A quick start using Terzo.
--------------------------

This is a short tutorial describing how to start the Terzo
lambda-prolog interpreter, enter a module, and how to execute a query.

	On Unix systems, the directory which contains the Terzo
executable should be in your path, if it is, typing

% Terzo

(or whatever the executable is named - ask your system administrator)
and a carriage return should invoke the interpreter. Once the
iterpreter has started, you should be greeted with the "Terzo> "
prompt. You are now at the "loader" level of the interpreter, which
means that commands entered will be interpreted and executed by the
loader (see ???) until a command is entered which invokes one of the
other two levels of the interpreter.  The other levels are the module
entry loop and the interactive query interpreter.

	The module entry loop is started with a "#begin." statement.
Unless an error occurs, all following statements are read as module
declaration statements, until a matching "#end." statement is read of
end of file is reached. For instance:

Terzo> #begin.
module list_append.
list_append|	type append  list A -> list A -> list A -> o.
list_append|	
list_append|	append nil K K.
list_append|	append (X::XS) YS (X::ZS) :- append XS YS ZS.
list_append|	#end.
module list_append.
    type append  list A -> list A -> list A -> o.
Terzo> 

The interpreter should now have the module list_append available to it. To
execute a single query q against the this module, from the loader
prompt ("Terzo> ") type "#query list_append q". For example:

Terzo> #query list_append append (1::2::nil) (1000::nil) X.

X = 1 :: 2 :: 1000 :: nil 

Terzo> 

To enter the interactive query interpreter, type "#query list_append." at
the loader prompt.  

Terzo> #query list_append.
?- append X Y Z.

X = nil
Y = Z
Z = Z ;

X = X1 :: nil
Y = Y
Z = X1 :: Y ;

X = X1 :: X2 :: nil
Y = Y
Z = X1 :: X2 :: Y 

?- #end.
Terzo> 

The "#end." command exits the interactive query interpreter, while the
"#quit." command exits the loader.

?- quit.
Terzo> #quit.
%