Christophe de Dinechin

The `-3` part seems to just disappear into thin air. This should be a syntax error.

Interval arithmetic

4

Add interval types to enable interval arithmetic.

Rounding flags

2

Add rounding flags for decimal computations, to be able to round up, down or towards/away from zero.

Rendering of HMS/DMS value in non-symbolic mode

1

When symbolic mode is switched off, bad rounding can cause surprising-looking results. Illustration: ``` rpl NumericResults 10.2555 FromHMS ToHMS ``` What shows up is `10:25:541.` [Original report][report] [report]: https://www.hpmuseum.org/forum/thread-20157-post-203660.html#pid203660

Combining `FromHMS` and `ToHMS` gives unrounded result

2

Running `10.3033 FromHMS ToHMS` gives the result `10.30.32.999629...` instead of the expected `10.30.33`. Here is the [original report][hpm] [hpm]: https://www.hpmuseum.org/forum/thread-20157-post-203609.html#pid203609

Converting HwFP to fraction gives truncated result

1

Running the following gives a totall wrong result: ``` rpl HFP 12 PREC 10.3033 FromHMS ToHMS ``` We expect `10.30.33`, instead we get `10:00:00` [Initial report][hpm] [hpm]: https://www.hpmuseum.org/forum/thread-20157-post-203627.html#pid203627

When integrating `'sin(x)/x'` between `0` and some other value, the expression is evaluating at `0`, which causes a `Divide by zero` error. On HP calculators, the problem does not exist....

Incorrect evaiuation of of `∂x(f(x+1))` and `∫x(f(x+1))`

2

With `f′` defined as `'∂x(f(x))'`, we end up with `x` on the stack above the expression. This is not true for just an expression.

Infinite loop simplifying one of the equations

1

One of the tests, `Simple Pendulum`, goes into an infinite loop, trying to simplify this: ``` rpl 'Σ(((2·x)!÷(2↑x·x!)²)²·sin((θmax_°)÷2)↑(2·x);((2·x)!÷(2↑x·x!)²)²·sin((θmax_°)÷2)↑(2·x);((2·x)!÷(2↑x·x!)²)²·sin((θmax_°)÷2)↑(2·x);((2·x)!÷(2↑x·x!)²)²·sin((θmax_°)÷2)↑(2·x))' ```

While saving for `Undo`, some peculiar crash, as if the stack had been reset above the `Undo` region. ``` doc/commands/comparisons.md:99:## > help/db50x.md:8234: Test #81: examples: On-line help examples help/db50x.md:8234: 81:067.001:...