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
X and Y are unified.
+Term =.. ?List ISO
?Term =.. +List ISO
The functor and arguments of Term comprise the list List.
+X =:= +Y ISO
X is numerically equal to Y.
?Term1 == ?Term2 ISO
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
Term1 and Term2 are not strictly identical.
+X < +Y ISO
X is less than Y.
?Term1 @=< ?Term2 ISO
Term1 precedes or is identical to Term2 in the standard order.
?Term1 @> ?Term2 ISO
Term1 follows Term2 in the standard order.
?Term1 @>= ?Term2 ISO
Term1 follows or is identical to Term2 in the standard order.
?Term1 @< ?Term2 ISO
Term1 precedes 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) development
Creates a breakpoint with Conditions and with identifier BID.
arg(+ArgNo,+Term,?Arg) ISO,meta-logical
The argument ArgNo of 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,meta-logical
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 char-list CharList.
atom_chars(+Atom,?CodeList) SICStus only
atom_chars(?Atom,+CodeList) SICStus only
The name of the atom Atom is the code-list CodeList.
atom_codes(+Atom,?CodeList) ISO
atom_codes(?Atom,+CodeList) ISO
The name of the atom Atom is the code-list 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,meta-logical
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 Term under Key on the blackboard.
bb_update(:Key, ?OldTerm, ?NewTerm)
Replace OldTerm by NewTerm under Key on the blackboard.
break development
Invokes a recursive top-level.
breakpoint_expansion(+Macro, -Body) hook,development
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 determinately, 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) meta-logical
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 Term1 and Term2.
compile(:Files)
Compiles in-core the clauses in text file(s) Files.
compound(?X) ISO,meta-logical
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,meta-logical
CopyOfTerm is an independent copy of Term.
create_mutable(+Datum,-Mutable)
Mutable is a new mutable term with current value Datum.
current_atom(?Atom) meta-logical
One of the currently defined atoms is Atom.
current_breakpoint(:Conditions, ?BID, ?Status, ?Kind, ?Type) development
There is a breakpoint with conditions Conditions, identifier BID, enabledness Status, kind Kind, and type Type.
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 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 development
Switches on debugging in debug mode.
debugger_command_hook(+DCommand,?Actions) hook,development
user:debugger_command_hook(+DCommand,?Actions)
Allows the interactive debugger to be extended with user-defined commands.
debugging development
Displays debugging status information
dif(?X,?Y)
X and Y are different.
disable_breakpoints(+BIDs) development
Disables the breakpoints specified by BIDs.
discontiguous Specs declaration,ISO
Not a built-in predicate; discontiguous declaration.
display(?Term)
Displays Term on the standard output stream.
dynamic Specs declaration,ISO
Not a built-in predicate; dynamic declaration.
enable_breakpoints(+BIDs) development
Enables the breakpoints specified by BIDs.
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) development
Tests are satisfied in the current state of the execution.
execution_state(+FocusConditions, :Tests) development
Tests are satisfied in the state of the execution pointed to by FocusConditions.
expand_term(+Term1,?Term2)
Term1 is a shorthand expanding to Term2.
fail ISO
false
False.
fcompile(:Files) development,obsolescent
Compiles file-to-file the clauses in text file(s) Files.
file_search_path(Path,?Expansion) hook
user:file_search_path(Path,?Expansion)
Tells how to expand Path(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,meta-logical
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 foreign 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,meta-logical
functor(?Term,+Name,+Arity) ISO,meta-logical
The principal functor of 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) meta-logical
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,development
Prints a help message.
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 that 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,meta-logical
X is currently instantiated to an integer.
?Y is +X ISO
Y is the value of the arithmetic expression X.
is_mutable(?X) meta-logical
X is currently instantiated to a mutable term.
keysort(+List1,?List2)
The list List1 sorted by key yields List2.
leash(+Mode) development
Sets leashing mode to Mode.
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.
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) development,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 development
Switches off debugging.
nofileerrors
Disables reporting of file errors.
nogc
Disables garbage collection of the global stack.
nonvar(?X) ISO,meta-logical
X is a non-variable.
nospy :Spec development
Removes spypoints from the predicate(s) specified by Spec.
nospyall development
Removes all spypoints.
notrace development
nozip development
Switches off debugging.
number(?X) ISO,meta-logical
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 code-list CodeList.
number_chars(+Number,?CharList) ISO only
number_chars(?Number,+CharList) ISO only
The name of the number Number is the char-list CharList.
number_codes(+Number,?CodeList) ISO
number_codes(?Number,+CodeList) ISO
The name of the number Number is the code-list CodeList.
numbervars(?Term,+N,?M) meta-logical
Number the variables in 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 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) development
Data is the profiling data collected from the instrumented predicates covered by Spec with selection and resolution Selection and Resolution respectively.
profile_reset(:Spec) development
The profiling counters for the instrumented predicates covered by Spec are zeroed.
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 Term from the stream Stream or from the current input stream.
read_term(?Term,+Options) ISO
read_term(+Stream,?Term,+Options) ISO
Reads 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 Term the first record under key Key with unique identifier Ref.
recorded(?Key,?Term,?Ref) obsolescent
Term is currently recorded under key Key with unique identifier Ref.
recordz(+Key,?Term,-Ref) obsolescent
Makes Term the last record under key Key with unique identifier Ref.
remove_breakpoints(+BIDs) development
Removes the breakpoints specified by BIDs.
repeat ISO
Succeeds repeatedly.
require(:PredSpecs) development
Tries to locate and load library files that export the specified predicates. Creates index files if necessary.
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 database 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) meta-logical
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 development
Sets spypoints on the predicate(s) specified by Spec.
spy(:Spec, :Conditions) development
Sets spypoints with condition Conditions on the predicates specified by Spec.
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 term Position 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 development
Switches on debugging in trace mode.
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) development
Changes action on undefined predicates from OldState to NewState.
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,meta-logical
X is currently uninstantiated.
version development
Displays introductory and/or system identification messages.
version(+Message) development
Adds the atom Message to the list of introductory messages.
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 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 Term on the stream Stream or on the current output stream with extra Options.
writeq(+Term) ISO
writeq(+Stream,+Term) ISO
Writes Term on the stream Stream or on the current output stream, quoting names where necessary.
zip development
Switches on debugging in zip mode.