Re: [lmi] UI for entering amounts in bp (was: master 7b0b9c3: Make 'InputFundManagementFee' a pure number (not bp))

[Vadim Zeitlin]

On Tue, 5 Jun 2018 18:42:55 +0000 Greg Chicares <address@hidden> wrote:

GC> On 2018-06-05 16:56, Vadim Zeitlin wrote:
GC> > On Tue,  5 Jun 2018 12:49:08 -0400 (EDT) Greg Chicares <address@hidden> 
wrote:
GC> [...]
GC> > GC>     Make 'InputFundManagementFee' a pure number (not bp)
GC> > GC>     
GC> > GC>     Redefined this input field to mean a pure number, not a number of 
basis
GC> > GC>     points. Now all GUI input fields are consistently pure numbers.
GC> > 
GC> >  Wouldn't it be nice to allow entering the number in the UI in bp or,
GC> > maybe, even as either an absolute number, a number in percents or a number
GC> > in bp, e.g. using something like
GC> > 
GC> >   [....0.12] [bp ⇓]
GC> >                     abs
GC> >                     pct
GC> > 
GC> > where the right hand side of the cave painting^W^W ASCII diagram 
represents
GC> > an opened combobox?
GC> 
GC> I don't think we'd want a combobox for this. To enter a percentage,
GC> users would type digits on the keyboard and then pick up the mouse
GC> to manipulate the combobox, and that just seems too cumbersome. (We
GC> could tell them how to open a dropdown combobox with Alt-Down, but
GC> they're still going to use the mouse.)

 Yes, but I think the only people who are really bothered by this would be
those who already know how to use keyboard (in addition to Alt-Down or F4,
you could also type "b", "a" or "p/%" to select the corresponding entry
quickly). And those who are not, are unlikely to find this cumbersome (as
difficult as it might be to imagine for you or me).

GC> From time to time I think of allowing text suffixes like '%' and then
GC> parsing "3.5%" as 0.035 . After all, lmi already accepts "3.5e-2" and
GC> stores such a string literally in XML, so it reappears when a saved
GC> file is reopened. We could even use 'bp' or '%%' for permyriad.

 I thought about this and it's indeed a possibility. The advantage of using
a combobox is that it's discoverable: even if the initial control contents
were "xxx bp", showing that such suffix could be used, I don't think many
people would think to enter "%" into it. And if you want to use absolute
values by default (do you?), then even "bp" suffix would be completely
undiscoverable.

GC> That would be kind of like what spreadsheets do.

 Spreadsheets are generic, but I'm not sure if they're really the best
model for specific data entry.

GC> The problem with doing what spreadsheets do is that we'd have to
GC> emulate what spreadsheets actually do, which is a lot of work...and
GC> someone will still insist that the behavior is wrong.

 Yes, I don't think it's worth it. But I still think it's highly worth
providing some way of entering values that people are used to seeing in bp
using their natural format.

 Maybe we could use a compromise solution: instead of using a standalone
combobox, show the units in a sort of icon (like in the search control,
except on the right) that, when clicked, would show a popup menu allowing
to select a different unit. Popup menus are used a lot in lmi UI, so this
should be familiar to lmi users.

 What do you think?
VZ