Tau Prolog: Documentation

Prolog Predicate Reference

Built-in predicates Lists module DOM module Random module Statistics module JavaScript module OS module Format module CharsIO module Concurrent module

Built-in predicates

Control Constructs

!/0 – Cut.
,/2 – Conjunction.
->/2 – If-Then.
->;/3 – If-Then-Else.
;/2 – Disjunction.
call/1 – Invoke a callable term as a goal.
call/2 – Invoke a callable term as a goal with an extra argument.
call/3 – Invoke a callable term as a goal with two extra arguments.
call/4 – Invoke a callable term as a goal with three extra arguments.
call/5 – Invoke a callable term as a goal with four extra arguments.
call/6 – Invoke a callable term as a goal with five extra arguments.
call/7 – Invoke a callable term as a goal with six extra arguments.
call/8 – Invoke a callable term as a goal with seven extra arguments.
call_cleanup/2 –
catch/3 – Enable recovery from exceptions.
fail/0 – Always fail.
false/0 – Always fail.
setup_call_cleanup/3 –
throw/1 – Raise an exception.
true/0 – Always succeed.

Term Unification

=/2 – Unification.
subsumes_term/2 – Checks if general term can be made equivalent to specific one.
unify_with_occurs_check/2 – Check if two terms are unifiable.
\=/2 – Not unification.

Clause Creation and Destruction

abolish/1 – Remove all the clauses of a predicate.
asserta/1 – Add term to the Prolog database.
assertz/1 – Add term to the Prolog database.
retract/1 – Delete term from Prolog database.
retractall/1 – Removes rules and clauses which unify with a term.

Clause Retrieval and Information

clause/2 – Check the existence of rules.
current_module/1 –
current_predicate/1 – Check the existence of predicates.
listing/0 – List predicates defined in the calling module.
listing/1 – List predicates defined in the calling module.
predicate_property/2 –

Term Creation and Decomposition

=../2 – Check the decomposition of a term.
arg/3 – Check the argument of a term in the nth position.
copy_term/2 – Copy one term without bounding the variables on it.
functor/3 – Check characteristics of a term.
numbervars/3 –
term_variables/2 – Get variables of term.
term_variables/3 – Get variables of term.

Term Comparison

==/2 – Term identical.
@</2 – Term less than.
@=</2 – Term less than or equal to.
@>/2 – Term greater than.
@>=/2 – Term greater than or equal to.
compare/3 – Compare two terms according to order.
\==/2 – Term not identical.

Type Testing

acyclic_term/1 – Check if term has no cycles.
atom/1 – Check if atom.
atomic/1 – Check if atom, integer or float.
callable/1 – Check if term is callable.
compound/1 – Check if compound.
float/1 – Check if float.
ground/1 – Check if term has no free variables.
integer/1 – Check if integer.
is_list/1 – Check if list.
nonvar/1 – Check if not variable.
number/1 – Check if integer or float.
var/1 – Check if variable.

Logic and Control

once/1 – Evaluate a term just once.
repeat/0 – Provide infinite choice points.
\+/1 – Not provable.

Atom Processing

atomic_list_concat/2 – Concatenate elements of list.
atomic_list_concat/3 – Concatenate elements of list with atom.
atom_chars/2 – Express an atom as a list of one character atoms.
atom_codes/2 – Express an atom as a list of character codes.
atom_concat/3 – Concatenate characters.
atom_length/2 – Length of an atom.
char_code/2 – Character code of an atom.
downcase_atom/2 – Turn atom into lowercase.
number_chars/2 – Express a number as a list of one character atoms.
number_codes/2 – Express a number as a list of number codes.
sub_atom/5 – Look for subatoms inside an atom.
upcase_atom/2 – Turn atom into uppercase.

All Solutions

bagof/3 – Find all the values that would make a goal succeed and structure them.
findall/3 – Find all the values that would make a goal succeed.
findall/4 – Find all the values that would make a goal succeed.
forall/2 – Check an action for all alternative bindings.
setof/3 – Find all the values that would make a goal succeed and organize and order them.

Arithmetic Evaluation

between/3 – Check if value is within a range of integers.
is/2 – Evaluate expression.
succ/2 – Return the successor of a positive number.

Arithmetic Comparison

</2 – Arithmetic less than.
=:=/2 – Arithmetic equal.
=</2 – Arithmetic less than or equal to.
=\=/2 – Arithmetic not equal.
>/2 – Arithmetic greater than.
>=/2 – Arithmetic greater than or equal to.

Implementation defined hooks

current_prolog_flag/2 – Check prolog flag and flag values.
halt/0 – Terminate a Prolog processor.
halt/1 – Terminate a Prolog processor and return message.
set_prolog_flag/2 – Set value of flag.

Input and Output

current_op/3 – Check properties of operator.
op/3 – Alter the operator table.

Stream Selection and Control

at_end_of_stream/0 – Check if last character from current input stream has been read.
at_end_of_stream/1 – Check if last character from a specific input stream has been read.
close/1 – Close a stream.
close/2 – Close a stream according to several options.
current_input/1 – Get the current input stream.
current_output/1 – Get the current output stream.
flush_output/0 – Flush output on current stream.
flush_output/1 – Flush output on specified stream.
open/3 – Open a source in a certain mode through a stream.
open/4 – Open a source in a certain mode through a stream according to some options.
set_input/1 – Set the current input stream.
set_output/1 – Set the current output stream.
set_stream_position/2 – Set the stream position.
stream_position_data/3 –
stream_property/2 – Retrieve stream properties.

Character Input/Output

get_char/1 – Get character from current input stream.
get_char/2 – Get character from input stream.
get_code/1 – Get character code from current input stream.
get_code/2 – Get character code from input stream.
nl/0 – Write new line character to current output stream.
nl/1 – Write new line character to output stream.
peek_char/1 – Read character from current input stream without removing it.
peek_char/2 – Read character from input stream without removing it.
peek_code/1 – Read character code from current input stream without removing it.
peek_code/2 – Read character code from input stream without removing it.
put_char/1 – Write character in current output stream.
put_char/2 – Write character in output stream.
put_code/1 – Write character code in current output stream.
put_code/2 – Write character code in output stream.

Byte Input/Output

get_byte/1 – Read byte from current input stream.
get_byte/2 – Read byte fom input stream.
peek_byte/1 – Read byte from current input stream without removing it.
peek_byte/2 – Read byte from input stream without removing it.
put_byte/1 – Write byte in current output stream.
put_byte/2 – Write byte in output stream.

Term Input/Output

read/1 – Read Prolog term from current input stream.
read/2 – Read Prolog term from input stream.
read_term/2 – Read Prolog term from current input stream according to some options.
read_term/3 – Read Prolog term from input stream according to some options.
write/1 – Write Prolog term to current output stream.
write/2 – Write Prolog term to output stream.
writeq/1 – Write Prolog term to current output stream, quoting atoms if necessary.
writeq/2 – Write Prolog term to output stream, quoting atoms if necessary.
write_canonical/1 – Write Prolog term to current output stream in canonical form.
write_canonical/2 – Write Prolog term to output stream in canonical form.
write_term/2 – Write Prolog term into current output stream according to some options.
write_term/3 – Write Prolog term into output stream according to some options.

Grammars

phrase/2 – Safely execute a grammar rule from a predicate clause.
phrase/3 – Safely execute a grammar rule from a predicate clause.

Term and Goal Expansion

goal_expansion/2 – Rewrite Prolog code at compile time.
term_expansion/2 – Rewrite Prolog code at compile time.

Time and Date

get_time/1 –
time_property/2 –

Built-in List Operations

keysort/2 – Check keys order.
sort/2 – Checks standard order.

Lists module

:- use_module(library(lists)).

List Manipulation

append/2 – Concatenate a list of lists.
append/3 – Join two lists.
drop/3 – Drop the first elements of a list.
last/2 – Last element of a list.
length/2 – Length of a list.
list_to_set/2 – Turn list into set.
max_list/2 – Largest element of a list.
member/2 – Check membership of element in list.
min_list/2 – Smallest element of a list.
msort/2 – Check standard order.
nth0/3 – Get the Nth element of a list.
nth0/4 – Get the Nth element of a list and the rest of elements on it.
nth1/3 – Get the Nth element of a list.
nth1/4 – Get the Nth element of a list and the rest of elements on it.
permutation/2 – Permutation of list.
prefix/2 – Get prefixes of list.
prod_list/2 – Product of the elements of a list.
replicate/3 – Generate list by replicating an element.
reverse/2 – Invert the order of the elements in a list.
select/3 – Check if two lists differ in one element.
take/3 – Retrieve first elements of a list.

Higher Order

exclude/3 – Filter elements for which a goal fails.
foldl/4 – Reduce list to a single value.
include/3 – Filter elements for which a goal succeeds.
maplist/2 – Check if goal can be applied to a list.
maplist/3 – Check if goal can be applied to several lists.
maplist/4 – Check if goal can be applied to several lists.
maplist/5 – Check if goal can be applied to several lists.
maplist/6 – Check if goal can be applied to several lists.
maplist/7 – Check if goal can be applied to several lists.
maplist/8 – Check if goal can be applied to several lists.

DOM module

:- use_module(library(dom)).

DOM Manipulation

add_class/2 – Add class to an HTML element.
append_child/2 – Insert an HTML element at the end of another.
attr/3 – Read or update an attribute of an HTML element.
body/1 – Get the body of the page.
create/2 – Create an HTML element or check its tag name.
document/1 – Get the document object.
get_attr/3 – Get attribute value from HTML object.
get_by_class/2 – Get HTML elements with the same class.
get_by_class/3 – Get HTML elements with the same class under a parent object.
get_by_id/2 – Get an HTML element by its id.
get_by_name/2 – Get HTML elements by their names.
get_by_tag/2 – Get HTML elements with the same tag.
get_by_tag/3 – Get HTML elements with the same tag under a parent object.
get_html/2 – Get the HTML inside of an HTML element.
get_style/3 – Get the CSS property of an HTML element.
has_class/2 – Check if an HTML element has a certain class.
head/1 – Get the header of the page.
html/2 – Read or update an HTML element.
insert_after/2 – Insert an HTML element after another.
insert_before/2 – Insert an HTML element before another.
parent_of/2 – Get HTML parent of an HTML element.
prepend_child/2 – Insert an HTML element at the beginning of another.
remove/1 – Remove an HTML element.
remove_class/2 – Delete a class from an HTML element.
set_attr/3 – Set attribute value for HTML object.
set_html/2 – Set the HTML of an HTML element.
set_style/3 – Set the CSS property of an HTML element.
sibling/2 – Get an HTML element's sibling.
style/3 – Read or update a CSS property of an HTML element.

Events

bind/4 – Bind a certain event to an HTML element.
event_property/3 – Extract a property's value of an event.
prevent_default/1 – Prevent default behaviour in an event.
unbind/2 – Unbind event linked to an HTML element.
unbind/3 – Unbind events linked to an HTML element which execute a certain goal.

Effects

hide/1 – Hide an HTML element.
show/1 – Show an HTML element.
toggle/1 – Toggle an HTML visibility.

Random module

:- use_module(library(random)).

Random Numbers

get_seed/1 –
maybe/0 – Succeed or fail randomly.
maybe/1 – Succeed or fail with a certain probability.
random/1 – Generate random value.
random/3 – Generate random value in a range.
random_between/3 – Get random integer from range.
random_member/2 – Get random element of list.
random_permutation/2 – Rearrange list randomly.
set_seed/1 –

Statistics module

:- use_module(library(statistics)).

Statistic Operations

statistics/0 – Display system statistics.
statistics/2 – Display data of a single statistic.
time/1 – Execute goal and print metrics.

JavaScript module

:- use_module(library(js)).

Invoking JavaScript Functions

apply/3 – Invoke a JavaScript global function with a list of arguments.
apply/4 – Invoke a JavaScript function with a list of arguments.
global/1 – Get the global JavaScript object.
json_atom/2 – Transform a JavaScript object into a Prolog atom.
json_prolog/2 – Transform a JavaScript object into a Prolog list.
new/3 – Create an instance of a JavaScript object.
prop/2 – Get a property of the JavaScript global object.
prop/3 – Get a property of a JavaScript object.

AJAX Requests

ajax/3 – Perform an asynchronous HTTP (Ajax) request.
ajax/4 – Perform an asynchronous HTTP (Ajax) request.

OS module

:- use_module(library(os)).

Operating System Interaction

sleep/1 – Suspend execution.
absolute_file_name/2 – Expand a local filename into an absolute path.
delete_directory/1 – Remove a directory.
delete_file/1 – Remove a file.
directory_files/2 – Get the list of files in a directory.
exists_directory/1 – Check the existence of a directory.
exists_file/1 – Check the existence of a file.
file_permission/2 –
is_absolute_file_name/1 – Check if absolute path name.
make_directory/1 – Create a directory.
pid/1 –
rename_file/2 – Rename a file.
same_file/2 – Check if two files are the same.
shell/1 – Run a shell command.
shell/2 – Run a shell command.
size_file/2 – Get the size of a file.
time_file/2 – Last modified time of a file.
working_directory/2 – Get and update the current working directory.

Format module

:- use_module(library(format)).

Formatted Write

format/2 – Output a formatted string.
format/3 – Output a formatted string.
format_/4 – Describe a formatted string.

CharsIO module

:- use_module(library(charsio)).

I/O on Lists of Characters

write_term_to_chars/3 – Write Prolog term to a list of characters.

Concurrent module

:- use_module(library(concurrent)).

Asynchronous execution with futures

await/2 – Wait for a Future.
future/3 – Make a Future from a Prolog goal.
future_all/2 – Make a Future that resolves to a list of the results of an input list of futures.
future_any/2 – Make a Future that resolves as soon as any of the futures in a list succeeds.
future_done/1 – Check if a future finished.

Documentation

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