toplevel.pl

Print the Prolog banner message and messages registered using version/1.

version(+Message) is det

Add message to version/0

initialization :Goal

Runs Goal after loading the file in which this directive appears as well as after restoring a saved state.

See also: - initialization/2

Run goals registered with :- initialization(Goal, program).. Stop with an exception if a goal fails or raises an exception.

thread_initialization :Goal

Run Goal now and everytime a new thread is created.

$thread_init

Called by start_thread() from pl-thread.c before the thread's goal.

$initialise is semidet

Called from PL_initialise() to do the Prolog part of the initialization. If an exception occurs, this is printed and '$initialise' fails.

theme_changed(+Theme) is det

Called from C if the Prolog flag theme is about to get the new value Theme. Calls all solutions of theme_hook/1. Our own hook loads library(theme/Theme), unless Theme is already defined, i.e., theme/1 is true for it. This allows for a theme that is defined in memory, e.g., by a theme editor.

$toplevel

Called from PL_toplevel()

$compile

Toplevel called when invoked with -c option.

$config

Toplevel when invoked with --dump-runtime-variables

prolog:repl_loop_hook(+BeginEnd, +BreakLevel) is nondet[multifile]

Multifile hook that allows acting on starting/stopping the interactive REPL loop. Called as

forall(prolog:repl_loop_hook(BeginEnd, BreakLevel), true)

Arguments:

`BeginEnd`	- is one of `begin` or `end`
`BreakLevel`	- is 0 for the normal toplevel, -1 when non-interactive and >0 for break environments.

prolog

Run the Prolog toplevel. This is now the same as break/0, which pretends to be in a break-level if there is a parent environment.

$query_loop

Run the normal Prolog query loop. Note that the query is not protected by catch/3. Dealing with unhandled exceptions is done by the C-function query_loop(). This ensures that unhandled exceptions are really unhandled (in Prolog).

$answer_class(-Class) is semidet

Colour class for the answer that is being written, or fail if it must not be decorated. Class is answer(odd) or answer(even), alternating over the answers of a single query. Using a different background colour for both stripes the answers, which separates the answers of a non-deterministic query.

Only an answer that shows bindings, residual goals or delays is decorated: true. and false. are not answers to stripe.

Exported (and thus $-prefixed) because it is used by boot/messages.pl. It is not intended for use by applications.

$execute_query(Goal, Bindings, -Truth) is det

Execute Goal using Bindings.

residual_goals(:NonTerminal)

Directive that registers NonTerminal as a collector for residual goals.

prolog:residual_goals// is det

DCG that collects residual goals that are not associated with the answer through attributed variables.

prolog:translate_bindings(+Bindings0, -Bindings, +ResidueVars, +ResidualGoals, -Residuals) is det

Translate the raw variable bindings resulting from successfully completing a query into a binding list and list of residual goals suitable for human consumption.

Arguments:

Bindings - is a list of binding(Vars,Value,Substitutions), where Vars is a list of variable names. E.g. binding(['A','B'],42,[])` means that both the variable A and B have the value 42. Values may contain terms '$VAR'(Name) to indicate sharing with a given variable. Value is always an acyclic term. If cycles appear in the answer, Substitutions contains a list of substitutions that restore the original term.

Residuals - is a pair of two lists representing residual goals. The first element of the pair are residuals related to the query variables and the second are related that are disconnected from the query.