[WWcvs] pg: Fix LimitedPolynomial-Strict to check for singlePowers (there was a typo) and to consider constants to be coefficients of

[dpvc v. a. <we...@ma...>]

Log Message:
-----------
Fix LimitedPolynomial-Strict to check for singlePowers (there was a
typo) and to consider constants to be coefficients of x^0.

Give better error messages in some cases.

Modified Files:
--------------
    pg/macros:
        contextLimitedPolynomial.pl

Revision Data
-------------
Index: contextLimitedPolynomial.pl
===================================================================
RCS file: /webwork/cvs/system/pg/macros/contextLimitedPolynomial.pl,v
retrieving revision 1.17
retrieving revision 1.18
diff -Lmacros/contextLimitedPolynomial.pl -Lmacros/contextLimitedPolynomial.pl -u -r1.17 -r1.18
--- macros/contextLimitedPolynomial.pl
+++ macros/contextLimitedPolynomial.pl
@@ -139,6 +139,7 @@
 
 #
 #  Mark a variable as having power 1
+#  Mark a number as being present (when strict coefficients are used)
 #  Mark a monomial as having its given powers
 #
 sub markPowers {
@@ -148,6 +149,8 @@
     $self->{index} = $vIndex->{$self->{name}};
     $self->{exponents} = [(0) x scalar(keys %{$vIndex})];
     $self->{exponents}[$self->{index}] = 1;
+  } elsif ($self->class eq 'Number') {
+    $self->{exponents} = [] if $self->context->flag("strictCoefficients");
   }
   if ($self->{exponents}) {
     my $power = join(',',@{$self->{exponents}});
@@ -199,11 +202,6 @@
   $self->checkPowers;
 }
 
-sub checkStrict {
-  my $self = shift;
-  $self->Error("You can only use addition for the terms of a polynomial",$self->{bop});
-}
-
 ##############################################
 
 package LimitedPolynomial::BOP::subtract;
@@ -216,11 +214,6 @@
   $self->checkPowers;
 }
 
-sub checkStrict {
-  my $self = shift;
-  $self->Error("You can only use subtraction between the terms of a polynomial",$self->{bop});
-}
-
 ##############################################
 
 package LimitedPolynomial::BOP::multiply;
@@ -263,7 +256,7 @@
 
 sub checkStrict {
   my $self = shift;
-  $self->Error("You can only use '%s' to form fractions",$self->{bop}) if $self->{lop}->class eq 'BOP';
+  $self->Error("You can only use '%s' to form numeric fractions",$self->{bop}) if $self->{lop}->class eq 'BOP';
 }
 
 ##############################################
@@ -431,7 +424,7 @@
   #  A context where coefficients can't include operations
   #
   $context = $main::context{"LimitedPolynomial-Strict"} = $context->copy;
-  $context->flags->set(strictCoefficients=>1, singelPowers=>1, reduceConstants=>0);
+  $context->flags->set(strictCoefficients=>1, singlePowers=>1, reduceConstants=>0);
   $context->functions->disable("All");  # can be re-enabled if needed
 
   main::Context("LimitedPolynomial");  ### FIXME:  probably should require author to set this explicitly