- break
-
Recursively start a new Prolog top level. This Prolog top level has its
own stacks, but shares the heap with all break environments and the top
level. Debugging is switched off on entering a break and restored on
leaving one. The break environment is terminated by typing the system's
end-of-file character (control-D). If the
-t toplevel command line option is given
this goal is started instead of entering the default interactive top
level (prolog/0).
- abort
-
Abort the Prolog execution and start a new top level. If the
-t toplevel command line options is given
this goal is started instead of entering the default interactive top
level. Break environments are aborted as well. All open files except for
the terminal related files are closed. The input- and output stream
again refers to user. (17)
- halt
-
Terminate Prolog execution. Open files are closed and if the command
line option -tty is not active the terminal status (see
Unix stty(1)) is restored. Hooks may be registered both in Prolog and in
foreign code. Prolog hooks are registered using at_halt/1. halt/0
is equivalent to
halt(0).
- halt(+Status)
-
Terminate Prolog execution with given status. Status is an integer. See
also halt/0.
- prolog
-
This goal starts the default interactive top level. Queries are read
from the stream
user_input. See also the history
feature (feature/2).
The prolog/0
predicate is terminated (succeeds) by typing the end-of-file character
(Unix: control-D).
The following two hooks allow for expanding queries and handling the
result of a query. These hooks are used by the toplevel variable
expansion mechanism described in section 2.8.
- expand_query(+Query,
-Expanded, +Bindings, -ExpandedBindings)
-
Hook in module
user, normally not defined. Query
and
Bindings represents the query read from the user and the
names of the free variables as obtained using read_term/3.
If this predicate succeeds, it should bind Expanded and ExpandedBindings
to the query and bindings to be executed by the toplevel. This predicate
is used by the toplevel (prolog/0).
See also expand_answer/2
and
term_expansion/2.
- expand_answer(+Bindings,
-ExpandedBindings)
-
Hook in module
user, normally not defined. Expand the
result of a successfully executed toplevel query. Bindings is
the query
<Name>=<Value> binding list
from the query. ExpandedBindings must be unified with the
bindings the toplevel should print.