Derek Peschel 2005-04-27 This started as A little calculator and got transformed to meet my goals:
This is a feature I've wanted for a long time. With modern software and fonts, I see no reason for displaying e notation to the user in the final result. (Intermediate results, and communications between programs, are another matter.)
Calculator keyboard layouts work well on calculators. But on a computer I'd rather use a computer keyboard. Having a calculator layout, and being forced to use the mouse, is doubly inefficient. But getting rid of the screen layout, or making it unresponsive to the mouse, gets rid of the free online help you already have. And forcing the functions to match the keypad wouldn't work well either. You don't need enter and =. So this is a compromise: the positions work with the keypad layout, but the help and some of the functions remain. And the main part of the keyboard needs to work too. Later, a way to hide the buttons or put them in a separate window would be good.
Again, why not use hardware like the nice big screen you almost certainly have? The split may make selection and cursor placement more intuitive too (but I need more evidence). And it makes the scientific-notation feature more reliable. The color feature just sort of happened along the way.
Mysterious bugs:
Other changes:
Grand plans for later, from other people's code if it works:
### Constants and variables.
set ::n 0 ;# current button-widget name
set ::c 4 ;# number of columns
set ::upToDateForeground black ;# for result that has just been computed
# when expression is shown, and for
# expression that can be edited
set ::staleForeground gray ;# for result that remains from last
# calculation but expression isn't shown,
# or for expression that can't be edited
set ::errorForeground red ;# for result after a Tcl error
set ::staleErrorForeground darkred
# for stale erroneous result
## As well as representing colors, these change the behavior of procedures.
set ::estate notDone ;# notDone (can be edited,
# upToDateForeground) or done (can't be
# edited, staleForeground)
set ::rstate upToDate ;# upToDate or stale or error or staleError
# as explained next to colors
array set superscripts {
0 \u2070
1 \u0089
2 \u0082
3 \u0083
4 \u2074
5 \u2075
6 \u2076
7 \u2077
8 \u2078
9 \u2079
+ \u207A
- \u207B
}
# 1 2 3 4
set superscriptRE {^([-+]?[0-9]+(?:\.[0-9]+)?)(?:[DdEe]([-+]?[0-9]+))?$}
# 1 is sign, integer, fraction if any; integer. with no fraction is not
# allowed
# 2 is fraction if any, an operand to the ? afterward, not returned
# by regex because of the ?: modifier
# 3 is exponent character, exponent sign, exponent, not returned by regex
# because of the ?: modifier
# 4 is the part of 3 that I want to translate to Unicode
## Widgets created later: .e is the expression (an entry widget)
## and .r is the result (a second entry widget). .0 through .17
## are the buttons.
### Set the window title.
wm title . Calculator
### Create buttons but don't do anything with them yet.
## keypad button widget names
## layout and "grid" command args
##
## c = / * .0 .1 .2 .3
## 7 8 9 - .4 .5 .6 .7
## 4 5 6 + .8 .9 .10 .11
## 1 2 3 e .12 .13 .14 .15
## 0 . .16 - .17 ^
##
## c represents "clear"
## e represents "enter"
##
## button purposes like keypad except enter position is = purpose
## and = position is exponent purpose
foreach key {
C e / *
7 8 9 -
4 5 6 +
1 2 3 =
0 .
} {
## Set each key's button's text.
## "default" applies to C 7 8 9 4 5 6 + 1 2 3 = 0 . keys
switch -- $key {
e {set keytext "\u00d710\u207F"}
/ {set keytext "\u00f7"} - {set keytext "\u2212"}
default {set keytext $key}
}
## Set each key's button's command. See "procedures" below.
## "default" applies to e / * 7 8 9 - 4 5 6 + 1 2 3 0 . keys
switch -- $key {
C {set cmd clearboth}
= {set cmd =}
default {set cmd "hit $key"}
}
## Create a button with the text and command as just set.
## The grid manager changes a button's width automatically,
## but not its height, so do that now.
if [expr $::n == 15] {
button .$::n -text $keytext -command $cmd -width 4 -height 2
} else {
button .$::n -text $keytext -command $cmd -width 4
}
incr ::n
}
### Lay out the entry widgets and buttons in a grid.
## Macintosh system dependency -- This is the only font I've found
## with superscripts that are all the same size.
grid [entry .e -textvar e -font {{Hoefler Text} 24} -just left] \
-sticky we -columnspan $::c -pady 5
grid [entry .r -font {{Hoefler Text} 24} -just right] -sticky we \
-columnspan $::c -pady 5
grid .0 .1 .2 .3
grid .4 .5 .6 .7
grid .8 .9 .10 .11
grid .12 .13 .14 .15
grid .16 - .17 ^
grid configure .0 -sticky we
grid configure .1 -sticky we
grid configure .2 -sticky we
grid configure .3 -sticky we
grid configure .4 -sticky we
grid configure .5 -sticky we
grid configure .6 -sticky we
grid configure .7 -sticky we
grid configure .8 -sticky we
grid configure .9 -sticky we
grid configure .10 -sticky we
grid configure .11 -sticky we
grid configure .12 -sticky we
grid configure .13 -sticky we
grid configure .14 -sticky we
grid configure .15 -sticky nsew
grid configure .16 -sticky we
grid configure .17 -sticky we
### Probably Macintosh system dependency -- Bind keyboard keys.
### Focus will be set later, and we assume it is never reset.
bind .e <Key-Num_Lock> clearboth
bind .e <Key-c> clearboth
bind .e <Key-KP_Equal> "hit e"
bind .e <Key-e> "hit e"
bind .e <Key-KP_Divide> "hit /"
bind .e <Key-/> "hit /"
bind .e <Key-KP_Multiply> "hit *"
bind .e <Key-*> "hit *"
bind .e <Key-KP_7> "hit 7"
bind .e <Key-7> "hit 7"
bind .e <Key-KP_8> "hit 8"
bind .e <Key-8> "hit 8"
bind .e <Key-KP_9> "hit 9"
bind .e <Key-9> "hit 9"
bind .e <Key-KP_Subtract> "hit -"
bind .e <Key-minus> "hit -"
bind .e <Key-KP_4> "hit 4"
bind .e <Key-4> "hit 4"
bind .e <Key-KP_5> "hit 5"
bind .e <Key-5> "hit 5"
bind .e <Key-KP_6> "hit 6"
bind .e <Key-6> "hit 6"
bind .e <Key-KP_Add> "hit +"
bind .e <Key-plus> "hit +"
bind .e <Key-KP_1> "hit 1"
bind .e <Key-1> "hit 1"
bind .e <Key-KP_2> "hit 2"
bind .e <Key-2> "hit 2"
bind .e <Key-KP_3> "hit 3"
bind .e <Key-3> "hit 3"
bind .e <Key-KP_Enter> =
bind .e <Key-Return> =
bind .e <Key-KP_0> "hit 0"
bind .e <Key-0> "hit 0"
bind .e <Key-KP_Decimal> "hit ."
bind .e <Key-period> "hit ."
### Procedures that widgets call.
proc clearboth {} {
focus .e
set ::e ""
.e config -foreground $::upToDateForeground
set ::estate notDone
set ::r ""
setr
.r config -foreground $::upToDateForeground
set ::rstate upToDate
}
proc = {} {
focus .e
.e config -foreground $::staleForeground
set ::estate done
if {![catch [set ::r [expr [string map {* *1.0* / *1.0/} $::e]]]]} {
# what value should r show? its previous one? expr's best nuemrical
# approximation? text of the error?
.r config -foreground $::errorForeground
# is this really a good idea?
setr
set ::rstate error
} else {
.r config -foreground $::upToDateForeground
setr
set ::rstate upToDate
}
}
proc hit {key} {
focus .e
switch -- $::estate {
notDone {
.e insert end $key
.e icursor end
}
done {
if [regexp {[-+*/]} $key] {
set ::e $::r
} else {
set ::e ""
}
.e insert end $key
.e icursor end
set ::estate notDone
.e config -foreground $::upToDateForeground
}
default {
# ignore for now
}
}
switch -- $::rstate {
upToDate {
.r config -foreground $::staleForeground
set ::rstate stale
}
stale {
# remains stale
}
error {
.r config -foreground $::staleErrorForeground
set ::rstate staleError
}
staleError {
# remains staleError
}
default {
# ignore for now
}
}
}
### Subroutines.
proc setr {} {
# Hopefully end will be rounded, as described in manual
.r delete 0 end
set ignored ""
set mantissa ""
set exponent ""
set rdisplay ""
if {[regexp $::superscriptRE $::r ignored mantissa exponent]} {
if {[string length $exponent] > 0} {
set unicodeExponent [string map [array get superscripts] $exponent]
set rdisplay "$mantissa \u00d710$unicodeExponent"
} else {
set rdisplay $mantissa
}
}
.r insert end $rdisplay
}
### Main loop.
encoding system utf-8
focus .e
wm resizable . 0 0