Inlined Tests and Term Manipulation

Detailed Description

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Class Documentation

fail/0

class fail/0

fail

defined in the ISO standard

Always fails Defined as if by:

fail :- 2=1.

false/0

class false/0

false

defined in the ISO standard

The same as fail Defined as if by:

false :- 2=1.

true/0

class true/0

true

defined in the ISO standard

Succeed

Succeeds once Defined as if by:

true :- true.

otherwise/0

class otherwise/0

otherwise

defined in the ISO standard

Succeed

Succeeds once Defined as if by:

otherwise.

atom/1

class atom/1

atom( T)

defined in the ISO standard

Succeeds if and only if T is currently instantiated to an atom

atomic/1

class atomic/1

atomic(T)

defined in the ISO standard

Checks whether T is an atomic symbol (atom or number)

integer/1

class integer/1

integer( T)

defined in the ISO standard

Succeeds if and only if T is currently instantiated to an integer

number/1

class number/1

number( T)

defined in the ISO standard

Checks whether T is an integer, rational or a float

db_reference/1

class db_reference/1

db_reference( T)

Checks whether T is a database reference

primitive/1

class primitive/1

primitive( ?_T_)

Checks whether T is an atomic term or a database reference

float/1

class float/1

float( T)

defined in the ISO standard

Checks whether T is a floating point number

compound/1

class compound/1

compound( T)

defined in the ISO standard

Checks whether T is a compound term

nonvar/1

class nonvar/1

nonvar( T)

defined in the ISO standard

The opposite of var( _T_)

var/1

class var/1

var( T)

defined in the ISO standard

Succeeds if T is currently a free variable, otherwise fails

var/2

class var/2

?_X_ == ?_Y_

defined in the ISO standard

Succeeds if terms X and Y are strictly identical The difference between this predicate and =/2 is that, if one of the arguments is a free variable, it only succeeds when they have already been unified

?- X == Y.

fails, but,

?- X = Y, X == Y.

succeeds

?- X == 2.

fails, but,

?- X = 2, X == 2.

succeeds

arg/3

class arg/3

arg(+ N,+ T, A)

defined in the ISO standard

Succeeds if the argument N of the term T unifies with A The arguments are numbered from 1 to the arity of the term

The current version will generate an error if T or N are unbound, if T is not a compound term, of if N is not a positive integer Note that previous versions of YAP would fail silently under these errors

functor/3

class functor/3

functor( T, F, N)

defined in the ISO standard

The top functor of term T is named F and has arity N

When T is not instantiated, F and N must be If N is 0, F must be an atomic symbol, which will be unified with T If N is not 0, then F must be an atom and T becomes instantiated to the most general term having functor F and arity N If T is instantiated to a term then F and N are respectively unified with its top functor name and arity

In the current version of YAP the arity N must be an integer Previous versions allowed evaluable expressions, as long as the expression would evaluate to an integer This feature is not available in the ISO Prolog standard

current_choice_point/1

class current_choice_point/1

current_choice_point( -CP )

unify the logic variable CP with a number that gives the offset of the current choice-point This number is only valid as long as we do not backtrack by or cut CP, and is safe in the presence of stack shifting and/or garbage collection

Macro Definition Documentation

IN_INLINES_C

#define IN_INLINES_C   1

Definition at line 33 of file inlines.c.

Function Documentation

Yap_eq()

int Yap_eq	(	Term	t1,
		Term	t2
	)

Definition at line 571 of file inlines.c.

Macros
#define	IN_INLINES_C   1

Functions
int	Yap_eq (Term t1, Term t2)