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Revision 3716 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Sun Oct 16 03:37:17 2005 UTC (14 years, 1 month ago) by dpvc
File length: 1999 byte(s)
Diff to previous 3370
In the past, when Value objects were inserted into strings, they would
automatically include parentheses so that if you had $f equal to 1+x
and $g equal to 1-x, then Formula("$f/$g") would mean (1+x)/(1-x)
rather than 1+(x/1)-x, which is what would happen as a straing string
substitution.

The problem is that this would also happen for real numbers, vectors,
and everything else, even when it wasn't necessary.  So if $x=Real(3),
then "Let x = $x" would be "Let x = (3)".

I have changed the behavior of the string concatenation for Value
objects so that parentheses are only added in a few cases: for
Formulas, Complex numbers, and Unions.  This makes the other Value
objects work more like regular variables in strings, but might cause
some problems with strings that are used as formulas.  For example, if
$a = Real(-3), then "x + 2 $a" will become "x + 2 -3", or "x-1" rather
than the expected "x - 6".  (The old approach would have made it "x +
2 (-3)" which would have worked properly).  For the most part, it is
easier to use something like "x + 2*$a" or even "x" + 2*$a in this
case, so the extra trouble of having to avoid parentheses when you
really meant to substitute the value into a string didn't seem worth
it.

Revision 3370 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Tue Jul 12 22:29:53 2005 UTC (14 years, 5 months ago) by dpvc
File length: 1991 byte(s)
Diff to previous 3192
A first pass at making parser error messages localizable.  The
Context()->{error}{msg} hash can be used to specify translations of
the standard messages.  For example,

    Context()->{error}{msg}{'Division by zero'} = "Don't divide by zero, dude!";
    Context()->{error}{msg}{'Function '%s' has too many inputs'} =
        "You passed too many arguments to '%s'";

(I didn't translate into another language, here, but you could do
that, too.)

The msg hash could also be used within answer checkers to make certain
answer messages more appropriate for the given type of expected answer.

Revision 3192 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Wed Mar 16 13:30:28 2005 UTC (14 years, 8 months ago) by dpvc
File length: 1988 byte(s)
Diff to previous 2800
Update the overloaded operators so that they can be overridden by
subclasses of the predefined object classes.  This involves calling
the objects method rather than using a hard reference to the routine
in the parent class.

Also, change the name of the string comparison routine to
compare_string to avoid conflicts with cmp that is used to produce the
answer checker for the class.

Finally, in Value.pm, promotePrecedence no longer has to do fancy
footwork to get "special" precedence to work (this was a hack to get
around the misfeature of the overloaded operators -- now that that is
being handled correctly, there is no need for it).

Revision 2800 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Sun Sep 19 14:27:39 2004 UTC (15 years, 2 months ago) by dpvc
File length: 1923 byte(s)
Diff to previous 2660
Added isZero and isOne checks for Parser::Value objects (i.e., for
constants within formulas).  These now correctly handle vector and
matrices, in particular.  The isOne and isZero checks are used in the
reduce() method to simplify formulas.

Revision 2660 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Fri Aug 20 15:52:32 2004 UTC (15 years, 3 months ago) by dpvc
File length: 1892 byte(s)
Diff to previous 2625
A number of adjustments to get negative infinities to work better.
They used to be stored as separate Parser strings, but now they are
flagged versions of a single string.

All of the problems are really due to the fact that there is no
Infinity class in the Parser (only a Value version).  That should be
changed, but will require some work, and can be put off for now.

It would be best if the classes within the two packages would match up
nearly 1-to-1, but for historical reasons, they don't.  Since the
introduction of Real, String and Infinity classes to the Value
package, The Infinity class is the one main difference between the
two, and once that is fixed, everything needs to be looked over to
check for unnecessary complications due to the historical lack of classes
in one or the other package.

Revision 2625 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Mon Aug 16 18:35:12 2004 UTC (15 years, 3 months ago) by dpvc
File length: 1927 byte(s)
Diff to previous 2609
Added string comparison to all Value object classes (to compare the
string value of an object to another string).

Overloaded perl '.' operator to do dot product when the operands are
formulas returning vectors.  (Part of the auto-generation of
formulas).

A few improvements to real and complex class output results.

Made Union class slightly more robust and removed need for makeUnion
method other than in the Union itself.

Revision 2609 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Sat Aug 14 13:54:52 2004 UTC (15 years, 4 months ago) by dpvc
File length: 1924 byte(s)
Diff to previous 2606
Added a String type to the Value package.  Mostly this is to make it
possible to generate an answer checker for it that uses the parser.
It also makes it more consistent for handling things like stringify,
especially when they are recursively called internally.

Added new default strings "NONE" and "DNE", since these get used a
lot.

Modified how the default parameters are set up for the answer
checkers, and how the answer checker reports the expected answer type
in type mismatch error messages.

Revision 2606 - (view) (download) (as text) (annotate) - [select for diffs]
Modified Sat Aug 14 11:25:47 2004 UTC (15 years, 4 months ago) by dpvc
File length: 2058 byte(s)
Diff to previous 2603
Can now specify that the objects stringify themselfs in their TeX
forms rather than their answer-string forms.  This makes it easier to
use the objects in the text of a problem (without having to call ->TeX
explicitly each reference).

Use

       Context()->texStrings

to start outputting TeX strings, and

      Context()->normalStrings

to switch back.

Revision 2603 - (view) (download) (as text) (annotate) - [select for diffs]
Added Fri Aug 13 23:01:07 2004 UTC (15 years, 4 months ago) by dpvc
File length: 2081 byte(s)
Added an Infinite object class for the Value package.  Still need to
add it to the Parser package.

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