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Diff for /loncom/interface/entities.pm between versions 1.17 and 1.18

version 1.17, 2008/11/20 13:07:32 version 1.18, 2008/11/21 20:17:11
Line 26 Line 26
 #  #
 #  #
   
 =pod  
   
 =head1 NAME  
   
 Apache::entities.pm  
   
 =head1 SYNOPSIS  
   
 This file contains a table driven entity-->latex converter.  
   
 This is part of the LearningOnline Network with CAPA project  
 described at http://www.lon-capa.org.  
   
 =head1 OVERVIEW  
   
   
 Assumptions:  
  The number of entities in a resource is small compared with the  
  number of possible entities that might be translated.  
  Therefore the strategy is to match a general entity pattern  
  &.+; over and over, pull out the match look it up in an entity -> tex hash  
  and do the replacement.  
   
 In order to simplify the hash, the following reductions are done:  
  &#d+; have the &# and ; stripped and is converted to an int.  
  &#.+; have the &#x and ; stripped and is converted to an int as a hex  
                            value.  
  All others have the & and ; stripped.  
   
   
 The hash:  Add new conversions here; leave off the leading & and the trailing ;  
 all numeric entities need only appear as their decimal versions  
 (e.g. no need for 1234 is sufficient, no need for 0x4d2 as well.  
   
 This entity table is mercilessly cribbed from the  HTML pocket reference  
 table starting at pg 82.  In most cases the LaTeX equivalent codes come from  
 the original massive regular expression replacements originally by   
 A. Sakharuk in lonprintout.pm  
   
 I also want to acknowledge  
  ISO Character entities and their LaTeX equivalents by   
     Vidar Bronken Gundersen, and Rune Mathisen  
   http://www.bitjungle.com/isoent-ref.pdf  
   
   
 Note numerical entities are essentially unicode character codes.  
   
   
 =head1 SUBROUTINES  
   
 =over  
   
 =item entity_to_utf8()  
   
   
 Convert a numerical entity (that does not exist in our hash)  
  to its UTF-8 equivalent representation.  
  This allows us to support, to some extent, any entity for which  
  dvipdf can find a gylph (given that LaTeX is now UTF-8 clean).  
   
 Parameters:  
   unicode  - The unicode for the character.  This is assumed to  
              be a decimal value  
 Returns:  
   The UTF-8 equiavalent of the value.  
   
 =item entity_to_latex()  
   
  Convert an entity to the corresponding LateX if possible.  
  If not possible, and the entity is numeric,  
  the entity is treated like a Unicode character and converted  
  to UTF-8 which should display as long as dvipdf can find the  
  appropriate glyph.  
   
  The entity is assumed to have already had the   
  &;  or & ; removed  
   
 Parameters:  
   entity    - Name of entity to convert.  
 Returns:  
  One of the following:  
   - Latex string that produces the entity.  
   - UTF-8 equivalent of a numeric entity for which we don't have a latex string.  
   - ' ' for text entities for which there's no latex equivalent.  
   
   
 =item replace_entities()  
   
  Convert all the entities in a string.  
  We locate all the entities, pass them into entity_to_latex and   
  and replace occurences in the input string.  
  The assumption is that there are few entities in any string/document  
  so this looping is not too bad.  The advantage of looping vs. regexping is  
  that we now can use lookup tables for the translation in entity_to_latex above.  
   
 Parameters:  
   input   - Input string/document  
 Returns  
   input with entities replaced by latexable stuff (UTF-8 encodings or  
   latex control strings to produce the entity.  
   
 =back  
   
 =cut  
   
 package Apache::entities;  package Apache::entities;
 use strict;  use strict;
   
Line 1164  sub replace_entities { Line 1059  sub replace_entities {
 1;   1; 
   
 __END__  __END__
   
   =pod
   
   =head1 NAME
   
   Apache::entities.pm
   
   =head1 SYNOPSIS
   
   This file contains a table driven entity-->latex converter.
   
   This is part of the LearningOnline Network with CAPA project
   described at http://www.lon-capa.org.
   
   =head1 OVERVIEW
   
   
   Assumptions:
    The number of entities in a resource is small compared with the
    number of possible entities that might be translated.
    Therefore the strategy is to match a general entity pattern
    &.+; over and over, pull out the match look it up in an entity -> tex hash
    and do the replacement.
   
   In order to simplify the hash, the following reductions are done:
    &#d+; have the &# and ; stripped and is converted to an int.
    &#.+; have the &#x and ; stripped and is converted to an int as a hex
                              value.
    All others have the & and ; stripped.
   
   
   The hash:  Add new conversions here; leave off the leading & and the trailing ;
   all numeric entities need only appear as their decimal versions
   (e.g. no need for 1234 is sufficient, no need for 0x4d2 as well.
   
   This entity table is mercilessly cribbed from the  HTML pocket reference
   table starting at pg 82.  In most cases the LaTeX equivalent codes come from
   the original massive regular expression replacements originally by 
   A. Sakharuk in lonprintout.pm
   
   I also want to acknowledge
    ISO Character entities and their LaTeX equivalents by 
       Vidar Bronken Gundersen, and Rune Mathisen
     http://www.bitjungle.com/isoent-ref.pdf
   
   
   Note numerical entities are essentially unicode character codes.
   
   
   =head1 SUBROUTINES
   
   =over
   
   =item entity_to_utf8()
   
   
   Convert a numerical entity (that does not exist in our hash)
    to its UTF-8 equivalent representation.
    This allows us to support, to some extent, any entity for which
    dvipdf can find a gylph (given that LaTeX is now UTF-8 clean).
   
   Parameters:
     unicode  - The unicode for the character.  This is assumed to
                be a decimal value
   Returns:
     The UTF-8 equiavalent of the value.
   
   =item entity_to_latex()
   
    Convert an entity to the corresponding LateX if possible.
    If not possible, and the entity is numeric,
    the entity is treated like a Unicode character and converted
    to UTF-8 which should display as long as dvipdf can find the
    appropriate glyph.
   
    The entity is assumed to have already had the 
    &;  or & ; removed
   
   Parameters:
     entity    - Name of entity to convert.
   Returns:
    One of the following:
     - Latex string that produces the entity.
     - UTF-8 equivalent of a numeric entity for which we don't have a latex string.
     - ' ' for text entities for which there's no latex equivalent.
   
   
   =item replace_entities()
   
    Convert all the entities in a string.
    We locate all the entities, pass them into entity_to_latex and 
    and replace occurences in the input string.
    The assumption is that there are few entities in any string/document
    so this looping is not too bad.  The advantage of looping vs. regexping is
    that we now can use lookup tables for the translation in entity_to_latex above.
   
   Parameters:
     input   - Input string/document
   Returns
     input with entities replaced by latexable stuff (UTF-8 encodings or
     latex control strings to produce the entity.
   
   =back
   
   =cut
Removed from v.1.17  
changed lines
  Added in v.1.18

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