Summary of Built-In Predicates

! [ISO]

Commits to any choices taken in the current predicate.

(+P,+Q) [ISO]

P and Q.

(Head --> Body) [Reserved]

Not a built-in predicate; reserved syntax for grammar rules.

(+P -> +Q ; +R) [ISO]

If P then Q else R, using first solution of P only.

(+P -> +Q) [ISO]

If P then Q else false, using first solution of P only.

[]

[:File|+Files]

Updates the program with interpreted clauses from File and Files.

(:- Directive) [Reserved]

Not a built-in predicate; reserved syntax for directives.

(?- Query) [Reserved]

Not a built-in predicate; reserved syntax for queries.

(Head :- Body) [Reserved]

Not a built-in predicate; reserved syntax for clauses.

(+P;+Q) [ISO]

P or Q.

?X = ?Y [ISO]

The terms X and Y are unified.

+Term =.. ?List [ISO]

?Term =.. +List [ISO]

The functor and arguments of the term Term comprise the list List.

+X =:= +Y [ISO]

X is numerically equal to Y.

?Term1 == ?Term2 [ISO]

The terms Term1 and Term2 are strictly identical.

+X =\= +Y [ISO]

X is not numerically equal to Y.

+X =< +Y [ISO]

X is less than or equal to Y.

+X > +Y [ISO]

X is greater than Y.

+X >= +Y [ISO]

X is greater than or equal to Y.

?X \= ?Y [ISO]

X and Y are not unifiable.

?X ^ :P

Executes the procedure call P.

\+ +P [ISO]

Goal P is not provable.

?Term1 \== ?Term2 [ISO]

The terms Term1 and Term2 are not strictly identical.

+X < +Y [ISO]

X is less than Y.

?Term1 @=< ?Term2 [ISO]

The term Term1 precedes or is identical to the term Term2 in the standard order.

?Term1 @> ?Term2 [ISO]

The term Term1 follows the term Term2 in the standard order.

?Term1 @>= ?Term2 [ISO]

The term Term1 follows or is identical to the term Term2 in the standard order.

?Term1 @< ?Term2 [ISO]

The term Term1 precedes the term Term2 in the standard order.

?=(?X,?Y)

X and Y are either syntactically identical or syntactically non-unifiable.

abolish(:Preds) [ISO]

Makes the predicate(s) specified by Preds undefined.

abolish(:Atom,+Arity)

Makes the predicate specified by Atom/Arity undefined.

abort

Aborts execution of the current query (returns to C in recursive calls to Prolog from C).

absolute_file_name(+RelativeName,?AbsoluteName)

absolute_file_name(+RelativeName,?AbsoluteName,+Options)

AbsoluteName is the absolute pathname of RelativeName.

add_breakpoint(:Conditions, ?BID)

Creates a breakpoint with Conditions and with identifier BID. (Not available in runtime systems).

arg(+ArgNo,+Term,?Arg) [ISO]

The argument ArgNo of the term Term is Arg.

ask_query(+QueryClass, +Query, +Help, -Answer) [Hookable]

Prints the question Query, then reads and processes user input according to QueryClass, and returns the result of the processing, the abstract answer term Answer. The Help message is printed in case of invalid input.

assert(:Clause)

assert(:Clause,-Ref)

Asserts clause Clause with unique identifier Ref.

asserta(:Clause) [ISO]

asserta(:Clause,-Ref)

Asserts Clause as first clause with unique identifier Ref.

assertz(:Clause) [ISO]

assertz(:Clause,-Ref)

Asserts Clause as last clause with unique identifier Ref.

at_end_of_line

at_end_of_line(Stream)

The end of stream or end of line has been reached for Stream or from the current input stream.

at_end_of_stream [ISO]

at_end_of_stream(Stream) [ISO]

The end of stream has been reached for Stream or from the current input stream.

atom(?X) [ISO]

X is currently instantiated to an atom.

atom_chars(+Atom,?CharList) [ISO only]

atom_chars(?Atom,+CharList) [ISO only]

The name of the atom Atom is the list of one-char atoms CharList.

atom_chars(+Atom,?CodeList) [SICStus only]

atom_chars(?Atom,+CodeList) [SICStus only]

The name of the atom Atom is the list of character codes CodeList.

atom_codes(+Atom,?CodeList) [ISO]

atom_codes(?Atom,+CodeList) [ISO]

The name of the atom Atom is the list of character codes CodeList.

atom_concat(+Atom1,+Atom2,?Atom12) [ISO]

atom_concat(?Atom1,?Atom2,+Atom12) [ISO]

Atom Atom1 concatenated with Atom2 gives Atom12.

atom_length(+Atom,?Length) [ISO]

Length is the number of characters of the atom Atom.

atomic(?X) [ISO]

X is currently instantiated to an atom or a number.

bagof(?Template,:Goal,?Bag) [ISO]

Bag is the bag of instances of Template such that Goal is satisfied (not just provable).

block Specs [Declaration]

Not a built-in predicate; block declaration.

bb_delete(+Key,?Term)

Delete from the blackboard Term stored under Key.

bb_get(+Key,?Term)

Get from the blackboard Term stored under Key.

bb_put(+Key,+Term)

Store the term Term under Key on the blackboard.

bb_update(:Key, ?OldTerm, ?NewTerm)

Replace the term OldTerm by the term NewTerm under Key on the blackboard.

break

Invokes a recursive top-level. (Not available in runtime systems).

breakpoint_expansion(+Macro, -Body) [Hook]

user:breakpoint_expansion(+Macro, -Body)

Defines debugger condition macros.

byte_count(+Stream,?N)

N is the number of bytes read/written on stream Stream.

'C'(?S1,?Terminal,?S2)

Grammar rules. S1 is connected by the terminal Terminal to S2.

call(:Term) [ISO]

(Module::Term)

Executes the procedure call Term in Module.

call_cleanup(:Goal,:Cleanup)

Executes the procedure call Goal. When Goal succeeds deterministically, is cut, fails, or raises an exception, Cleanup is executed.

call_residue(:Goal,?Residue)

Executes the procedure call Goal. Any floundered goals and the variables they are blocked on occur as VarSet-Goal pairs in Residue.

callable(?X)

X is currently instantiated to a compound term or an atom.

character_count(+Stream,?Count)

Count characters have been read from or written to the stream Stream.

catch(:ProtectedGoal,?Pattern,:Handler) [ISO]

Executes the procedure call ProtectedGoal. If during the execution throw(Exception) or raise_exception(Exception) is called, and Exception matches Pattern, the execution of ProtectedGoal aborts, Pattern is unified with a copy of Exception and Handler is called.

char_code(+Char,?Code) [ISO]

char_code(?Char,+Code) [ISO]

Code is the character code of the one-char atom Char.

char_conversion(+InChar, +OutChar) [ISO]

The mapping of InChar to OutChar is added to the character-conversion mapping.

clause(:Head,?Body) [ISO]

clause(:Head,?Body,?Ref)

clause(?Head,?Body,+Ref)

There is an interpreted clause whose head is Head, whose body is Body, and whose unique identifier is Ref.

close(+Stream) [ISO]

close(+Stream, +Options) [ISO]

Closes stream Stream, with options Options.

compare(?Op,?Term1,?Term2)

Op is the result of comparing the terms Term1 and Term2.

compile(:Files)

Compiles in-core the clauses in text file(s) Files.

compound(?X) [ISO]

X is currently instantiated to a term of arity > 0.

consult(:Files)

Updates the program with interpreted clauses from file(s) Files.

copy_term(?Term,?CopyOfTerm) [ISO]

CopyOfTerm is an independent copy of Term.

create_mutable(+Datum,-Mutable)

Mutable is a new mutable term with current value Datum.

current_atom(?Atom)

One of the currently defined atoms is Atom.

current_breakpoint(:Conditions, ?BID, ?Status, ?Kind)

There is a breakpoint with conditions Conditions, identifier BID, enabledness Status, and kind Kind. (Not available in runtime systems).

current_char_conversion(?InChar, ?OutChar) [ISO]

InChar is mapped to OutChar in the current character-conversion mapping.

current_input(?Stream) [ISO]

Stream is the current input stream.

current_key(?KeyName,?KeyTerm) [Obsolescent]

There is a recorded item in the internal database whose key is KeyTerm, the name of which is KeyName.

current_module(?Module)

Module is a module currently in the system.

current_module(?Module,?File)

Module is a module currently in the system, loaded from File.

current_op(?Precedence,?Type,?Op) [ISO]

Atom Op is an operator type Type precedence Precedence.

current_output(?Stream) [ISO]

Stream is the current output stream.

current_predicate(?Name/?Arity) [ISO]

A user defined or library predicate is named Name, arity Arity.

current_predicate(?Name,:Head)

current_predicate(?Name,-Head)

A user defined or library predicate is named Name, most general goal Head.

current_prolog_flag(?FlagName,?Value) [ISO]

Value is the current value of the Prolog flag FlagName.

current_stream(?AbsFileName,?Mode,?Stream)

There is a stream Stream associated with the file AbsFileName and opened in mode Mode.

debug

Switches on debugging in leap mode (not available in runtime systems).

debugger_command_hook(+DCommand,?Actions) [Hook]

user:debugger_command_hook(+DCommand,?Actions)

Allows the interactive debugger to be extended with user-defined commands.

debugging

Displays debugging status information

dif(?X,?Y)

The terms X and Y are different.

disable_breakpoints(+BIDs)

Disables the breakpoints specified by BIDs. (Not available in runtime systems).

discontiguous Specs [Declaration,ISO]

Not a built-in predicate; discontiguous declaration.

display(?Term)

Displays the term Term on the standard output stream.

dynamic Specs [Declaration,ISO]

Not a built-in predicate; dynamic declaration.

enable_breakpoints(+BIDs)

Enables the breakpoints specified by BIDs. (Not available in runtime systems).

ensure_loaded(:Files) [ISO]

Compiles or loads the file(s) Files if need be.

erase(+Ref)

Erases the clause or record whose unique identifier is Ref.

error_exception(+Exception) [Hook]

user:error_exception(+Exception)

Exception is an exception that traps to the debugger if it is switched on.

execution_state(:Tests)

Tests are satisfied in the current state of the execution. (Not available in runtime systems).

execution_state(+FocusConditions, :Tests)

Tests are satisfied in the state of the execution pointed to by FocusConditions. (Not available in runtime systems).

expand_term(+Term1,?Term2)

The term Term1 is a shorthand which expands to the term Term2.

fail [ISO]

false

False.

fcompile(:Files) [Obsolescent]

Compiles file-to-file the clauses in text file(s) Files (not available in runtime systems).

file_search_path(Alias,?Expansion) [Hook]

user:file_search_path(Alias,?Expansion)

Tells how to expand Alias(File) file names.

fileerrors

Enables reporting of file errors.

findall(?Template,:Goal,?Bag) [ISO]

findall(?Template,:Goal,?Bag,?Remainder)

A prefix of Bag is the list of instances of Template such that Goal is provable. The rest of Bag is Remainder or the empty list.

float(?X) [ISO]

X is currently instantiated to a float.

flush_output [ISO]

flush_output(+Stream) [ISO]

Flushes the buffers associated with Stream.

foreign(+CFunctionName,+Predicate) [Hook]

foreign(+CFunctionName,+Language,+Predicate) [Hook]

Tell Prolog how to define Predicate to invoke CFunctionName.

foreign_file(+ObjectFile,+Functions) [Hook,obsolescent]

Tells Prolog that foreign functions Functions are in file ObjectFile. Use foreign_resource/2 instead.

foreign_resource(+ResourceName,+Functions) [Hook]

Tells Prolog that foreign functions Functions are in resource ResourceName.

format(+Format,:Arguments)

format(+Stream,+Format,:Arguments)

Writes Arguments according to Format on the stream Stream or on the current output stream.

freeze(?Var,:Goal)

Blocks Goal until nonvar(Var) holds.

frozen(-Var,?Goal)

The goal Goal is blocked on the variable Var.

functor(+Term,?Name,?Arity) [ISO]

functor(?Term,+Name,+Arity) [ISO]

The principal functor of the term Term has name Name and arity Arity.

garbage_collect

Performs a garbage collection of the global stack.

garbage_collect_atoms

Performs a garbage collection of the atoms.

gc

Enables garbage collection of the global stack.

generate_message_hook(+Message, -L0, -L) [Hook]

user:generate_message_hook(+Message, -L0, -L)

A way for the user to override the call to 'SU_messages':generate_message/3 in the message generation phase in print_message/2.

get(?C) [Obsolescent]

get(+Stream,?C) [Obsolescent]

The next printing character from the stream Stream or from the current input stream is C.

get0(?C) [Obsolescent]

get0(+Stream,?C) [Obsolescent]

The next character from the stream Stream or from the current input stream is C.

get_byte(?Byte) [ISO]

get_byte(+Stream,?Byte) [ISO]

Byte is the next byte read from the binary stream Stream.

get_char(?Char) [ISO]

get_char(+Stream,?Char) [ISO]

Char is the one-char atom naming the next character read from text stream Stream.

get_code(?Code) [ISO]

get_code(+Stream,?Code) [ISO]

Code is the character code of the next character read from text stream Stream.

get_mutable(?Datum,+Mutable)

The current value of the mutable term Mutable is Datum.

goal_expansion(+Goal,+Module,-NewGoal) [Hook]

user:goal_expansion(+Goal,+Module,-NewGoal)

Defines a transformation from Goal in module Module to NewGoal.

goal_source_info(+AGoal, ?Goal, ?SourceInfo)

Decomposes the annotated goal AGoal into a Goal proper and the SourceInfo descriptor term, indicating the source position of the goal.

ground(?X)

X is currently free of unbound variables.

halt [ISO]

Halts Prolog. (returns to C in recursive calls to Prolog from C).

halt(Code) [ISO]

Halts Prolog immediately, returning Code.

help [Hookable]

Prints a help message (not available in runtime systems).

if(+P,+Q,+R)

If P then Q else R, exploring all solutions of P.

include Specs [Declaration,ISO]

Not a built-in predicate; include declaration.

incore(+Term) [Obsolescent]

Executes the procedure call Term.

initialization :Goal [ISO]

Includes Goal to the set of goals which shall be executed after the file that is being loaded has been completely loaded.

instance(+Ref,?Term)

Term is a most general instance of the record or clause uniquely identified by Ref.

integer(?X) [ISO]

X is currently instantiated to an integer.

?Y is +X [ISO]

Y is the value of the arithmetic expression X.

is_mutable(?X)

X is currently instantiated to a mutable term.

keysort(+List1,?List2)

The list List1 sorted by key yields List2.

leash(+Mode)

Sets leashing mode to Mode (not available in runtime systems).

length(?List,?Length)

The length of list List is Length.

library_directory(?Directory) [Hook]

user:library_directory(?Directory)

Tells how to expand library(File) file names.

line_count(+Stream,?N)

N is the number of lines read/written on stream Stream.

line_position(+Stream,?N)

N is the number of characters read/written on the current line of Stream.

listing

listing(:Specs)

Lists the interpreted predicate(s) specified by Specs or all interpreted predicates in the type-in module. Any variables in the listed clauses are internally bound to ground terms before printing. Any attributes or blocked goals attached to such variables will be ignored. % If this causes any blocked goals to be executed, the behavior is undefined.

load(:Files) [Obsolescent]

Loads .ql file(s) Files.

load_files(:Files)

load_files(:Files, +Options)

Loads source, .po or .ql file(s) Files obeying Options.

load_foreign_files(:ObjectFiles,+Libraries) [Hookable,obsolescent]

Links object files ObjectFiles into Prolog. Use splfr and load_foreign_resource/1 instead.

load_foreign_resource(:Resource)

Loads foreign resource Resource into Prolog.

message_hook(+Severity, +Message, +Lines) [Hook]

user:message_hook(+Severity, +Message, +Lines)

Overrides the call to print_message_lines/3 in print_message/2. A way for the user to intercept the abstract message term Message of type Severity, whose translation is Lines, before it is actually printed.

meta_predicate Specs [Declaration]

Not a built-in predicate; meta-predicate declaration.

mode Specs [Declaration]

Not a built-in predicate; mode declaration.

module(+Module)

Sets the type-in module to Module.

module(+Module, +ExportList) [Declaration]

module(+Module, +ExportList, +Options) [Declaration]

Not a built-in predicate; module declaration.

multifile Specs [Declaration,ISO]

Not a built-in predicate; multifile declaration.

name(+Const,?CharList) [Obsolescent]

name(?Const,+CharList)

The name of atom or number Const is the string CharList. Subsumed by atom_chars/2 and number_chars/2.

nl [ISO]

nl(+Stream) [ISO]

Outputs a new line on stream Stream or on the current output stream.

nodebug

Switches off debugging (not available in runtime systems).

nofileerrors

Disables reporting of file errors.

nogc

Disables garbage collection of the global stack.

nonvar(?X) [ISO]

X is a non-variable.

nospy :Spec

Removes spypoints from the predicate(s) specified by Spec (not available in runtime systems).

nospyall

Removes all spypoints (not available in runtime systems).

notrace

nozip

Switches off debugging (not available in runtime systems).

number(?X) [ISO]

X is currently instantiated to a number.

number_chars(+Number,?CodeList) [SICStus only]

number_chars(?Number,+CodeList) [SICStus only]

The name of the number Number is the list of character codes CodeList.

number_chars(+Number,?CharList) [ISO only]

number_chars(?Number,+CharList) [ISO only]

The name of the number Number is the list of one-char atoms CharList.

number_codes(+Number,?CodeList) [ISO]

number_codes(?Number,+CodeList) [ISO]

The name of the number Number is the list of character codes CodeList.

numbervars(?Term,+N,?M)

Number the variables in the term Term from N to M-1.

once(+P) [ISO]

Finds the first solution, if any, of goal P.

on_exception(?Pattern,:ProtectedGoal,:Handler)

Executes the procedure call ProtectedGoal. If during the execution throw(Exception) or raise_exception(Exception) is called, and Exception matches Pattern, the execution of ProtectedGoal aborts, Pattern is unified with a copy of Exception and Handler is called.

op(+Precedence,+Type,+Name) [ISO]

Makes atom(s) Name an operator of type Type precedence Precedence.

open(+FileName,+Mode,-Stream) [ISO]

open(+FileName,+Mode,-Stream,+Options) [ISO]

Opens file FileName in mode Mode with options Options as stream Stream.

open_null_stream(-Stream)

Opens an output stream to the null device.

otherwise

True.

peek_byte(?N) [ISO]

peek_byte(+Stream,?N) [ISO]

N is the next byte peeked at from the binary stream Stream or from the current input stream.

peek_char(?N) [SICStus only]

peek_char(+Stream,?N) [SICStus only]

N is the character code of the next character peeked at from Stream or from the current input stream.

peek_char(?N) [ISO only]

peek_char(+Stream,?N) [ISO only]

N is the one-char atom of the next character peeked at from the text stream Stream or from the current input stream.

peek_code(?N) [ISO]

peek_code(+Stream,?N) [ISO]

N is the character code of the next character peeked at from Stream or from the current input stream.

phrase(:Phrase,?List)

phrase(:Phrase,?List,?Remainder)

Grammar rules. The list List can be parsed as a phrase of type Phrase. The rest of the list is Remainder or empty.

portray(+Term) [Hook]

user:portray(+Term)

Tells print/1 what to do.

portray_clause(?Clause)

portray_clause(+Stream,?Clause)

Pretty prints Clause on the stream Stream or on the current output stream.

portray_message(+Severity,+Message) [Hook]

user:portray_message(+Severity,+Message)

Tells print_message/2 what to do.

predicate_property(:Head,?Prop)

predicate_property(-Head,?Prop)

Head is the most general goal of a currently defined predicate that has the property Prop.

print(?Term) [Hookable]

print(+Stream,?Term) [Hookable]

Portrays or else writes the term Term on the stream Stream or on the current output stream.

print_message(+Severity,+Message) [Hookable]

Portrays or else writes Message of a given Severity on the standard error stream.

print_message_lines(+Stream, +Severity, +Lines)

Print the Lines to Stream, preceding each line with a prefix defined by Severity.

profile_data(:Spec,?Selection,?Resolution,-Data)

Data is the profiling data collected from the instrumented predicates covered by Spec with selection and resolution Selection and Resolution respectively (not available in runtime systems).

profile_reset(:Spec)

The profiling counters for the instrumented predicates covered by Spec are zeroed (not available in runtime systems).

prolog_flag(?FlagName,?Value)

Value is the current value of FlagName.

prolog_flag(+FlagName,?OldValue,?NewValue)

OldValue and NewValue are the old and new values of FlagName.

prolog_load_context(?Key,?Value)

Value is the value of the compilation/loading context variable identified by Key.

prompt(?Old,?New)

Changes the prompt from Old to New.

public Specs [Declaration,obsolescent]

Not a built-in predicate; public declaration.

put(+C) [Obsolescent]

put(+Stream,+C) [Obsolescent]

The next character code sent to the stream Stream or to the current output stream is C.

put_byte(+B) [ISO]

put(+Stream,+B) [ISO]

The next byte sent to the binary stream Stream or to the current output stream is B.

put_char(+C) [ISO]

put_char(+Stream,+C) [ISO]

The next one-char atom sent to the text stream Stream or to the current output stream is C.

put_code(+C) [ISO]

put_code(+Stream,+C) [ISO]

The next character code sent to the text stream Stream or to the current output stream is C.

query_hook(+QueryClass, +Query, +QueryLines, +Help, +HelpLines, -Answer) [Hook]

user:query_hook(+QueryClass, +Query, +QueryLines, +Help, +HelpLines, -Answer)

Called by ask_query/4 before processing the query. If this predicate succeeds, it is assumed that the query has been processed and nothing further is done.

query_class_hook(+QueryClass, -Prompt, -InputMethod, -MapMethod, -FailureMode) [Hook]

user:query_class_hook(+QueryClass, -Prompt, -InputMethod, -MapMethod, -FailureMode)

Provides the user with a method of overriding the call to 'SU_messages':query_class/5 in the preparation phase of query processing. This way the default query class characteristics can be changed.

query_input_hook(+InputMethod, +Prompt, -RawInput) [Hook]

user:query_input_hook(+InputMethod, +Prompt, -RawInput)

Provides the user with a method of overriding the call to 'SU_messages':query_input/3 in the input phase of query processing. This way the implementation of the default input methods can be changed.

query_map_hook(+MapMethod, +RawInput, -Result, -Answer) [Hook]

user:query_map_hook(+MapMethod, +RawInput, -Result, -Answer)

Provides the user with a method of overriding the call to 'SU_messages':query_map/4 in the mapping phase of query processing. This way the implementation of the default map methods can be changed.

raise_exception(+Exception)

Causes the abortion of a part of the execution tree scoped by the closest enclosing catch/3 or on_exception/3 invocation with its first argument matching Exception.

read(?Term) [ISO]

read(+Stream,?Term) [ISO]

Reads the term Term from the stream Stream or from the current input stream.

read_term(?Term,+Options) [ISO]

read_term(+Stream,?Term,+Options) [ISO]

Reads the term Term from the stream Stream or from the current input stream with extra Options.

reconsult(:Files) [Obsolescent]

Updates the program with interpreted clauses from file(s) Files.

recorda(+Key,?Term,-Ref) [Obsolescent]

Makes the term Term the first record under key Key with unique identifier Ref.

recorded(?Key,?Term,?Ref) [Obsolescent]

The term Term is currently recorded under key Key with unique identifier Ref.

recordz(+Key,?Term,-Ref) [Obsolescent]

Makes the term Term the last record under key Key with unique identifier Ref.

reinitialise

Initializes Prolog (returns to C in recursive calls to Prolog from C).

remove_breakpoints(+BIDs)

Removes the breakpoints specified by BIDs. (Not available in runtime systems).

repeat [ISO]

Succeeds repeatedly.

require(:PredSpecs)

Tries to locate and load library files that export the specified predicates. Creates index files if necessary (not available in runtime systems).

restore(+File)

Restores the state saved in file File.

retract(:Clause) [ISO]

Erases repeatedly the next interpreted clause of form Clause.

retractall(:Head)

Erases all clauses whose head matches Head.

runtime_entry(+Message) [Hook]

user:runtime_entry(+Message)

The entry point of most runtime systems. Will be called with Message = start.

save_program(+File)

save_program(+File, :Goal)

Saves the current state of the Prolog data base in file File. Upon restore, Goal is executed.

save_modules(+Modules, +File)

Saves the current contents of the given Modules in the file File.

save_predicates(:Preds, +File)

Saves the current definitions of the given Preds in the file File.

save_files(+SourceFiles, +File)

Saves the modules, predicates and clauses and directives in the given SourceFiles in the file File.

see(+File)

Makes file File the current input stream.

seeing(?File)

The current input stream is named File.

seek(+Stream,+Offset,+Method,-NewLocation)

Sets the stream Stream to the byte offset Offset relative to Method, and NewLocation is the new byte offset from the beginning of the file after the operation.

seen

Closes the current input stream.

set_input(+Stream) [ISO]

Sets the current input stream to Stream.

set_output(+Stream) [ISO]

Sets the current output stream to Stream.

set_prolog_flag(+FlagName,?NewValue) [ISO]

NewValue becomes the new value of FlagName.

set_stream_position(+Stream,+Position) [ISO]

Position is a new stream position of Stream, which is then set to the new position.

setof(?Template,:Goal,?Set) [ISO]

Set is the set of instances of Template such that Goal is satisfied (not just provable).

simple(?X)

X is currently uninstantiated or atomic.

skip(+C) [Obsolescent]

skip(+Stream,+C) [Obsolescent]

Skips characters from Stream or from the current input stream until after character C.

skip_line

skip_line(+Stream)

Skips characters from Stream or from the current input stream until the next <LFD>.

sort(+List1,?List2)

The list List1 sorted into order yields List2.

source_file(?File)

source_file(:Pred,?File)

source_file(-Pred,?File)

The predicate Pred is defined in the file File.

spy :Spec

Sets spypoints on the predicate(s) specified by Spec (not available in runtime systems).

spy(:Spec, :Conditions)

Sets spypoints with condition Conditions on the predicates specified by Spec (not available in runtime systems).

statistics

Outputs various execution statistics.

statistics(?Key,?Value)

The execution statistics key Key has value Value.

stream_code(+Stream,?StreamCode)

stream_code(?Stream,+StreamCode)

StreamCode is an integer representing a pointer to the internal representation of Stream.

stream_position(+Stream,?Position)

Position is the current stream position of Stream.

stream_position_data(?Field,?Position,?Data)

The Field field of the stream position Pos term is Data.

stream_property(?Stream, ?Property)) [ISO]

Stream Stream has property Property.

sub_atom(+Atom,?Before,?Length,?After,?SubAtom) [ISO]

The characters of SubAtom form a sublist of the characters of Atom, such that the number of characters preceding SubAtom is Before, the number of characters after SubAtom is After, and the length of SubAtom is Length.

tab(+N) [Obsolescent]

tab(+Stream,+N) [Obsolescent]

Outputs N spaces to the stream Stream or to the current output stream.

tell(+File)

Makes file File the current output stream.

telling(?File)

The current output stream is named File.

term_expansion(+Term1,?TermOrTerms) [Hook]

term_expansion(+Term1,+Layout1,?TermOrTerms,?Layout2) [Hook]

user:term_expansion(+Term1,?TermOrTerms)

user:term_expansion(+Term1,+Layout1,?TermOrTerms,?Layout2)

Tell expand_term/2 what to do.

throw(+Exception) [ISO]

Causes the abortion of a part of the execution tree scoped by the closest enclosing catch/3 or on_exception/3 invocation with its first argument matching Exception.

told

Closes the current output stream.

trace

Switches on debugging in creep mode (not available in runtime systems).

trimcore

Reclaims and defragmentizes unused memory.

true [ISO]

Succeeds.

ttyflush [Obsolescent]

Flushes the standard output stream buffer.

ttyget(?C) [Obsolescent]

The next printing character input from the standard input stream is C.

ttyget0(?C) [Obsolescent]

The next character input from the standard input stream is C.

ttynl [Obsolescent]

Outputs a new line on the standard output stream.

ttyput(+C) [Obsolescent]

The next character output to the standard output stream is C.

ttyskip(+C) [Obsolescent]

Skips characters from the standard input stream until after character C.

ttytab(+N) [Obsolescent]

Outputs N spaces to the standard output stream.

undo(:Goal)

Goal is called on backtracking.

unify_with_occurs_check(?X, ?Y) [ISO]

True if X and Y unify to a finite (acyclic) term.

unknown(?OldState,?NewState)

Changes action on undefined predicates from OldState to NewState (not available in runtime systems).

unknown_predicate_handler(+Goal,+Module,-NewGoal) [Hook]

user:unknown_predicate_handler(+Goal,+Module,-NewGoal)

Defines an alternative goal to be called in place of a call to an unknown predicate.

unload_foreign_resource(:Resource)

Unloads foreign resource Resource from Prolog.

update_mutable(+Datum,+Mutable)

Updates the current value of the mutable term Mutable to become Datum.

use_module(:Files)

Loads the module-file(s) Files if necessary and imports all public predicates.

use_module(:File,+Imports)

Loads the module-file File if necessary and imports the predicates in Imports.

use_module(+Module,?File,+Imports)

use_module(?Module,:File,+Imports)

Imports Imports from an existing Module, or else the same as use_module/2 unifying Module to the module defined in File.

user_help [Hook]

user:user_help

Tells help/0 what to do.

var(?X) [ISO]

X is currently uninstantiated.

version

Displays introductory and/or system identification messages (not available in runtime systems).

version(+Message)

Adds the atom Message to the list of introductory messages (not available in runtime systems).

volatile Specs [Declaration]

Not a built-in predicate; volatile declaration.

when(+Condition,:Goal)

Blocks Goal until the Condition is true.

write(+Term) [ISO]

write(+Stream,+Term) [ISO]

Writes the term Term on the stream Stream or on the current output stream.

write_canonical(+Term) [ISO]

write_canonical(+Stream,+Term) [ISO]

Writes Term on the stream Stream or on the current output stream so that it may be read back.

write_term(+Term,+Options) [ISO]

write_term(+Stream,+Term,+Options) [ISO]

Writes the term Term on the stream Stream or on the current output stream with extra Options.

writeq(+Term) [ISO]

writeq(+Stream,+Term) [ISO]

Writes the term Term on the stream Stream or on the current output stream, quoting names where necessary.

zip

Switches on debugging in zip mode (not available in runtime systems).