When each Calculation had its own text buffer, the Expression of an
overflowing output text was Undefined. Hence that Expression could have
been Undefined without the corresponding text being 'undef'. That situation
may not happen anymore since Calculation are stored in a shared buffer.
The most common case where only the approximate output is displayed
happens when the exact and the approximate outputs are equal, more
precisely when the exact output is equal to the approximate output with
the number of significant digits taken from user settings. That
clarification matters for the Poincare::Integers which have more digits than
the number of significant digits set by the user.
Besides, an Expression containing Units is simplified as
Multiplication(Float, Unit...) recorded identically into the exact and
the approximate outputs (except perhaps the number of significant
digits). Generally, the case where the number of digits in the output is
smaller or equal to the user setting would be matched by the condition,
stated above, that exact and approximate output are equal. But that
should also be the case whatever the number of significant digits. That
is why the presence of Units is matched specifically.
and 2 approximate outputs - one with the maximal number of significant
digits and one with the number of significant digits asked by the user.
This enables to find the approximate output without going through the
approximation routine again.
the app.
Fix wrong memoization: in calculation app input '[[1+i, 2][3,4]]', change
the complex format to Polar, go back to the calculation app --> the
calculation height was no recomputed despite the fact that the approximation
output changed.
When computing [[2,3,2][ln(2),1,5][1,8,9]] there was a memory pool
failure because of the computation of
exactAndApproximateDisplayedOutputsAreEqual. Because displaying the
right equal symbol is less important than displaying a result, we
encapsulate the method in an exception checkpoint: if there was not
enough memory on the pool to compute the equal sign, just return
EqualSign::Approximation.
