Basic term manipulation

Author(s): Daniel Cabeza, Manuel Hermenegildo.

Version: 1.11#222 (2004/5/24, 13:8:7 CEST)

Version of last change: 1.11#170 (2004/2/3, 21:41:49 CET)

This module provides basic term manipulation.

• Usage and interface (term_basic)
• Documentation on exports (term_basic)

Usage and interface (term_basic)

Documentation on exports (term_basic)

PREDICATE: =/2:

Usage: X = Y * ISO *

• Description: X and Y unify.
• The following properties hold globally: X=Y is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1) basic_props:eval(X=Y) (basic_props:eval/1)

PREDICATE: arg/3:

Usage: arg(ArgNo, Term, Arg) * ISO *

• Description: Argument ArgNo of the term Term is Arg.
• The following properties should hold at call time: ArgNo is currently a term which is not a free variable. (term_typing:nonvar/1) Term is currently a term which is not a free variable. (term_typing:nonvar/1) ArgNo is an integer. (basic_props:int/1)
• The following properties hold globally: arg(ArgNo,Term,Arg) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1) basic_props:eval(arg(ArgNo,Term,Arg)) (basic_props:eval/1)

PREDICATE: functor/3:

Usage 1: functor(Term, Name, Arity) * ISO *

• Description: The principal functor of the term Term has name Name and arity Arity.
• The following properties hold upon exit: Name is an atom. (basic_props:atm/1) Arity is a number. (basic_props:num/1)
• The following properties hold globally: functor(Term,Name,Arity) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

Usage 2: functor(Term, Name, Arity)

• The following properties should hold at call time: Term is currently a term which is not a free variable. (term_typing:nonvar/1)
• The following properties hold globally: basic_props:eval(functor(Term,Name,Arity)) (basic_props:eval/1)

Usage 3: functor(Term, Name, Arity)

• The following properties should hold at call time: Name is currently a term which is not a free variable. (term_typing:nonvar/1) Arity is currently a term which is not a free variable. (term_typing:nonvar/1)
• The following properties hold globally: basic_props:eval(functor(Term,Name,Arity)) (basic_props:eval/1)

PREDICATE: =../2:

Usage 1: Term =.. List * ISO *

• Description: The functor and arguments of the term Term comprise the list List.
• The following properties hold upon exit: List is a list. (basic_props:list/1)
• The following properties hold globally: Term=..List is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

Usage 2: Term =.. List

• The following properties should hold at call time: Term is currently a term which is not a free variable. (term_typing:nonvar/1)
• The following properties hold globally: basic_props:eval(Term=..List) (basic_props:eval/1)

Usage 3: Arg1 =.. List

• The following properties should hold at call time: List is a list. (basic_props:list/1) term_basic:atom_head(List) (term_basic:atom_head/1)
• The following properties hold globally: basic_props:eval(Arg1=..List) (basic_props:eval/1)

PREDICATE: copy_term/2:

Usage: copy_term(Term, Copy) * ISO *

• Description: Copy is a renaming of Term, such that brand new variables have been substituted for all variables in Term. If any of the variables of Term have attributes, the copied variables will have copies of the attributes as well. It behaves as if defined by:

  :- data 'copy of'/1.
  
  copy_term(X, Y) :-
          asserta_fact('copy of'(X)),
          retract_fact('copy of'(Y)).
  

• The following properties hold globally: copy_term(Term,Copy) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: C/3:

Usage: C(S1, Terminal, S2)

• Description: S1 is connected by the terminal Terminal to S2. Internally used in DCG grammar rules. Defined as if by the single clause: 'C'([X|S], X, S).
• The following properties hold globally: C(S1,Terminal,S2) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

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