Frequently Asked Questions

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Libero
Version 2.32

Frequently Asked Questions

Why is the documentation in HTML format?

We originally wrote the documentation using Microsoft Word 5.0 for MS-DOS, a fine word-processor that satisfied our minimalist preferences for a long time. Our target was PostScript on paper. Since those old days, we have changed our minds a little about the best way of moving information from our brains to yours. We like the idea of keeping the help 'on-line' in the literal sense. Effectively, this means using HTML. Now, our approach is two-fold. Firstly, we use HTML as the basic language. It's excellent for the job. Secondly, we have structured the documentation to suit. This means that the Libero documentation is less of a traditional paper book, and more of a hyper-linked text database. Our guiding principle is that you can take the entire HTML kit and put it on a local hard disk, then browse, print, and copy that. There are HTML browsers available for all of our target platforms, and the market is competitive and generally free.

Why do you not supply binary kits for UNIX (any longer)?

We used to do this... It just does not work very well, and takes a lot of work. It is generally not a good idea to use an executable built under one version of an operating system on an other. Sometimes, but not always, you can go from an earlier version of Brandix to a later version, but never contrarywise. With some exceptions (see next question) it's a snap to install Libero by compiling the source kit. At iMatix we tend to do this for all our products today.

I get compile errors on Sun Sparc

For some bizarre reason, possibly related to the struggle of commercialism over utility, this system does not come with an ANSI C compiler as standard. People often install GNU C, which works well, but there can be conflicts between the Sun header files and GNU runtime library. In theory we fixed these in version 2.11 (by changing prelude.h). If you still get compile errors, send us a listing and we will see what is wrong. On some Sparc systems, the ANSI C compiler is called acc.

I get compile and link errors and then lr dies

If you get compile errors (not warnings), or link errors, don't try to run the resulting executable. Or if you do, don't expect reasonable behaviour, unless one can describe a dump as 'reasonable'.

Does Libero support language X?

If it is not on the list, the answer is 'not yet'. There are several possible reasons why we have not yet built a schema for a particular languages:

We hate the language and would not touch it with a 10 ft pole.
We don't have a compiler or interpreter for that language;
We don't consider the language to be worth it;
We don't see a good way to implement dialogs in the language;
We have not had time yet.

So far no language has fallen into the first category, while many have fallen into the last.

How do I add support for language X?

If it is a language that we can easily get hold of, we'll add support more or less on demand. For instance, if anyone actually comes and asks for an Ada implementation, we could install GNU Ada and get an Ada schema up and running in a few days. The bizarre thing is we don't even ask for money for the whole business. Whatever.

If the language is one that we cannot get freely -- and we're not in the habit of buying expensive compilers just for fun -- then we can try to build a schema 'by remote control'. In this scenario, you provide us with the specifications of the language, sample programs, etc. We'll do the schema and send you programs to test. Eventually we get a solid version. This can work surprisingly well.

Finally, you can bite the bullet (more like a 10mm shell) and learn how Libero's schema language works. You can then write the schema yourself. Honestly, if you need to write a schema from scratch, this is probably the hard way.

I want to customise a schema

Firstly, be sure that you can't get what you need by adding code to the template file. Then, drop us a line to tell us what you want so we can try to figure-out a way of supporting it in the standard schemas. As a last resort, copy the schema and change it. If your changes are cosmetic, we'd try to convince you to accept our cosmetics. Some projects have such unusual needs that a new schema is the only practical answer. Be warned, however: if you make your own version of a schema, you lose the benefits of any future improvements or fixes to the schema.

I don't understand Libero

This is quite normal. Anyone who understands Libero the first time is either lying, has a serious mental problem, or is not a real programmer. The concept is simple, and easy to explain to a lay-person. But if you have spent long enough coercing computers to do your bidding, you get a certain world-view of how things work. Libero does things differently. Keep trying, and after a week or so you will suddenly see it.

How do I print-out the documentation?

Probably the best approach is to download the big file that contains the entire documentation kit. Load this into your favourite browser and press 'Print'. Alternatively you can try to convert the HTML file into a word processor format, load it up and print it like that. This is a field that is changing rapidly, for the better.

Why is there no UNIX Makefile?

There are several reasons for this: Libero is a portable product, and makefiles are specific to UNIX; we don't really like makefiles; we prefer to try a more 'intelligent' approach when possible; we don't have the time to make and maintain makefiles for all the possible UNIX platforms. Ok, none of these reasons is enough by itself, but you get the idea. Libero is simple to build and install, so the lack of a makefile is not a serious handicap.

Libero for Windows crashes

There was a bug in previous releases of Libero for Windows. It was caused by a missing Windows font. Install the latest version.

Why can't I get the files by ftp?

Our site does not provide anonymous ftp for reasons of speed and of security. If you do not have http access, send us an e-mail telling us what system you work with, or which files you want, and we'll send them by e-mail back to you.

Is there a mirror site?

Not to our knowledge, though we have seen a few older versions of Libero floating around.

How do I build a mirror site?

Our website does not (currently) support anonymous ftp, nor other protocols for automatic mirror-site replication. If you want to set-up a mirror site for Libero, contact us and we'll work-out the principles.

I want to repackage Libero for a CD-ROM

You do not need our permission, but you must respect our license terms. If your CD-ROM is for a specific platform, e.g. Linux, we suggest that you include the binary kit for that platform, the source kit, and the HTML kit. If you have space on the CD-ROM, supply the HTML tree uncompressed: then people can follow the links through their Internet connection to pick-up other files such as examples.

If your CD-ROM is a source collection, you may want to provide the Windows version of Libero, the source kit, and the HTML kit.

Why is Liberetto so silly?

Everything is relative. When the first issue of Libermanga comes out, you'll see what we mean. Seriously, though, we try to maintain a harmonious balance between education, entertainment, humour, and subtle irony. When that fails, we just go for silly.

Is there a 'pretty printer' for my dialogs?

Yes, since version 2.20 - use the -pretty option.

How is a Libero FSM different from a 'classic' FSM?

Libero lets you specify several actions in a transition; a classic FSM usually only lets you specify one action.
Some FSMs allow an 'entry action', a 'transition action', and an 'exit action'. These are all equivalent, as far as we can see, and since Libero allows multiple actions, you can do the same in Libero.
You describe your FSM as a textual diagram, not as a numbered graph, as is usually the case.
Libero stores the FSM in a table and interprets this. This is one of several approaches; some classic FSMs use goto's; others use a large switch statement. The table + interpreter approach is a reasonable compromise between space and speed and simplicity.
Libero has the concept of an exception event.
Libero has the concepts of super-states and default states.

I want my FSM to handle an event queue in realtime

Use our SMT kernel; this is our solution for event-handling in realtime programs, multi-FSM constructions, communications servers, internet servers, etc.

Are Libero FSMs good for writing parsers?

Well, in principle yes, but in practice there are better tools. For instance, Perl is great for writing ad-hoc parsers. If you are working with formal grammars, there are tools that will generate parsers for such grammars. It is usually pointless to re-invent the wheel by hand. There are exceptions. For instance, sometimes the grammar cannot be formalised enough to work with a parser generator. Sometimes a generated parser is too slow. In these cases, a Libero FSM may produce excellent results.

I downloaded a Libero .zip file to my UNIX, then ftp'd it to my PC - now PKUNZIP won't extract it

When you ftp a binary file like a .zip file, always set ftp to binary mode (use the command 'bin'). Sometimes ftp is configured like this by default, but more often it assumes you want to transfer text files. So, it expands tabs, converts line-ending, and such, generally turning a .zip file into garbage along the way.

Is there a Libero mailing list?

No, not yet. Each month we send out Liberetto, our fanzine. We include the most interesting mail we get, news about changes to Libero, forthcoming releases, etc. This is the closest thing to a discussion group so far. We intend one day to create a usenet news group. A public mailing list may be one step on the way. We welcome any suggestions.

Libero for Windows complains 'ASSOC.VBX Not Found'

To use Libero for Windows you need to download TWO .zip files; lrmswin.zip and lrmswins.zip. The second contains 'system files' including various .vbx files. To download an update you only take the first .zip file. This saves download time.