left_x, right_x, y_coords, terminal-size
Plot an array of horizontal error bars.

EXAMPLES
--------

1. Plot constant, symmetric error bars.

   0>float x_coords(100)
   0>float y_coords(100)
   0>float sigma
   ...
   0>pgerrx x_coords - sigma, x_coords + sigma, y_coords

2. Plot varying, symmetric error bars.

   0>float x_coords(100)
   0>float y_coords(100)
   0>float error_bars(100)
   ...
   0>pgerrx x_coords - error_bars, x_coords + error_bars, y_coords

3. Plot varying asymmetric error bars.

   0>float y_coords(100)
   0>float left_bars(100)
   0>float right_bars(100)
   ...
   0>pgerrx left_bars, right_bars, y_coords

PARAMETERS
----------
left_x        -    The X-axis world-coordinates of the left end
                   of each error bar.

right_x       -    The X-axis world-coordinates of the right end
                   of each error bar.

y_coords      -    The Y-axis coordinates of each error bar.

terminal-size -    (Optional: default=1)
                   The height of the error-bar terminals relative to
                   their default height.

Note that if the three coordinate arrays contain differing numbers of
elements, the smallest array will dictate the number of error bars
drawn.