Term::TUI - simple tool for building text-based user interfaces


If TUI_Run is the only routine being used:

  use Term::TUI;


If other TUI subroutines are used:

  use Term::TUI qw(:all);




Many times, I've wanted to quickly write a nice text-based user interface around a set of perl routines only to end up writing the full (though simple) parser and interface to make it nice enough, and friendly enough, to be usable.

This module creates a simple but powerful text based user interface around perl routines, adding such features as command line history, command line editing, online help, and command completion, while hiding all details of the interface from the programmer.

The interface is described in a simple hash which is passed to the TUI_Run command. This routine exits only when the user has exited the program (returning a flag signalling any special exit conditions).


  use Term::TUI;

The TUI_Run command is used to run the interface. It prompts the user for commands and executes them (based on description of passed in as %desc) until the user exits. The return flag is 0 unless the user exited with the Abort command when it is 1.

  use Term::TUI qw(:all);
  $flag=TUI_Script(\%desc,$script [,$sep]);

This allows you to pass in commands in a "script" instead of an interactive session. The script is a series of commands separated by a semicolon (or the string included in $sep).

  use Term::TUI qw(:all);

Returns the version of the module.

  use Term::TUI qw(:all);

This is used in the routines given in the description hash to send a message to STDOUT.


The interface allows you to describe multiple "modes" organized in a simple tree-like hierarchy (or modes, submodes, subsubmodes, etc.), each of which has it's own set of commands specific to that mode. I've modeled it after a unix filesystem with directories being "modes" and executables being equivalent to commands. So, you might want to model the following tree:

      math                 string
      |                    |
      +-----+-----+        +------+
      hex   add*  mult*    len*   subs*
      add*  mult*

Here the "executables" are marked with asterixes(*). So in math mode, you could type "add" or "mult" to add a list of numbers together or multiply them together. It also has a submode "hex" where you can do that in hexidecimal.

I find this type of interface very conveniant in many cases, but a nuisance to write. This module handles this trivially. The above interface can be written with the following 2 perl commands:

   %modes =
    (".HELP"  => "This is the main help.\nNot a lot of info here.",
     "math"   => {".HELP" => "A simple calculator.  Currently it can\n" .
                             "only add and multiply in hex or decimal.",
                  "add"   => [ "Add numbers together."  ,    Add,0 ],
                  "mult"  => [ "Multiply numbers together.", Mult,0 ],
                  "hex"   => {".HELP"  => "Math in hex.",
                              "add"   => [ "Add hex numbers together.",
                                           Add,1 ],
                              "mult"  => [ "Multiply hex numbers together.",
                                           Mult,1 ]
     "string" => {".HELP" => "String operations",
                  "subs"  => [ "Take STRING,POS,LEN and returns substring.",
                               Substring ],
                  "len"   => [ "Returns the length of a string.",
                               Length ]

   print "*** ABORT ***\n"  if ($flag);

You also have to write an Add, Mult, Substring, and Length subroutine of course, but once that's done, you end up with a rather nice text based user interface. The following are excerpts from a session using the sample interface defined above:

Changing modes is trivial. Just type in the new mode using a syntax similar to the unix filesystem:

   sample> string
   sample:string> /math/hex
   sample:math/hex> ..
   sample:math> hex
   sample:math/hex> /

When in a given mode, you can just type commands relevant to that mode:

   sample:string> subs barnyard 1 3
     Substring = arn
   sample:string> len barnyard
     Length = 8

You can also explicitely type in the mode for a command. In this situation, commands can be typed as MODE/CMD ARGS or MODE CMD ARGS equivalently:

   sample:string> /math/hex/add 4 6 1
     Total = b
   sample:string> /math mult 4 6 2
     Total = 48

There are several built-in commands including "..", "/", "help", "abort", "exit", and "quit". The last two ("exit" and "quit") are equivalent and mean to exit and return 0. "abort" exits with a value of 1.

There is also online help:

   sample> help

   This is the main help.
   Not a lot of info here.

   Additional help:

      Modes: math string
      Cmds : .. / abort exit help quit

   sample> help /string

   String operations

   Additional help:

      Cmds : .. / abort exit help quit
             len subs

   sample> math
   sample:math> help

   A simple calculator.  Currently it can only
   add and multiply in hex or decimal.

   Additional help:

      Modes: hex
      Cmds : .. / abort exit help quit
             add mult

   sample:math> help add

   Add numbers together.

   sample:math> help /string len

   Returns the length of a string.

   sample:math> help /string/subs

   Take STRING,POS,LEN and returns a substring.

Currently, Term::TUI does not have much in the way of bells and whistles, and I doubt it ever will. It's not designed for a full-blown, feature-rich user interface. It's mainly intended for simple control or config tools (similar to lpc for example) used primarily by the sysadmin type people (who else is interested in a text-based interface after all :-).

There is also a non-interactive form which allows the same interface to be called in scripts.

   TUI_Script(\%modes,"/math add 3 5; string; subs barnyard 1 3");


   Total = 8
   Substring = arn

TUI DOES use one of the Term::ReadLine modules for the interactive session, so if you have Term::ReadLine::GNU or Term::ReadLine::Perl installed, you can use things like command history and command line editing.


When ending a Term::TUI program, you may get:

   Warning: unable to close filehandle properly:
            Bad file descriptor during global destruction.

This is due to a bug in either the Term::ReadLine or Term::ReadLine::Gnu module. Using a recent version of Term::ReadLine::Gnu will get rid of this.


This script is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


Sullivan Beck (