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8 CHAPTER 1. The TOY(FD) System

To load the new deﬁnition choose ‘y’; however, if we have redeﬁned a set of func-

tions is useful to choose the option ‘p’ to avoid the repetitive process of showing

multiple messages as that presented above and load all the new deﬁnitions.

• /run(< file >) combines both commands showed above and executes in se-

quence the two operations /compile(< file >) + /load(< file >).

It is not possible, in the current version, to compile simultaneously several programs

(observe that compile, load y run admits only one argument), but the same eﬀect can

be reached with the directive include explained further in Section 2.1.

During the compilation of a program, TOY(FD) works as TOY and processes the

entry (i.e., the ﬁle) in several stages: initially it checks for the syntax, functional

dependencies and types; then, if there is no error, it generates the Prolog code and

during this process it visualizes useful information to the user.

Once a program is compiled, the user can write goals at the TOY(FD) command

line in a similar form as for Prolog programs. See for instance Section 1.3.5.

1.3.3 Information about Functions

There are also two commands that allow to get information about functions that has

been deﬁned in a program:

• /type(< fun >) shows the type of the function < f un >, if this is deﬁned in

the program loaded (currently in memory) in the TOY(FD) session.

• /tree(< f ile >,< fun >) provides information about the translation that

TOY(FD) has generated for the function < fun > deﬁned in the ﬁle < file >.

Particularly, it shows the deﬁnitional tree associated to the function L´opez-

Fraguas and S´anchez-Hern´andez, 1999.

1.3.4 Saving the session

Another useful command is /save(< file >) that allows to keep the current state of

a session (with the whole set of predicate deﬁnitions, functions, types, etc.) to the ﬁle

< f ile >.

To restore the state, we only have to execute the ﬁle < f ile > from a command

interpreter level (this have been tested in UNIX).

1.3.5 Activating the Output for FD Constraint Solving

TOY(FD) does not incorporate automatically FD constraints and thus it is necessary

to load the extension for FDs and activate the output in order to visualize the results

of constraint solving.

To show the current state of the constraint store with resp ect to the variables in the

goal, is is necessary to activate the constraint output. This is done with the following

command:

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Ascend FD-23R Manual de usuario Pagina 20