2011-05-31

explicitely expressable state

5.10: adda/images for every data value:
5.4: 5.10: 5.30:
. each value may be associated with
# an icon (iconic image):
. optional .
# a symbol (linguistic image):
--[5.31: ada calls this the image]
. all types can be represented as text:
eg, just as enum's have names for each value,
and numbers have a sequence of digits,
graphics have a matrix of color records,
each of which is a list of tagged numbers:
(red:1, green:2, blue:3).
# a digital value (representation);
--[5.31: ada calls this the enum`value
or the structure`representation]
ie, some structure of bit arrays,
where structuring can be done by
pointers or arrays .
[5.31: structures can be equal if they have
the same type, and equal components;
they can also be tested for less-than
with components treated like string characters .]
. a type may choose to hide its implementation;
[@] addx/info'hiding vs blackbox binaries
[5.31: however,
the system can store snapshots of itself,
with each object represented by
a particular string of integers;
which a private type can interpret in various ways .]
5.10: 5.30:
. given the type streetlight.type =
{off:0, red:1, yellow:2, green:3};
the image of red is the text "(red);
and its value is the integer: 1;
. red could have an icon colored red .