/ modules / paradigms / Textual_Constant.py 

 SYNOPSIS

     Textual_Constant (table, idColumn, cardinality, phraseList,
         mapping=TextUtils.mappings.uppercaseAlphanumericOthersToWhitespace,
         deleteList=TextUtils.deleteLists.keepAll)

         table
             A table to query, e.g., "holding".

         idColumn
             The table's object identifier column (i.e., the column
             to be selected), e.g., "holding_id".

         cardinality
             A Cardinality object representing the cardinality of
             'table'.  Should be Cardinality("1") or
             Cardinality("1?").

         phraseList
             A list of zero or more phrases, e.g.,
             ["I am Sam", "Sam am I", "Green Eggs and Ham"].

         mapping
             A Python character mapping table (i.e., a string of
             length 256, indexed by ASCII character code) to process
             'phraseList' and constraint text with.  Defaults to
             'uppercaseAlphanumericOthersToWhitespace', which maps
             alphanumeric characters to their uppercase equivalents
             and all other characters to whitespace (i.e., to word
             separators).

         deleteList
             A string of zero or more characters to delete from
             'phraseList' and constraint text.  The default is the
             empty string, which keeps all characters.

 DESCRIPTION

     Translates a textual constraint to a constant TRUE or FALSE
     depending on whether the constraint text matches a body of
     constant text.

     This paradigm parses both constraint text and the phrases in
     'phraseList' into word sequences by: 1) deleting any characters
     that appear in 'deleteList'; 2) mapping the remaining characters
     using 'mapping'; and 3) treating sequences of whitespace
     characters as word separators.  Comparison of words is then
     based on straight string equality.

     A constraint that matches 'phraseList' results in the query

         SELECT idColumn FROM table
             WHERE 1 = 1

     being returned.  Otherwise, the query

         SELECT idColumn FROM table
             WHERE 1 = 0

     is returned.

     Exceptions thrown:

         no query words specified

 AUTHOR

     Greg Janee
     gjanee@alexandria.ucsb.edu

 HISTORY

     $Log: Textual_Constant.py,v $
     Revision 1.2  2003/04/16 18:32:11  valentin
     updated to latest translator code

     Revision 1.1  2002/11/04 22:46:14  gjanee
     Initial revision