Basic predicates handling names of constants

Author(s): The CLIP Group.

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

Version of last change: 1.11#169 (2004/2/3, 21:36:40 CET)

The Ciao system provides builtin predicates which allow dealing with names of constants (atoms or numbers). Note that sometimes strings (character code lists) are more suitable to handle sequences of characters.

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

Usage and interface (atomic_basic)

Documentation on exports (atomic_basic)

PREDICATE: name/2:

name(Const, String)

String is the list of the ASCII codes of the characters comprising the name of Const. Note that if Const is an atom whose name can be interpreted as a number (e.g. '96'), the predicate is not reversible, as that atom will not be constructed when Const is uninstantiated. Thus it is recommended that new programs use the ISO-compliant predicates atom_codes/2 or number_codes/2, as these predicates do not have this inconsistency.

General properties:

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

Usage 1:

• Calls should, and exit will be compatible with: String is a string (a list of character codes). (basic_props:string/1)
• The following properties should hold at call time: Const is an atomic term (an atom or a number). (basic_props:constant/1)
• The following properties hold upon exit: String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold globally: basic_props:eval(name(Const,String)) (basic_props:eval/1)

Usage 2:

• Description: If String can be interpreted as a number, Const is unified with that number, otherwise with the atom whose name is String.
• The following properties should hold at call time: Const is a free variable. (term_typing:var/1) String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold upon exit: Const is an atomic term (an atom or a number). (basic_props:constant/1)
• The following properties hold globally: basic_props:eval(name(Const,String)) (basic_props:eval/1)

PREDICATE: atom_codes/2:

atom_codes(Atom, String) * ISO *

String is the list of the ASCII codes of the characters comprising the name of Atom.

General properties:

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

Usage 1:

• Calls should, and exit will be compatible with: String is a string (a list of character codes). (basic_props:string/1)
• The following properties should hold at call time: Atom is an atom. (basic_props:atm/1)
• The following properties hold upon exit: String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold globally: basic_props:eval(atom_codes(Atom,String)) (basic_props:eval/1)

Usage 2:

• The following properties should hold at call time: Atom is a free variable. (term_typing:var/1) String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold upon exit: Atom is an atom. (basic_props:atm/1)
• The following properties hold globally: basic_props:eval(atom_codes(Atom,String)) (basic_props:eval/1)

PREDICATE: number_codes/2:

number_codes(Number, String) * ISO *

String is the list of the ASCII codes of the characters comprising a representation of Number.

General properties:

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

Usage 1:

• Calls should, and exit will be compatible with: String is a string (a list of character codes). (basic_props:string/1)
• The following properties should hold at call time: Number is a number. (basic_props:num/1)
• The following properties hold upon exit: String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold globally: basic_props:eval(number_codes(Number,String)) (basic_props:eval/1)

Usage 2:

• The following properties should hold at call time: Number is a free variable. (term_typing:var/1) String is a string (a list of character codes). (basic_props:string/1)
• The following properties hold upon exit: Number is a number. (basic_props:num/1)
• The following properties hold globally: basic_props:eval(number_codes(Number,String)) (basic_props:eval/1)

PREDICATE: number_codes/3:

number_codes(Number, String, Base)

String is the list of the ASCII codes of the characters comprising a representation of Number in base Base.

General properties:

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

Usage 1:

• Calls should, and exit will be compatible with: Base is a string (a list of character codes). (basic_props:string/1)
• The following properties should hold at call time: Number is a number. (basic_props:num/1) String is an integer. (basic_props:int/1)
• The following properties hold upon exit: Base is a string (a list of character codes). (basic_props:string/1)
• The following properties hold globally: basic_props:eval(number_codes(Number,String,Base)) (basic_props:eval/1)

Usage 2:

• The following properties should hold at call time: Number is a free variable. (term_typing:var/1) String is an integer. (basic_props:int/1) Base is a string (a list of character codes). (basic_props:string/1)
• The following properties hold upon exit: Number is a number. (basic_props:num/1)
• The following properties hold globally: basic_props:eval(number_codes(Number,String,Base)) (basic_props:eval/1)

PREDICATE: atom_number/2:

atom_number(Atom, Number)

Atom can be read as a representation of Number.

General properties:

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

Usage 1:

• Calls should, and exit will be compatible with: Number is a number. (basic_props:num/1)
• The following properties should hold at call time: Atom is an atom. (basic_props:atm/1)
• The following properties hold upon exit: Number is a number. (basic_props:num/1)
• The following properties hold globally: basic_props:eval(atom_number(Atom,Number)) (basic_props:eval/1)

Usage 2:

• The following properties should hold at call time: Atom is a free variable. (term_typing:var/1) Number is a number. (basic_props:num/1)
• The following properties hold upon exit: Atom is an atom. (basic_props:atm/1)
• The following properties hold globally: basic_props:eval(atom_number(Atom,Number)) (basic_props:eval/1)

PREDICATE: atom_length/2:

atom_length(Atom, Length) * ISO *

Length is the number of characters forming the name of Atom.

General properties:

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

Usage:

• Calls should, and exit will be compatible with: Length is an integer. (basic_props:int/1)
• The following properties should hold at call time: Atom is an atom. (basic_props:atm/1)
• The following properties hold upon exit: Length is an integer. (basic_props:int/1)
• The following properties hold globally: basic_props:eval(atom_length(Atom,Length)) (basic_props:eval/1)

PREDICATE: atom_concat/3:

atom_concat(Atom_1, Atom_2, Atom_12) * ISO *

Atom_12 is the result of concatenating Atom_1 followed by Atom_2.

General properties:

• The following properties hold globally: atom_concat(Atom_1,Atom_2,Atom_12) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

Usage 1:

• Description: Concatenate two atoms.
• Calls should, and exit will be compatible with: Atom_12 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties should hold at call time: Atom_1 is currently instantiated to an atom. (term_typing:atom/1) Atom_2 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold upon exit: Atom_12 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold globally: basic_props:eval(atom_concat(Atom_1,Atom_2,Atom_12)) (basic_props:eval/1)

Usage 2:

• Description: Non-deterministically split an atom.
• The following properties should hold at call time: Atom_1 is a free variable. (term_typing:var/1) Atom_2 is a free variable. (term_typing:var/1) Atom_12 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold upon exit: Atom_1 is currently instantiated to an atom. (term_typing:atom/1) Atom_2 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold globally: basic_props:eval(atom_concat(Atom_1,Atom_2,Atom_12)) (basic_props:eval/1)

Usage 3:

• Description: Take out of an atom a certain suffix (or fail if it cannot be done).
• The following properties should hold at call time: Atom_1 is a free variable. (term_typing:var/1) Atom_2 is currently instantiated to an atom. (term_typing:atom/1) Atom_12 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold upon exit: Atom_1 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold globally: basic_props:eval(atom_concat(Atom_1,Atom_2,Atom_12)) (basic_props:eval/1)

Usage 4:

• Description: Take out of an atom a certain prefix (or fail if it cannot be done).
• The following properties should hold at call time: Atom_1 is currently instantiated to an atom. (term_typing:atom/1) Atom_2 is a free variable. (term_typing:var/1) Atom_12 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold upon exit: Atom_2 is currently instantiated to an atom. (term_typing:atom/1)
• The following properties hold globally: basic_props:eval(atom_concat(Atom_1,Atom_2,Atom_12)) (basic_props:eval/1)

PREDICATE: sub_atom/4:

sub_atom(Atom, Before, Length, Sub_atom)

Sub_atom is formed with Length consecutive characters of Atom after the Before character. For example, the goal sub_atom(summer,1,4,umme) succeeds.

General properties:

• The following properties hold globally: sub_atom(Atom,Before,Length,Sub_atom) is side-effect free. (basic_props:sideff/2) This predicate is understood natively by CiaoPP. (basic_props:native/1)

Usage:

• Calls should, and exit will be compatible with: Sub_atom is an atom. (basic_props:atm/1)
• The following properties should hold at call time: Atom is an atom. (basic_props:atm/1) Before is an integer. (basic_props:int/1) Length is an integer. (basic_props:int/1)
• The following properties hold upon exit: Sub_atom is an atom. (basic_props:atm/1)
• The following properties hold globally: basic_props:eval(sub_atom(Atom,Before,Length,Sub_atom)) (basic_props:eval/1)

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