This package was developed as part of the GRASP
project, where it is used for browsing lexical and ontology information,
which is normally stored using‘dictionary’order, rather than
the more conventional alphabetical ordering based on character codes. To
achieve programmable ordering, the table package defines‘order
tables’. An order table is a table with the cardinality of the
size of the character set (256 for extended ASCII),
and maps each character onto its‘order number’, and some
characters onto special codes.
The default (exact) table matches all character codes
onto themselves. The default case_insensitive table matches
all uppercase characters onto their corresponding lowercase character.
The tables iso_latin_1 and iso_latin_1_case_insensitive
map the ISO-latin-1 letters with diacritics into their plain
counterpart.
To support dictionary ordering, the following special categories are
defined:
| ignore | Characters of the ignore set are simple discarded
from the input. |
| break | Characters from the break set are treated as
word-breaks, and each non-empty sequence of them is considered equal. A
word break precedes a normal character. |
| tag | Characters of type tag indicate the start of a‘tag’that
should not be considered in ordering, unless both strings are the same
upto the tag. |
The following predicates are defined to manage and use these tables:
- new_order_table(+Name,
+Options)
- Create a new, or replace the order-table with the given name (an atom). Options
is a list of options:
case_insensitive | Map all upper- to
lowercase characters. |
iso_latin_1 | Start with an ISO-Latin-1 table |
iso_latin_1_case_insensitive | Start with a
case-insensitive ISO-Latin-1 table |
copy(+Table) | Copy all entries
from Table. |
tag(+ListOfCodes) | Add these
characters to the set of‘tag’characters. |
ignore(+ListOfCodes) | Add these
characters to the set of‘ignore’characters. |
break(+ListOfCodes) | Add these
characters to the set of‘break’characters. |
+Code1 = +Code2 | Map Code1
onto Code2. |
- order_table_mapping(+Table,
?From, ?To)
- Read the current mapping. To is a character code or one of
the atoms
break, ignore or tag.
- compare_strings(+Table,
+S1, +S2, -Result)
- Compare two strings using the named Table. S1 and
S2 may be atoms, strings or code-lists. Result is
one of the atoms
<, = or >.
- prefix_string(+Table,
+Prefix, +String)
- Succeeds if Prefix is a prefix of String using the
named
Table.
- prefix_string(+Table,
+Prefix, -Rest, +String)
- Succeeds if Prefix is a prefix of String using the
named
Table, and Rest is unified with the remainder of
String that is not matched. Please note that the existence of
an order-table implies simple contatenation using atom_concat/3
cannot be used to determine the non-matched part of the string.
- sub_string(+Table,
+Sub, +String)
- Succeeds if
Sub is a substring of String using the named
Table.
