Fix a bug in which a negative decimal input would not be displayed with
the correct width in the output. Before this commit, the output was
incorrectly
$ seq -w -.1 .1 .11
-0.1
0.0
0.1
After this commit, the output is correctly
$ seq -w -.1 .1 .11
-0.1
00.0
00.1
The code was failing to take into account that the input decimal "-.1"
needs to be displayed with a leading zero, like "-0.1".
Pad infinity and negative infinity values with spaces when using the
`-w` option to `seq`. This corrects the behavior of `seq` to match that
of the GNU version:
$ seq -w 1.000 inf inf | head -n 4
1.000
inf
inf
inf
Previously, it incorrectly padded with 0s instead of spaces.
* seq: use BigDecimal to represent floats
Use `BigDecimal` to represent arbitrary precision floats in order to
prevent numerical precision issues when iterating over a sequence of
numbers. This commit makes several changes at once to accomplish this
goal.
First, it creates a new struct, `PreciseNumber`, that is responsible for
storing not only the number itself but also the number of digits (both
integer and decimal) needed to display it. This information is collected
at the time of parsing the number, which lives in the new
`numberparse.rs` module.
Second, it uses the `BigDecimal` struct to store arbitrary precision
floating point numbers instead of the previous `f64` primitive
type. This protects against issues of numerical precision when
repeatedly accumulating a very small increment.
Third, since neither the `BigDecimal` nor `BigInt` types have a
representation of infinity, minus infinity, minus zero, or NaN, we add
the `ExtendedBigDecimal` and `ExtendedBigInt` enumerations which extend
the basic types with these concepts.
* fixup! seq: use BigDecimal to represent floats
* fixup! seq: use BigDecimal to represent floats
* fixup! seq: use BigDecimal to represent floats
* fixup! seq: use BigDecimal to represent floats
* fixup! seq: use BigDecimal to represent floats
