified, lb will look for all the support files in the current directory from which it was invoked.