☜	$ORDER 1990 Version of ANSI Standard					☞

2.2.7.11 $Order

$O[RDER] ( glvn )

See 2.2.2.2 for the definition of glvn.

This form returns a value which is a subscript according to a subscript ordering sequence. This ordering sequence is specified below with the aid of a function, CO, which is used for definitional purposes only, to establish the collating sequence.

CO(s,t) is defined, for strings s and t, as follows:

• When t follows s in the ordering sequence, CO(s,t) returns t.
• Otherwise, CO(s,t) returns s.

Let m and n be strings satisfying the definition of numeric data values (see 2.2.3.1), and u and v be nonempty strings which do not satisfy this definition. The following cases define the ordering sequence:

1. CO("",s) = s.
2. CO(m,n) = n if n > m; otherwise, CO(m,n) = m.
3. CO(m,u) = u.
4. CO(u,v) = v if v ] u; otherwise, CO(u,v) = u.

In words, all strings follow the empty string, numerics collate in numeric order, numerics precede nonnumeric strings, and nonnumeric strings are ordered by the conventional ASCII collating sequence.

Only subscripted forms of lvn and gvn are permitted. Let lvn or gvn be of the form Name(s₁, s₂, ..., s_n) where s_n may be the empty string. Let A be the set of subscripts that follow s_n. That is, for all s in A:

1. CO(s_n,s) = s and
2. $D(Name(s₁, s₂, ..., s_n–1, s)) is not zero.

Then $O(Name(s₁, s₂, ..., s_n)) returns that value t in A such that CO(t,s) = s for all s not equal to t; that is, all other subscripts which follow s_n also follow t.

If no such t exists, $O returns the empty string.

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Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

This page most recently updated on 15-Nov-2023, 13:10:43.

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