View of /branches/rel-2-4-patches/pg/doc/MathObjects/extensions/7-context.pg

    1 ##########################################################
    2 #
    3 #  Example showing how to switch different contexts
    4 #
    5 
    6 DOCUMENT();        # This should be the first executable line in the problem.
    7 
    8 loadMacros(
    9   "PGbasicmacros.pl",
   10   "PGanswermacros.pl",
   11   "Parser.pl",
   12   "parserTables.pl",
   13 );
   14 
   15 TEXT(beginproblem());
   16 
   17 BEGIN_TEXT
   18 $BEGIN_ONE_COLUMN
   19 
   20 In this problem, we compare formulas in complex and vector contexts.
   21 Note the difference between how ${BTT}i${ETT} is treated in the two
   22 contexts.  Note that 'Number' comprises both real and complex numbers.
   23 $PAR
   24 
   25 Assuming that ${BTT}${DOLLAR}x = Formula('x')${ETT}, it can be used as follows:
   26 $PAR
   27 
   28 END_TEXT
   29 
   30 $x = Formula('x');
   31 
   32 ##########################################################
   33 #
   34 #  Use Complex context
   35 #
   36 
   37 Context('Complex');
   38 
   39 BEGIN_TEXT
   40 \{Title("The Complex context:")\}
   41 $PAR
   42 \{ParserTable(
   43    'i',
   44    'Formula("1+3i")',
   45    'Formula("x+3i")',
   46    '1 + 3*i',
   47    '$x + 3*i',
   48    '$z = tan(2*i)',
   49    'Formula("sinh(zi)")',
   50    'Formula("3i+4j-k")',
   51    'Formula("3i+4j-k")->eval',
   52    '3*i + 4*j - k',
   53 )\}
   54 $PAR$BR
   55 END_TEXT
   56 
   57 
   58 ##########################################################
   59 #
   60 #  Use Vector context
   61 #
   62 
   63 Context('Vector');
   64 
   65 BEGIN_TEXT
   66 \{Title("The Vector context:")\}
   67 $PAR
   68 \{ParserTable(
   69    'i',
   70    'Formula("1+3i")',
   71    'Formula("x+3i")',
   72    '1 + 3*i',
   73    '$x + 3*i',
   74    '$z = tan(2*i)',
   75    'Formula("sinh(zi)")',
   76    'Formula("3i+4j-k")',
   77    'Formula("3i+4j-k")->eval',
   78    '3*i + 4*j - k',
   79 )\}
   80 
   81 $END_ONE_COLUMN
   82 END_TEXT
   83 
   84 ###########################################################
   85 
   86 ENDDOCUMENT();        # This should be the last executable line in the problem.