Basic predicates handling names of constants

Version: 1.5#118 (2000/4/19, 18:13:43 CEST)

The Ciao system provides builtin predicates which allow dealing with names of constants (atoms or numbers). As an atom name must be of less than 512 characters, to handle sequences of more characters, strings (character code lists) must be used.

• 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.

Usage 2: name(-(constant),+string)

• Description: If String can be interpreted as a number, Const is unified with that number, otherwise with the atom whose name is String.

Usage 3:

• 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)

Usage 4:

• 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)

PREDICATE: atom_codes/2:

atom_codes(Atom,String)

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

Usage 3: * ISO *

• 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)

Usage 4: * ISO *

• 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)

PREDICATE: number_codes/2:

number_codes(Number,String)

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

Usage 3: * ISO *

• 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)

Usage 4: * ISO *

• 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)

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.

Usage 3:

• 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) Base is an integer. (basic_props:int/1)
• The following properties hold upon exit: String is a string (a list of character codes). (basic_props:string/1)

Usage 4:

• 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) Base is an integer. (basic_props:int/1)
• The following properties hold upon exit: Number is a number. (basic_props:num/1)

PREDICATE: atom_length/2:

atom_length(Atom,Length)

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

Usage 2: * ISO *

• 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)

PREDICATE: atom_concat/3:

atom_concat(Atom_1,Atom_2,Atom_12)

Atom_12 is the result of concatenating Atom_1 followed by Atom_2.

Usage 1: atom_concat(+atom,+atom,?(atom)) * ISO *

• Description: Concatenate two atoms.

Usage 2: atom_concat(-(atom),-(atom),+atom) * ISO *

• Description: Non-deterministically split an atom.

Usage 3: atom_concat(-(atom),+atom,+atom) * ISO *

• Description: Take out of an atom a certain suffix (or fail if it cannot be done).

Usage 4: atom_concat(+atom,-(atom),+atom) * ISO *

• Description: Take out of an atom a certain prefix (or fail if it cannot be done).

Usage 5: * ISO *

• 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)

Usage 6: * ISO *

• 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)

Usage 7: * ISO *

• 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)

Usage 8: * ISO *

• 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)

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.

Usage 2:

• 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 currently instantiated to an integer. (term_typing:integer/1) Length is currently instantiated to an integer. (term_typing:integer/1)
• The following properties hold upon exit: Sub_atom is an atom. (basic_props:atm/1)

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