##########################################################
#
#  Example showing how to switch different contexts
#

DOCUMENT();        # This should be the first executable line in the problem.

loadMacros(
  "PGbasicmacros.pl",
  "PGanswermacros.pl",
  "Parser.pl",
  "parserTables.pl",
);

TEXT(beginproblem());

BEGIN_TEXT
$BEGIN_ONE_COLUMN

In this problem, we compare formulas in complex and vector contexts.
Note the difference between how ${BTT}i${ETT} is treated in the two
contexts.  Note that 'Number' comprises both real and complex numbers.
$PAR

Assuming that ${BTT}${DOLLAR}x = Formula('x')${ETT}, it can be used as follows:
$PAR

END_TEXT

$x = Formula('x');

##########################################################
#
#  Use Complex context
#

Context('Complex');

BEGIN_TEXT
\{Title("The Complex context:")\}
$PAR
\{ParserTable(
   'i',
   'Formula("1+3i")',
   'Formula("x+3i")',
   '1 + 3*i',
   '$x + 3*i',
   '$z = tan(2*i)',
   'Formula("sinh(zi)")',
   'Formula("3i+4j-k")',
   'Formula("3i+4j-k")->eval',
   '3*i + 4*j - k',
)\}
$PAR$BR
END_TEXT


##########################################################
#
#  Use Vector context
#

Context('Vector');

BEGIN_TEXT
\{Title("The Vector context:")\}
$PAR
\{ParserTable(
   'i',
   'Formula("1+3i")',
   'Formula("x+3i")',
   '1 + 3*i',
   '$x + 3*i',
   '$z = tan(2*i)',
   'Formula("sinh(zi)")',
   'Formula("3i+4j-k")',
   'Formula("3i+4j-k")->eval',
   '3*i + 4*j - k',
)\}

$END_ONE_COLUMN
END_TEXT

###########################################################

ENDDOCUMENT();        # This should be the last executable line in the problem.