Prolog/Built-in predicates

List of built-in predicates in ISO Prolog.

Term unification

=/2

Prolog unification

unify_with_occurs_check/2

(\=)/2

Not Prolog unifiable

Type testing

var/1

True if term currently is a variable

atom/1

True if term is bound to an atom

integer/1

True if term is bound to an integer

float/1

True if term is bound to a floating point number

atomic/1

True if term is bound to an atom, integer or floating point number

compound/1

True if term is bound to a compound term

nonvar/1

True if term is not a variable

number/1

True if term is bound to an integer or floating point number

Term comparison

(@=<)/2

Term less than or equal to

(==)/2

Term identical

(\==)/2

Term not identical

(@<)/2

Term less than

(@>)/2

Term greater than

(@>=)/2

Term greater than or equal to

Term creation and decomposition

functor/3

arg/3

(=../2)

copy_term/2

Arithmetic evaluation

is/2

Arithmetic comparison

'=:='/2

Arithmetic equal

'=\='/2

Arithmetic not equal

'<'/2

Arithmetic less than

'=<'/2

Arithmetic less than or equal to

'>'/2

Arithmetic greater than

'>='/2

Arithmetic greater than or equal to

Clauses

Clause retrieval and information

clause/2

current_predicate/1

Clause creation and destruction

asserta/1

assertz/1

retract/1

abolish/1

All solutions

findall/3

bagof/3

setof/3

Input and output

Stream selection and control

current_input/1

current_output/1

set_input/1

set_output/1

open/4, open/3

Opening a stream

close/1, close/2

Closing a stream

stream_property/2

at_end_of_stream/1, at_end_of_stream/0

set_stream_position/2

Character input-output

get_char/2, get_char/1

get_code/2, get_code/1

peek_char/2, peek_char/1

peek_code/2, peek_code/1

put_char/2, put_char/1

put_code/2, put_code/1

nl/0, nl/1

Reading from binary streams

get_byte/2, get_byte/1

peek_byte/2, peek_byte/1

put_byte/2, put_byte/1

Term input and output

read_term/2, read_term/3

read/1, read/2

Writing terms

write_term/3, write_term/2

write/1, write/2

writeq/1, writeq/2

write_canonical/1, write_canonical/2

Operators

op/3

current_op/3

Character conversion

char_conversion/2

current_char_conversion/2

Logic and control

(\+)/1

Not provable

once/1

repeat/0

Atom processing

atom_length/2

atom_concat/3

sub_atom/5

atom_chars

atom_codes/2

char_code/2

number_chars/2

number_codes/2

Implementation defined hooks

set_prolog_flag/2

current_prolog_flag/2

halt/0, halt/1

Functors

Evaluable functors

(+)/2

Addition

(-)/2

Subtraction

(*)/2

Multiplication

(//)/2

Integer division

(/)/2

Division

(rem)/2

Remainder

(mod)/2

Modulus

(-)/1

Negation

(abs)/1

Absolute value

(sign)/1

Sign

(float_integer_part)/1

Integer part

(float_fractional_part)/1

Fractional part

(float)/1

Float coercion

(floor)/1

Floor

(truncate)/1

Truncate

(round)/1

Round

(ceiling)/1

Ceiling

Other arithmetic and bitwise functors

(**)/2

Power

sin/1

Sine

cos/1

Cosine

atan/1

Arc tangent

exp/1

Exponentiation

log/1

Log

sqrt/1

Square root

(>>)/2

Bitwise right shift

(<<)/2

Bitwise left shift

(/\)/2

Bitwise and

(\/)/2

Bitwise or

(\)/1

Bitwise complement