Adding the ability to use units with significant figures.

macros/contexts/contextExtensions.pl

@@ -392,18 +392,24 @@ package context::Extensions::Super;
 #
 sub super {
 	my ($self, $method, $context) = @_;
-	return $self->superClass($context)->can($method);
+	my $superclass = $self->superClass($context);
+	return unless $superclass;
+	return $superclass->can($method);
 }
 
 #
 #  Get the super class name from the extension hash in the context
 #
 sub superClass {
-	my $self  = shift;
-	my $class = ref($self) || $self;
-	my $name  = $self->extensionContext;
-	my $data  = (shift || $self->context)->{$name};
-	my $op    = $self->{bop} || $self->{uop};
+	my $self    = shift;
+	my $class   = ref($self) || $self;
+	my $name    = $self->extensionContext;
+	my $context = shift;
+	$context = $self->context unless defined $context;
+	return unless $context && ref($context);
+	my $data = $context->{$name};
+	return unless $data && ref($data) eq 'HASH';
+	my $op = $self->{bop} || $self->{uop};
 	return $op ? $data->{$op} : $data->{ substr($class, length($name) + 2) };
 }
 
@@ -460,6 +466,24 @@ sub extensionContext {
 	return $class;
 }
 
+#
+# Trap any calls to super-class methods that aren't in the overridden
+# class and pass them on to the original class.
+#
+sub AUTOLOAD {
+	our $AUTOLOAD;
+	my $self   = shift;
+	my $class  = $self->extensionContext;
+	my $method = (split(/::/, $AUTOLOAD))[-1];
+	if (substr($AUTOLOAD, 0, length($class) + 2) eq $class . '::') {
+		my $code = $self->super($method);
+		return &$code($self, @_) if $code;
+	}
+	my ($pkg, $file, $line, $subname) = caller(0);
+	die "Can't locate object method \"$method\" via package \"" . ref($self) . '"' . " at line $line of $file\n"
+		unless $method eq 'DESTROY';
+}
+
 #################################################################################################
 #################################################################################################
 

macros/contexts/contextSignificantFigures.pl

@@ -23,13 +23,13 @@ =head1 DESCRIPTION
 where the latter context, you or the student are not allowed to perform any operations on
 any numbers.
 
-This is primarily for decimal numbers and keep track of signficant figures.   With the context loaded,
+This is primarily for decimal numbers and keep track of significant figures.   With the context loaded,
 a call to C<Real> will parse the number or string to keep track of significant figures. For example,
 
     $x = Real('10.45');
     $y = Real('37.1834');
 
-and these numbers will have 6 and 4 signficant figures respectively.  To query the number of significant
+and these numbers will have 6 and 4 significant figures respectively.  To query the number of significant
 figures, use the C<sigfigs> method.  For example, C<< $x->sigfigs >> will return 4.
 
 The standard arithmetic operations +, -, *, / are defined for these and the result will have the correct
@@ -41,7 +41,7 @@ =head1 DESCRIPTION
 
    $x * $y;
 
-returns C<106.4> (with only 4 signficant figures, since one of them only has four).
+returns C<106.4> (with only 4 significant figures, since one of them only has four).
 
 Finally, we can also perform subtraction as in
 
@@ -52,24 +52,24 @@ =head1 DESCRIPTION
 
 =head2 Significant Figure Rules
 
-A reminder about signficant figures is that all non-zero digits are significant.  The rule about a zero's
-significance depends on where it is in a number.
+A reminder about significant figures is that all non-zero digits are significant.  The rule about a
+zero's significance depends on where it is in a number.
 
 =over
 
-=item * Zeros between any significant digits are signficant.  The zeros in 12.0034 are significant. There are 6
-significant figures in this number.
+=item * Zeros between any significant digits are significant.  The zeros in 12.0034 are significant.
+There are 6 significant figures in this number.
 
-=item * Zeros to the left of a non-zero digit are not significant.  The zeros in 0.00123 are not signficant.
-There are 3 significant figures in this number.
+=item * Zeros to the left of a non-zero digit are not significant.  The zeros in 0.00123 are 
+not significant.  There are 3 significant figures in this number.
 
-=item * Zeros to right of the decimal point and to the right a non-zero digit are significant.  The zeros in 12.3400 are
-significant. There are 6 significant figures in this number.
+=item * Zeros to right of the decimal point and to the right a non-zero digit are significant.
+The zeros in 12.3400 are significant. There are 6 significant figures in this number.
 
-=item * Zeros to the left of the decimal point and to the right of a non zero digit are not significant.  The
-zeros in 12300 are not significant. There are 3 significant figures in this number.  However, the presesence of
-a significant zero changes the rule.  The zeros in 12300.0  are all significant because the rightmost 0 is
-significant and therefore the other zeros are significant.
+=item * Zeros to the left of the decimal point and to the right of a non zero digit are not
+significant.  The zeros in 12300 are not significant. There are 3 significant figures in this number.
+However, the presence of a significant zero changes the rule.  The zeros in 12300.0  are all
+significant because the rightmost 0 is significant and therefore the other zeros are significant.
 
 
 =back
@@ -88,8 +88,8 @@ =head2 Significant Figure Rules
 
 =head3 Setting the number of significant figures.
 
-The number of significant figures can be set in two ways.  The first, in creation of the number if the option
-C<sigfigs> is used.  For example
+The number of significant figures can be set in two ways.  The first, in creation of the number if the 
+option C<sigfigs> is used.  For example
 
     Real('100', sigfigs => 2)
 
@@ -108,8 +108,8 @@ =head3 Setting the number of significant figures.
     $x = Real(17.05);
     $p = Real(4, sigfigs => 'inf') * $x;
 
-One can set the number of significant figures after a number has been created with the C<sigfigs> method.  For
-example,
+One can set the number of significant figures after a number has been created with the C<sigfigs> method.
+For example,
 
     $x = Real(12.3456);
 
@@ -118,9 +118,9 @@ =head3 Setting the number of significant figures.
 
 =head2 Flags
 
-There are two flags that give authors some control over messaging for near correct answers.  Recall that 
-a correct answer in this context is only given when a student has correct number of significant figures and 
-the correct answer (to all digits). 
+There are two flags that give authors some control over messaging for near correct answers.  Recall that
+a correct answer in this context is only given when a student has correct number of significant figures
+and the correct answer (to all digits).
 
 =over 
 
@@ -268,20 +268,20 @@ sub expFor {
 sub string {
 	my ($self, $equation, $precedence) = @_;
 	my $string = $self->format($self->{expForm} || $self->getFlag('alwaysExponentialForm') ? 'E' : 'f');
-	$string        =~ s/E(?:(-)|\+)0*(\d+)/x10^$1$2/;
+	$string        =~ s/E(?:(-)|\+)0*(\d+)/ 'x10^' . (defined($1) ? $1 : '') . $2 /e;
 	$string        =~ s/\^-(.*)/^(-$1)/;
 	return $string =~ m/x/ && $precedence ? "($string)" : $string;
 }
 
 sub TeX {
 	my ($self, $equation, $precedence) = @_;
 	my $tex = $self->format($self->{expForm} || $self->getFlag('alwaysExponentialForm') ? 'E' : 'f');
-	$tex =~ s/E(?:(-)|\+)0*(\d+)/\\times 10^{$1$2}/;
+	$tex =~ s/E([-+])0*(\d+)/'\\times 10^{' . ($1 eq '-' ? '-' : '') . $2 . '}'/e;
 	return $tex =~ m/\\times/ && $precedence ? "\\left($tex\\right)" : "{$tex}";
 }
 
 # Format the number in $value in either 'E' (exponential form) or 'f' decimal form using
-# $n signficant figures.
+# $n significant figures.
 
 # Example: format('E', '123.456', 6) returns 1.23456E+02
 # format('f', 1.23E-01, 3) returns '0.123'.
@@ -301,7 +301,7 @@ sub format {
 	return $value;
 }
 
-# Redefine addition.  The leftmost signifcant place in the result is needed to get the
+# Redefine addition.  The leftmost significant place in the result is needed to get the
 # correct value.
 
 sub add {
@@ -311,7 +311,7 @@ sub add {
 	return $self->new($value, sigfigs => main::max(0, $exp + $self->expFor($value, $exp)), computed => 1);
 }
 
-# Redefine subtraction.  The leftmost signifcant place in the result is needed to get the
+# Redefine subtraction.  The leftmost significant place in the result is needed to get the
 # correct value.
 
 sub sub {
@@ -337,7 +337,7 @@ sub div {
 	return $self->new($l->value / $r->value, sigfigs => main::min($l->{sigfigs}, $r->{sigfigs}), computed => 1);
 }
 
-# Redefine powers.  Record whether this is an integer power of 10 for use with exponetial form.
+# Redefine powers.  Record whether this is an integer power of 10 for use with exponential form.
 
 sub power {
 	my ($self, $l, $r, $other) = Value::checkOpOrderWithPromote(@_);
@@ -428,8 +428,6 @@ sub cmp_preprocess {
 # to the correct answer, but the incorrect number of significant figures.
 # If so, show a warning and given partial credit.
 
-# use Data::Dumper;
-
 sub cmp_postprocess {
 	my ($self, $ansHash) = @_;
 
@@ -444,8 +442,8 @@ sub cmp_postprocess {
 	# Create Value::Real versions of the student and correct answer
 	# and check if the numbers are within tolerance but the number of significant figures is not correct.
 
-	my $student_real = Value::Real->new($student->string);
-	my $correct_real = Value::Real->new($correct->string);
+	my $student_real = Value::Real->new($student->value);
+	my $correct_real = Value::Real->new($correct->value);
 
 	if ($self->getFlag('partial_incorrect_sf')
 		&& $student_real == $correct_real
@@ -572,7 +570,7 @@ sub checkExponentialForm {
 	}
 }
 
-# Copy the special properites used for exponential notation processing
+# Copy the special properties used for exponential notation processing
 
 sub COPY {
 	my ($self, $from, $to) = @_;
@@ -584,7 +582,7 @@ sub COPY {
 	return $to;
 }
 
-# Properly handle constants in exponential form, and add parenthese if needed
+# Properly handle constants in exponential form, and add parentheses if needed
 
 sub STRING {
 	my ($self, $fn, $precedence) = @_;
@@ -594,7 +592,7 @@ sub STRING {
 	return $string;
 }
 
-# Properly handle constants in exponential form, and add parenthese if needed
+# Properly handle constants in exponential form, and add parentheses if needed
 
 sub TEX {
 	my ($self, $fn, $precedence) = @_;
@@ -711,7 +709,7 @@ sub _eval {
 	return $self->COPY($self, $self->SUPER::_eval(@_)->with(hadPlus => 1));
 }
 
-# Override Parser::BOP::mulitoply to handle the formation of an exponential form
+# Override Parser::BOP::multiply to handle the formation of an exponential form
 
 package context::SignificantFigures::BOP::multiply;
 our @ISA = ('Parser::BOP::multiply', 'context::SignificantFigures::common');
@@ -765,7 +763,7 @@ sub _check {
 		#
 		$self->{def} = { %{ $self->{def} }, string => 'x', TeX => '\times' };
 		#
-		# Remove the variable from the expression if this was the only occurrance of 'x'.
+		# Remove the variable from the expression if this was the only occurrence of 'x'.
 		#
 		my $equation = $self->{equation};
 		$equation->{vCount}{x}--;
@@ -788,7 +786,7 @@ sub TeX {
 	return $self->TEX(sub { $self->SUPER::TeX }, @_);
 }
 
-# Override Parser::BOP::power to mark occurances of ten-to-a-power so we can
+# Override Parser::BOP::power to mark occurrences of ten-to-a-power so we can
 # recognize them when checking for exponential form
 
 package context::SignificantFigures::BOP::power;

t/contexts/significant_figures.t

@@ -28,6 +28,7 @@ sub expon  { context::SignificantFigures::Real->expFor($_[0], 0) }
 sub FORMAT { context::SignificantFigures::Real->format(@_) }
 
 subtest 'Test the helper functions.' => sub {
+
 	is ROUND(1.335,    3), '1.34',   'Round 1.335 to 3 sig figs.';
 	is ROUND(12.34567, 5), '12.346', 'Round 12.346 to 5 sig figs.';
 	is ROUND(1.005,    3), '1.01',   'Check that rounding up is working with non-perfect values';
@@ -53,6 +54,7 @@ subtest 'Test the helper functions.' => sub {
 };
 
 subtest 'Create numbers with significant digits using Real' => sub {
+
 	ok my $a1 = Real('0012.34'), 'Creating the number 0012.34';
 	is $a1->sigfigs, 4, '0012.34 has 4 significant figures.';
 	is $a1->E,       1, '0012.34 written as 1.234 * 10^1';
@@ -170,6 +172,7 @@ subtest 'Create numbers with significant digits using Real' => sub {
 };
 
 subtest 'Create numbers by specifying significant figures' => sub {
+
 	my $a1 = Real(2, sigfigs => 3);
 	is $a1->format('E'), '2.00E+00', '2 with 3 sig figs is 2.00';
 	is $a1->string,      '2.00',     'Correct string output.';
@@ -188,6 +191,7 @@ subtest 'Create numbers by specifying significant figures' => sub {
 };
 
 subtest 'Check for out of bounds significant figures' => sub {
+
 	my $a1 = Real('1');
 	like dies { Real('5', sigfigs => 20); }, qr/The number of significant figures must be less than 16/,
 		'Try to create a real with more than 16 sigfigs.';
@@ -206,6 +210,7 @@ subtest 'Check for out of bounds significant figures' => sub {
 };
 
 subtest 'Creating numbers with significant figures using Compute' => sub {
+
 	my $a1 = Compute('12.345');
 	is $a1->format('E'), '1.2345E+01', 'Ensure that the internal storage of 12.345 is correct.';
 	is $a1->string,      '12.345',     'Ensure that the string output of 12.345 is correct.';
@@ -369,7 +374,6 @@ subtest 'Subtracting two constants' => sub {
 	is $a11->format('E'), '1.02E+00', '1.03 - .005 = 1.02 (check format)';
 	is $a11->sigfigs,     3,          '1.03 - .005 = 1.02 (check sigfigs)';
 	is $a11->E,           0,          '1.03 - .005 = 1.02 (check exp)';
-
 };
 
 subtest 'Division' => sub {
@@ -386,15 +390,12 @@ subtest 'Division' => sub {
 };
 
 subtest 'Significant Figures for integers' => sub {
-	# my $a1 = Compute('1.0 * 10^2');
 	my $a1 = Compute('1.0E+02');
 	is $a1->format('E'), '1.0E+02', '1.0 * 10^2 internally is 1.0E+02';
 };
 
 subtest 'Significant Figures for partial credit' => sub {
-
 	# test an actual problem
-
 	my $source = <<~ 'END_SOURCE';
 		DOCUMENT();
 		loadMacros("PGstandard.pl","PGML.pl",'contextSignificantFigures.pl');
@@ -416,8 +417,6 @@ subtest 'Significant Figures for partial credit' => sub {
 		),
 		'source string renders';
 
-	# print Dumper $pg->{result};
-
 	is $pg->{result}{score}, 1, 'correct answer is scored correctly';
 
 	my $pg2 = WeBWorK::PG->new(

t/contexts/significant_figures_units.t

@@ -0,0 +1,46 @@
+#!/usr/bin/env perl
+
+=head1 SignificantFigure context
+
+Test the SignificantFigure context defined in contextSignificantFigure.pl.
+
+=cut
+
+use Test2::V0 '!E', { E => 'EXISTS' };
+
+die "PG_ROOT not found in environment.\n" unless $ENV{PG_ROOT};
+do "$ENV{PG_ROOT}/t/build_PG_envir.pl";
+
+use lib "$ENV{PG_ROOT}/lib";
+
+# load the Units module so that %Units::known_units is populated
+use Units;
+use Value;
+require Parser::Legacy;
+import Parser::Legacy;
+
+loadMacros('contextSignificantFigures.pl', 'contextUnits.pl');
+
+my $context = context::Units::extending("SignificantFigures")->withUnitsFor('length');
+
+subtest 'Setup a basic Unit context extending SignificantFigures' => sub {
+	Context($context);    # make it current without copying
+	ok(defined $context && ref($context), 'Got a context object');
+	is $context->{name}, 'Units-SignificantFigures', 'Context has correct name';
+};
+
+subtest 'Test a number with length units and significant figures' => sub {
+	Context($context);
+	ok my $a = Compute("123.0 cm"), 'able to compute with unit';
+
+	is $a, '123.0 cm', 'Value stringifies with units and sig figs';
+	ok $a == Compute('1.230 m'), 'Value stringifies with correct unit conversion and sig figs';
+	ok $a != Compute('123 cm'),  'Value does not lose significant figure information when stringified';
+
+	ok $a == Compute('4.035 ft'), 'Value in feet';
+	ok $a == Compute('4.034 ft'), 'Value in feet (a little off, but when converted to m is correct)';
+	ok $a == Compute('4.036 ft'), 'Value in feet (a little off, but when converted to m is correct)';
+
+};
+
+done_testing;