Advice and opinions?
Ron Phillips
Adam McCrea
- Adam
Ron Phillips
Aaron Bedra
Adam McCrea
If the flags don't change very often, and if the programmer (you) is the one responsible for keeping them updated, I'd still maintain the flag mappings in the code rather than in the DB. I'd put them in their own module somewhere so they don't get buried, but the only reason I see to keep them in the DB is so that a user can maintain them, or if they change so often that you create an administrative interface to reduce the time it takes for you to update them.
Good luck!
- Adam
Matt Williams
In order to use it, you'd do a:
class RoadCondition << ActiveRecord::Base
class_attr_lookup
end
The class_attr_lookup code is:
class Module
def class_attr_reader(*symbols)
symbols.each do |symbol|
self.class.send(:define_method, symbol) do
self.class_eval "@@#{symbol}"
end
end
end
def class_attr_writer(*symbols)
symbols.each do |symbol|
self.class.send(:define_method, "#{symbol}=") do |value|
self.class_eval "@@#{symbol} = value"
end
end
end
def class_attr_accessor(*symbols)
class_attr_reader(*symbols)
class_attr_writer(*symbols)
end
def class_attr_lookup
self.find(:all).each do |rec|
r = rec.name.downcase.underscore
class_attr_reader(r)
self.class_eval "@@#{r} = rec"
end
end
end
--
I can say to myself and the world, "Look at all I am doing, am I not being busy? Am I not contributing? Am I not having an impact on all those around me and with whom I come into contact? See, my life has meaning."
To which the Tao responds, "You are doing, yes, but you are not being. Slow down, go with the flow, work with life, not against it. By being, you do. By doing, you cease to be."
Ron Phillips
>>> "Matt Williams" <otte...@gmail.com> 08/08/2007 2:26 PM >>>
Ron Phillips
Joe OBrien
Aaron Bedra
jherber
user, you want to convert from a flag value to a human readable value
and visa-versa when taking input from a user and storing the
solution. so, i see "Flag" class with two simple functions that
encode and decode, backed by an easy to edit yaml table (in case the
interpretation of a flag needs to be modified). thus, when you render
the model you call "decode" and when you accept input, you call
"encode".
now, if you have families of flags, you should probably have a class
for each type all wrapped in one module (e.g.
"UserFlags::SecondaryRoadConditions.decode(x)" ) . imo, yes meta-
programming is cool, but it should not be considered unless it is
keeps the intention of the code obvious and is significantly cheaper
(in terms of time to implement and support).
best,
jim herber
Ron Phillips
FLAGS = {"occurrence"=>{
'1' => 'On Roadway',
'2'=>'On Shoulder',
'3'=>'In Median',
'4'=>'On Roadside',
'5'=>'On Gore',
'6' =>'Outside Trafficway',
'7' =>'Unknown'}
}
FLAGS[flag][key]
end
def decode(flag, value)
FLAGS[flag].index(value)
end
def flaglist
FLAGS
end
end
FACADE_RE = /(facade_)(\w+)(=?)/
FLAGGER = Flagger.new
facade = FACADE_RE.match(m.to_s)
if facade
message = facade[2]
suffix = facade[3]
#first, handle facade requests where a facade exists
if FLAGGER.flaglist.has_key? message
args[0]=FLAGGER.decode(message, args[0]) unless args[0].nil?
suffix.nil? ? result=super(message) : result=super(message+suffix, args)
#return the (possibly new) facade value
FLAGGER.encode(message,result)
else
#if there's no facade available, just return the value
super(message)
end
else
#it's not a facade request, just pass it along
super(m, *args, &block)
end
end
end
#~ 2005400453
puts c.facade_docno
#~ 2005400453
puts c.occurrence
#~ 1
puts c.facade_occurrence
#~ On Roadway
puts c.facade_occurrence = 'On Gore'
#~ On Gore
puts c.occurrence
#~ 5
puts c.occurrence = 1
#~ 1
>>> jherber <jimh...@gmail.com> 08/09/2007 8:15 AM >>>
Ken Barker
Ken Barker
EdgeCase
http://theEdgeCase.com
Ron Phillips
Anyone else hoping that 'On Gore' means something different than expected? ;-)
Adam McCrea
Ron Phillips
Lari Kirby
Lari Kirby
--
Footsteps in the sands of time are not made by sitting down.
---
The greatest glory does not exist in never falling, but in rising every time we fall.
---
Mathematicians are lazy: they prove something once and then take it as given from then on. - Hal Hanes, Math Professor (paraphrased)
---
"Why program by hand in five days what you can spend five years of your life automating?" - Terence Parr, creator of ANTLR
----- Original message -----
From: "Ron Phillips" <RPhi...@engineer.co.summit.oh.us>
To: colum...@googlegroups.com
Date: Thu, 09 Aug 2007 13:25:01 -0400
Subject: [CRB] Advice and opinions?
Ok, I checked with my traffic buddies. "Gore" has several meanings, as you point out. It's 'bloody' awkward, no 'bull', but in traffic talk, the "gore" of a road is like a person's "taint," except it's a road -- tain't the expressway, tain't the exit. That triangle of grass is the 'gore' of the exit. Who knew?
Ron
>>> "Ken Barker" <ken.b...@gmail.com> 08/09/2007 1:11 PM >>>
Anyone else hoping that 'On Gore' means something different than expected? ;-)
Mike Sandman
nice discussion. first let me offer a link to some reference material.
http://www.dps.state.oh.us/CrashRequests/Common/CrashTTDoc.pdf
i personally find the two most fun things i do is acquiring new tools
and choosing the perfect tool for the job. it is the mark of a
craftsman. of course, you can always use a general purpose tool, if
that's all you have. in my wood shop, when i am cutting veneer i reach
for my veneer saw, even though the table saw or band saw would also
work, just not as well.
as i read all of the posts, i am reminded of the old saying, "when all
you have is a hammer, everything looks like a nail." so let me offer a
(likely unpopular...lol) opinion suggesting you put the ruby
sledge-hammer back in the tools box and take this opportunity to learn a
new specialty tool. and don't even think about reaching for the
swiss-army chainsaw a.k.a perl :) as an old timer in coding terms (25+
years) i have quite a large tools box--not bragging, i'm just old ;)
and, i encourage you to enlarge yours.
anyway, back to your problem. your are parsing data from lines of texts.
i doubt you will be getting little snippets of text hundreds of times
per day. you will likely want to bulk process the in-coming text data
in a single, simple, quick process. this begs to be processed as a
stream, of course. there are many tools to do this and many approaches
to building your parser. however, i think the key factor here is that
you will likely write this script, and then use it for long periods of
time. time enough to "forget" exactly how it works--perhaps you might
not even be the next person to modify it.
so, you need a tool that adds very little cruft around the job of
parsing and "decoding" your field data. in fact, the perfect tool will
help you to see the rules and definitions of of parsing (your grammar)
at-a-glance. this is where the general-purpose languages fall down.
that said, i will not tell you which tool you should pick, that's part
of the fun. but i will leave you with this small example to amplify my
point.
on page 6 of the PDF above, column 3 gives you the field lengths. using
that information, the following awk script will parse a tractape file in
to a tab separated values file. note i only used the first 10 fields
for example brevity i.e. laziness ;)
BEGIN { OFS = "\t"
FIELDWIDTHS = "11 10 5 2 2 1 1 2 5 1" }
{ print $1, $2, $3, $4, $5, $6, $7, $8, $9, $10 }
i doubt even Ruby can be more succinct then that! almost anyone with
minimal programming experience can quickly grasp that this 3 line script
will (on line 1) use tabs to separate values and (on line 2) split
fields at fixed intervals of 11 10 5 etc. obviously, the print
statement (on line 3) could be turned into a loop rather than explicitly
printing each field. though, i kind of like fact that you get a quick
field count from the print statement. moreover, if you wanted to wrap
some extra text around certain fields, it would be trivial even for a
first year programming student.
my point? that, using the right tool for the job makes the job
wonderfully simple and fun. okay, okay, this is a Ruby group, so why
not use Ruby...and i am all for it. just take this little script and
pop it into a system exec statement e.g.
system("cat myfile | awk 'BEGIN {...}'")
and viola!
my two cents...
-sandman
Ron Phillips
Ron Phillips
File.open('lib/flags.yml') do |file|
FLAGLIST = YAML::load(file)
end
FACADE_RE = /(facade_)(\w+)(=?)/
#I want any message that starts with facade_ to return the f_encoded value
#or to set the f_decoded key. So, facade_occurrence should return 'On Road'
#and facade_occurrence='On Gore' should set occurrence = '5'.
def method_missing(m, *args, &block)
facade = FACADE_RE.match(m.to_s)
if facade
message = facade[2]
suffix = facade[3]
#first, handle facade requests where a facade exists
args[0]=f_encode(message, args[0]) unless args[0].nil?
#return the (possibly new) facade value
else
#if there's no facade available, just return the value
super(message)
end
else
#it's not a facade request, just pass it along
super(m, *args, &block)
end
end
def f_decode(flag, key)
FLAGLIST[flag][key]
end
def f_encode(flag, value)
FLAGLIST[flag].index(value)
end
end
"#{obj.send(message)} - #{obj.send('facade_'+message)}"
end
//////////////////////////////////////////
result = "<select name='#{name}[#{method}]'>\n"
collection = object.class::FLAGLIST[method]
collection.keys.sort.each do |key|
if object.send(method) == key
result << "<option value='#{key}' selected='selected'>#{collection[key]}</option>\n"
else
result << "<option value='#{key}'>#{collection[key]}</option>\n"
end
end
result << "</select>\n"
return result
end
//////////////////////////////////////
<option value='1'>Straight Level</option>
<option value='2' selected='selected'>Straight Grade</option>
<option value='3'>Curve Level</option>
<option value='4'>Curve Grade</option>
<option value='5'>Unknown</option>
</select>
Thanks again, everyone.
Ron