Trouble with custom validation of Rails app - ruby-on-rails

I'm making a web app where the point is to change a given word by one letter. For example, if I make a post by selecting the word: "best," then the first reply could be "rest," while the one after that should be "rent," "sent", etc. So, the word a user enters must have changed by one letter from the last submitted word. It would be constantly evolving.
Right now you can make a game and respond just by typing a word. I coded up a custom validation using functionality from the Amatch gem:
http://flori.github.com/amatch/doc/index.html
Posts have many responses, and responses belong to a post.
here's the code:
def must_have_changed_by_one_letter
m = Amatch::Sellers.new(title.strip)
errors.add_to_base("Sorry, you must change the last submitted word by one letter")
if m.match(post.responses.last.to_s.strip) != 1.0
end
When I try entering a new response for a test post I made (original word "best", first response is "rest") I get this:
ActiveRecord::RecordInvalid in ResponsesController#create
Validation failed: Sorry, you must change the last submitted word by one letter
Any thoughts on what might be wrong?
Thanks!

Looks like there are a couple of potential issues here.
For one, is your if statement actually on a separate line than your errors.add_to_base... statement? If so, your syntax is wrong; the if statement needs to be in the same line as the statement it's modifying. Even if it is actually on the correct line, I would recommend against using a trailing if statement on such a long line; it will make it hard to find the conditional.
if m.match(post.responses.last.to_s.strip) != 1.0
errors.add_to_base("Sorry, you must change the last submitted word by one letter")
end
Second, doing exact equality comparison on floating point numbers is almost never a good idea. Because floating point numbers involve approximations, you will sometimes get results that are very close, but not quite exactly equal, to a given number that you are comparing against. It looks like the Amatch library has several different classes for comparing strings; the Sellers class allows you to set different weights for different kinds of edits, but given your problem description, I don't think you need that. I would try using the Levenshtein or Hamming distance instead, depending on your exact needs.
Finally, if neither of those suggestions work, try writing out to a log or in the response the exact values of title.strip and post.responses.last.to_s.strip, to make sure you are actually comparing the values that you think you're comparing. I don't know the rest of your code, so I can't tell you whether those are correct or not, but if you print them out somewhere, you should be easily able to check them yourself.

Related

(wx)Maxima: determining the number of parts of an expression

I'd like to use part to handle expressions of different length but have not been able to find anything in the documentation that addresses how to determine the number of parts of an expression.
I do have an upper bound for the number of parts so, in this particular case, I could loop over the terms until I get an error; however, I was wondering if there is a more direct method?
I can't believe this, but it appears length does the trick.
I assumed it was limited to lists because it returns an error for single numbers, because they are atoms. Apparently my brain decided "doesn't work with atoms" to mean "only work with lists."
However, this does mean that neither part nor length will work if the expression only has one part, so that case has to be handled separately.
I would still be interested in knowing if there is a solution that will work in all cases, so I won't mark this as the answer, just yet.

How to handle homophones in speech recognition?

For those who are not familiar with what a homophone is, I provide the following examples:
our & are
hi & high
to & too & two
While using the Speech API included with iOS, I am encountering situations where a user may say one of these words, but it will not always return the word I want.
I looked into the [alternativeSubstrings] (link) property wondering if this would help, but in my testing of the above words, it always comes back empty.
I also looked into the Natural Language API, but could not find anything in there that looked useful.
I understand that as a user adds more words, the Speech API can begin to infer context and correct for these, but my use case will not work well with this since it will often only want one or two words at most, limiting the effectiveness of context.
An example of contextual processing:
Using the words above on their own, I get these results:
are
hi
to
However, if I put together the following sentence, you can see they are all wrong:
I am too high for our ladder
Ideally, I would either get a list back containing [are, our], [to, too, two], [hi, high] for each transcription segment, or would have a way to compare a string against a function that supports homophones.
An example of this would be:
if myDetectedWord == "to" then { ... }
Where myDetectedWord can be [to, too, two], and this function would return true for each of these.
This is a common NLP dilemma, and I'm not so sure what might be your desired output in this application. However, you may want to bypass this problem in your design/architecture process, if possible and if you could. Otherwise, this problem is to turn into a challenge.
Being said that, if you wish to really get into it, I like this idea of yours:
string against a function
This might be more efficient and performance friendly.
One way, I'd be liking to solve this problem would be though RegEx processing, instead of using endless loops and arrays. You could maybe prototype loops and arrays to begin with and see how it works, then you might want to use regular expression for gaining performance.
You could for instance define fixed arrays in regular expressions and quickly check against your string (word by word, maybe using back-referencing) and you can add many boundaries in your expressions for string processing, as you wish.
Your fixed arrays also can be designed based on probabilities of occurring certain words in certain part of a string. For instance,
^I
vs
^eye
The probability of I being the first word is much higher than that of eye.
The probability of I in any part of a string is higher than that of eye, also.
You might want to weight words based on that.
I'd say the key would be that you'd narrow down your desired outputs as focused as possible and increase accuracy, [maybe even with 100 words if possible], if you wish to have a good/working application.
Good project though, I hope you like/enjoy the challenge.

iOS DDMathParser Get Any Occurrences of (...) In String

I am using DDMathParser in my app, and have recently come across the need to get occurrences of any group of numbers within a () parentheses bracket thingy (very highly technical!). For example, I would need to get (6+5) out of 6+7/8(6+5). Specifically, I would like to be able to do this so that I can make (56+9)sqrt compile just as well as sqrt(56+9). Any help?
P.S. I know that the maker of DDMathParser is often sighted in this neck of the woods. I am secretly hoping that he will come to the rescue and either fix my problem so I can implement it myself or him make it part of DDMathParser! :)
So, I've thought a lot about this question since you posted it a month ago. From what I understand, you're constructing a string as the user clicks/taps buttons.
I think this is your problem.
As the user taps buttons, you should be constructing (or modifying) DDExpression objects. This is the "pure" format of a math expression, whereas a string is lossy and difficult to manipulate. The string you show to the user should be generated from the DDExpression tree you're building.
This is a complex problem, and I'm still not entirely sure how I would go about implementing this, but this is the root of how I'd do it. I would not just construct a string based on what the user types.

regex for a full name

I've recently been receiving a lot of first name only entries in a form. While maybe I should have had 2 separate first and last name fields this always seemed to me a bit much. But I would like to try and get a full name which basically can only be determined by having at least one space.
I came up with this, but I'm wondering if someone has a better and possibly simpler solution?
/([a-zA-ZàáâäãåèéêëìíîïòóôöõøùúûüÿýñçčšžÀÁÂÄÃÅÈÉÊËÌÍÎÏÒÓÔÖÕØÙÚÛÜŸÝÑßÇŒÆČŠŽ∂ð,.'-]{2,}) ([a-zA-ZàáâäãåèéêëìíîïòóôöõøùúûüÿýñçčšžÀÁÂÄÃÅÈÉÊËÌÍÎÏÒÓÔÖÕØÙÚÛÜŸÝÑßÇŒÆČŠŽ∂ð,.'-]{2,})/
This is basically this /([a-zA-Z,.'-]) ([a-zA-Z,.'-])/ plus unicode support.
I'd first make sure that you really do need people to give you a last name. Is that a genuine requirement? If not, I'd skip it because it adds unnecessary complication and barriers to entry. If it really IS a requirement, it probably makes sense to have separate first and last name fields in your UI so that it's explicit.
The fact that you didn't do that to begin with suggests that you might not really need the last name as much as you think you do.
To answer your original question, this expression might give you what you're looking for without the guesswork:
/[\w]+([\s]+[\w]+){1}+/
It checks that the string contains at least 2 words separated by whitespace. Like Tim Pietzcker pointed out, validating the words themselves is prone to error.
In Ruby 1.9, you have access to Unicode properties (\p{L} is a Unicode letter). But trying to validate a name in any way (regex or not) is prone to failure because names are not what you think they are.
Your theory that "if there's a space, there must be a last name there" is incorrect, too - think of first and middle names...

TEXT Update versus TEXT insert on Informix Dynamic Server

I maintain a 3rd party Informix driver that's written with ESQL-style (Informix API) calls. I'm working on a bug where, for TEXT fields, INSERTs work fine and UPDATEs fail. Stepping through the code, what I've found is that we're checking our sqlda structure to tell us whether and how to bind, and after the call to sqli_describe_statement, the sqlda.sqld variable contains 2, the correct number of bound parameters for this insert call, and the parameters appear to be set up correctly whereas in the update case, the number returned is 0, with no parameter information (it should be 1, for the one param in: "UPDATE TESTTAB SET COLNAME = ? WHERE OTHERCOLNAME = 1 ").
Using the sqlda information, we correctly set up the required locator structure for the INSERT, but we can't for the update because the information isn't there. If I fake it out in the debugger and run the set-up-the-locator code for the update, it updates fine.
The statement certainly appears correct, and the same variable is being used for the INSERT as the UPDATE bind. Moreover sqli_prep has no problem with the update. For the describe, sqsla.code returns different non-negative numbers 4 and 6, representing the different types of statements being described, as documeneted (i.e., not an error code), so there's no obvious problem there.
Is there something else I should be checking in the code ahead of this that might cause this weird behavior (other than special case handling for the different queries -- nothing there)
Am I missing something fundamental here about how one does UPDATEs on TEXT fields, such as you have to create a locator object, find the row, and click your heels together three times and say "There's no place like IBM?"
So far Google Fu has turned up little in the documentation, but if you know of docs or samples that point the way, that's cool too.
This is one of the murky areas of Informix behaviour. The behaviour of DESCRIBE is supposed to describe output parameters (it is a shorthand for DESCRIBE OUTPUT stmt INTO ...); to describe the input parameters, you would use DESCRIBE INPUT stmt INTO ... instead.
However, for various reasons extending back to the dawn of time (well, 1985, anyway), the INSERT statement got a special case exemption and plain DESCRIBE described its input parameters - unlike UPDATE or DELETE (or, these days, MERGE).
So, your code was probably written before DESCRIBE INPUT and DESCRIBE OUTPUT became feasible (that was circa 2000±3 years). In principle, using the directed DESCRIBE statements should fix the issue. There may be an ONCONFIG parameter to be set to get this behaviour.
I remember being grateful that the feature arrived, but also I remember thinking "Damn, I'm not going to be able to use that for a while - until the old versions without it are all retired". I think that has basically happened now - IDS 7.31 in particular is now obsolete, and so indeed are the IDS 9.x versions, so all available versions of IDS support the feature. OnLine 5.20 - a minority interest - still doesn't and won't ever support it. So, I need to review how to update my programs such as SQLCMD to exploit this. The code there includes what I call 'vignettes'; they're complete little programs that illustrate how to work with BYTE and TEXT blobs. You might find UPDBLOB or APPBLOB, for example, of some use.

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