EiffelBase class
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Eiffel Class
indexing
description: "Formatter for non-integral numbers";
status: "See notice at end of class";
names: format_double;
date: "$Date: 2007-03-30 11:10:11 -0800 (Fri, 30 Mar 2007) $";
revision: "$Revision: 95354 $"
class FORMAT_DOUBLE
inherit
FORMAT_INTEGER
rename
make as set_defaults,
split as split_integral,
formatted as fm_formatted
export
{NONE} fm_formatted
redefine
comma_separate, underscore_separate, remove_separator
end;
DOUBLE_MATH
export
{NONE} all
end
creation
make
feature -- Initialization
make (w, d: INTEGER) is
require
reasonable_field: w >= 1;
reasonable_decimals: d <= w
do
set_defaults (w);
decimals := d;
decimal := '.'
ensure
blank_fill: fill_character = ' ';
show_sign_negative: show_sign_negative;
no_separator: no_separator;
width_set: width = w;
right_justified: right_justified;
leading_sign: leading_sign;
decimals_set: decimals = d;
decimal_point: decimal = '.'
end;
feature -- Access
after_decimal_separate: BOOLEAN;
-- Use separators after the decimal?
decimals: INTEGER;
-- Number of digits after the decimal point.
zero_not_shown: BOOLEAN;
-- Show 0.5 as .5 or 0.5?
decimal: CHARACTER;
-- What is used for the decimal
feature -- Status setting
point_decimal is
-- Use . as the decimal point.
do
decimal := '.'
ensure
decimal = '.'
end;
comma_decimal is
-- Use , as the decimal point.
do
decimal := ','
ensure
decimal = ','
end;
set_decimals (d: INTEGER) is
-- d decimals to be displayed.
require
d <= width
do
decimals := d
ensure
decimals = d
end;
separate_after_decimal is
-- Use separators after the decimal.
do
after_decimal_separate := true
ensure
after_decimal_separate
end;
no_separate_after_decimal is
-- Do not use separators after the decimal.
do
after_decimal_separate := false
ensure
notafter_decimal_separate
end;
underscore_separate is
-- Set the separator to be underscore.
do
separator := '_';
separate_after_decimal
ensure
after_decimal_separate
end;
comma_separate is
-- Set the separator to be comma.
do
separator := ',';
separate_after_decimal
ensure
after_decimal_separate
end;
remove_separator is
-- Remove the separator.
do
separator := '%U';
no_separate_after_decimal
ensure
notafter_decimal_separate
end;
show_zero is
-- Show 0.5 as 0.5 .
do
zero_not_shown := false
ensure
notzero_not_shown
end;
hide_zero is
-- Show 0.5 as .5 .
do
zero_not_shown := true
ensure
zero_not_shown
end;
feature -- Conversion
formatted (d: DOUBLE): STRING is
-- Format d.
local
sign: INTEGER;
integral, fraction: DOUBLE;
ints, fracs: STRING;
value: DOUBLE
do
value := d;
sign := 1;
if d < 0 then
sign := -1;
value := -value
end;
value := value + 5 * 10 ^ (-decimals - 1);
integral := floor (value);
fraction := floor ((value - integral) * 10 ^ (decimals + 1));
if notno_separator then
ints := split_integral (integral.out);
if after_decimal_separate then
fracs := separate_fraction (pad_fraction (fraction))
else
fracs := pad_fraction (fraction)
end
else
ints := clone (integral.out);
fracs := pad_fraction (fraction)
end;
create Result.make (width);
if integral /= 0 or else notzero_not_shown then
Result.append (ints)
end;
Result.extend (decimal);
if decimals > 0 then
Result.append (fracs)
end;
if notignore_sign then
Result := process_sign (Result, sign)
end;
if justification /= no_justification and then Result.count < width then
Result := justify (Result)
end
ensure
exists: Result /= void;
correct_width: Result.count >= width
end;
feature {NONE} -- Implementation
pad_fraction (f: DOUBLE): STRING is
-- Stretch or shrink f to length decimals .
do
Result := f.out;
Result.head (Result.count - 1);
if Result.count > decimals then
Result := Result.substring (1, decimals)
else
from
until
Result.count = decimals
loop
Result.precede ('0')
end
end
ensure
Result.count = decimals
end;
separate_fraction (s: STRING): STRING is
-- Apply separators to the fraction.
require
efficiency: separator /= '%U'
local
count, sep_length: INTEGER
do
from
count := 1;
create Result.make (width)
until
count > s.count - 3
loop
from
sep_length := 0
until
sep_length = 3
loop
Result.extend (s.item (count));
count := count + 1;
sep_length := sep_length + 1
end;
Result.extend (separator)
end;
from
until
count > s.count
loop
Result.extend (s.item (count));
count := count + 1
end
end;
invariant
separate_all: no_separator implies notafter_decimal_separate;
end -- class FORMAT_DOUBLE
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