FAQs - Frequently Asked Questions

If you have a doubt about Abaco the current section may be useful.  If this and all the other sections of this help don't work, you can send your question to abaco-1@cin.ufpe.br.


1 - The standard sort union symbol ('|') doesn't  work, so how can I represent sort union?

R - In the current Abaco version the union of sorts is not directly implemented, due to concerns about eficiency.  Perhaps in the future this can be done.  But if you wish to interpret something like "give the given (integer | truth-value)", you can write instead:   

                                    eq integer <= value .
                                    eq truth-value <= value .

                                    ... give the given value ...

2 - The expression "run (var a 1)" is not correctly interpreted, but  "run (var x 1)" is.  Why does it happen?

R -In the current version Abaco's primary parser doesn't recognise terms belonging to two lexical classes (i.e.: a variable with the same name as a reserved word).  In this special case, the word "a" is part of an operator "allocate a cell", so it can't be interpreted as an identyfier.            

3 - How can I write a dot ('.') in the middle of an expression such as a.b.c?

R - In the current version reserved words can be added if you put them in brackets (a.b).