Information technology - Programming languages - Prolog - Part 1:
General Core
WORKING DRAFT TECHNICAL CORRIGENDUM 3

5.5.12 Options.

A processor may support one or more additional options, like stream options (7.10.2.11), stream close options (7.10.2.12), stream properties (7.10.2.13), read options (7.10.3), and write options (7.10.4) as an implementation specific feature.

@@@ The processing of options is associated only with instantiation errors and domain errors for the specific option domain. (Refer to 8.1.2 Notes)

7.1.6.3 Iterated-goal term

a) If T unifies with ^(_, G) then ...

a) If T has the form ^(_, G) then ...

7.8.3.4, Table 22

a1) If Term is a variable and there is an effective write-option variable_names(VN_list) and there is an element A = Term of the list VN_list with A an atom, then A is output with effective write-option quoted(false).

7.10.5 subclause a

e2) Else if Term has the form '{}'(Arg), and there is an effective write-option ignore_ops(false), then Term is output as a curly bracketed term (6.3.6), that is:

1) { (open curly char) is output

2) Arg is output by recursively applying these rules

3) } (close curly char) is output

h) If Term has a principal functor ...

h) If Term has a principal functor which is an
operator, and there is an effective write-option
ignore_ops(false), then the term is output in operator
form, that is:

1) The atom of the principal functor is output
in front of its argument (prefix operator), between
its arguments (infix operator), or after its argument
(postfix operator). In all cases, a space is output
to separate an operator from its argument(s) if any
ambiguity could otherwise arise.

Operators ',' and '|' are output as , (comma char) and | (bar char) respectively.

2) Each argument of the term is output by recursively
applying these rules. When an argument is itself
to be output in operator form, it is preceded by (
(open char) and followed by ) (close char) if: (i) the
principal functor is an operator whose priority is so
high that the term could not be re-input correctly with
same set of current operators, or (ii) the argument is
an atom which is a current operator.

1. Condition (ii) never applies, because there is a further contradicting condition in front: "When an argument is itself to be output in operator form". If we have an argument which is an atom then that atom is not be output in operator form. Only certain principal functors of arity one and two are to be output in operator form. Thus, we will never get to condition (ii).
2. The cases - (1) and - (1^a) are not mentioned explicitly.
3. The cases (1,2) and (1|2) are not mentioned.

2) Each argument of the term is output by recursively applying these rules. An argument is preceded by ( (open char) and followed by ) (close char) if: (i) the principal functor is an operator whose priority is so high that the term could not be re-input correctly with the same set of current operators, or (ii) the argument is an atom which is a current operator, or (iii) the principal functor is output as a prefix operator - and the argument is a non-negative number, or (iv) the principal functor is output as a prefix operator - and the argument is to be output in infix or postfix operator form.

7 When a built-in predicate has an argument whose type is a list of options (@@@ as input?), that argument will be an +xxx_options_list. (There should be a type name_options_list used in Template and Modes, and a corresponding domain_error(name_option)). That argument will always be associated with

1. an instantiation error, when the argument is a partial list, or an element is not a valid option but an instance of the element is a valid option.
2. a domain error, when an element is neither a valid option nor any instance is a valid option.

e) Constructs the clause with head H and body B,

b) the goal succeeds.

c) Options is a partial list or a list with an element
E which is a variable or which has a component
which is a variable, and an instantiated component is required.
— instantiation_error.

k) Parses C_Seq as a read-term (6.4) T.,

k) Parses C_Seq as a read-term (6.2.2) T.,

e) An element E of the Options list is neither a
variable nor a valid write-option
— domain_error(write_option, E).

write_term(1,[quoted(nonbool)]).
   domain_error(write_option,quoted(nonbool))
write_term(1,[quoted(B)]).
   domain_error(write_option,quoted(_))

B = true, write_term(1,[quoted(B)]).
   Succeeds, outputting the character 1.

Replace

write_canonical([1,2,3]).
   Succeeds, outputting the characters
.(1,.(2,.(3,[ ])))
    to the current output stream.

write_canonical([1,2,3]).
   Succeeds, outputting the characters
'.'(1,'.'(2,'.'(3,[])))
    to the current output stream.

Here are the values for X^Y for X, Y in -3..3.

e) VX and VY are integers and VX is not equal to 1 and VY is less than -1.
— type_error(float, VX).

e) VX and VY are integers and VY is negative and VX is greater than 1 or less than -1
— type_error(float, VX).

e) VX and VY are integers and VY is negative and VX is not equal to 1, 0, or -1
— type_error(float, VX).

2^(-1).
   evaluation_error(undefined).

2^(-1).
   type_error(float, 2).

Annex B
(informative)
Editorial notes

Unusual characters

All error subclauses (X.Y.Z.3) starting with C1: Mdash: —

C3 8.2.4.1: Theta: θ

C5 8.4.2: Ndash: –

C14 9.1.3:

Times: ×

Rightwards arrow: →

Union: ∪

Floor: ⌊ ⌋

Inequality: ≠

Logical and: ∧

Element of, not in: ∈, ∉

C15 9.3.11.1, 9.3.12.1, 9.3.13.1, C16:

Pi: π

Less or equal: ≤

Background

Document history