What is an "active" statement in MySQL? - mysql

An interviewer just asked me that question, if I was familiar with "active" statements.
I then asked if she was referring to prepared statements, and she said no, I had no other choice but to answer "I'm sorry, but I'm not familiar with them".
It seemed like it was not important at all, I still got a second interview.
However, after googling the question I haven't been able to find a reference to "active" statements.
I should have asked for the answer, but then again since it was an interview it would have not been an appropriate question.
Does anyone around here have a clue?
Thanks a bunch!
P.S. If this is not a good question for the community, feel free to close or delete the thread!

Did they maybe mean "Active Record?" That's an object-relational mapping technique, used to match model-tier code to data code, and uses automatically generated SQL statements.

Related

resource and references for one/many to many relationship in graphql?

i feel like im going crazy here. spent the last couple hours searching and there is not one single official or complete source of information on this topic. all that i have found are vague 10 line of code representations of how relationships would look in the typedefs but no implementation details anywhere!
i thought this would be a very common use case in graphql. why is nobody talking about it?
are there any resources you can recommend on implementing o2m and m2m relationships? am i thinking of this wrong and this isnt something graphql supports?
here is the implementation i am stuck on (i believe caused by circular references).
i couldnt get an answer to either of my questions. so i figured it out myself and documented the solution through about 20 commits of refactoring. you can see my original question that led me to seeking relationship modeling resources. i answered the question and gave details and links to the refactor.
before someone edits this answer out i believe it does count as an answer. i provided a resource for someone seeking to model relationships in graphql.

How can I help fellow students struggling in programming classes? [closed]

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I'm a computer science student finishing up my second semester of programming classes. I've enjoyed them quite a bit, and learned a lot, but it seems other students are struggling with the concepts and assignments more than I am. When an assignment is due, the inevitable group email comes out the day or two before with people needing some help either with a specific part of the problem, or sometimes people just seem to have a hard time knowing where to start.
I'd really like to be able to help out, but I have a hard time thinking of the right way to give them help without giving them the answer. When I'm having trouble understanding a concept, a code snippet can go along way to helping me, but at the same time if it makes a lot of sense, it can be difficult to think of another way to go about it. Plus the Academic Integrity section of each assignment is always looming overhead warning against sharing code with others. I've tried using pseudo code to help give others an idea on program flow, leaving them to figure out how to implement certain aspects of it, but I didn't get too much feedback and don't know how much it actually helped them out, or if it just confused them further.
So I'm basically looking to see if anyone has experience with this, or good ways that I can help out other students to nudge them in the right direction or help them think about the problem in the right way.
Have them explain their code to you.
This accomplishes several things:
First, it demonstrates that they actually have code to show you. How can they not understand something if they haven't even opened up a text editor yet?
Next, it demonstrates that they understand the code at a basic level. They could have copied it from somewhere. If they don't know the first thing about the code they have, that's a flag. (If they did copy the code, but still took the time to understand the code, then that's still academically dishonest but it's a valuable skill to use after college.)
Finally, now we're at the place where they might actually get it, with your help (or possibly even without!) If they get to the place where the hole in their understanding is (as they're explaining their code to you) and it jumps out at them, then they've solved their own problem. If they don't recognize the hole, then this is where you can give them targeted hints.
I've worked as a TA and at a CS department help desk (and helped buddies). This is what I do...
Abstract out the issue, find a related problem, then work through the related problem with them. If they can't make the connection, you can't really help them.
Edit: and refuse to help with more than the bare basic syntax if they are looking for help the day of or day before. Things should have been dealt with long before deadline. Crutching people on the day-of is not a good practice for you.
Some thoughts:
Do pair programming
Have the student (the person you are helping) sit in the chair and code something. Could be a code snippet, could be a portion of a project, anything, as long as it represents something they have trouble on. As they go, point out (not rudely) places where they may have done something incorrectly, or something that could be improved upon.
Review work done
One of the things that helped me the most was to have a peer (as opposed to a teacher or student aide) review my code. Most of the time the peer could point out places where they might have done something differently.
Make them repeat you.
I often make people I'm helping learn repeat what I just said to see if they understand it or have any questions. You would be surprised how often people don't speak up when they don't understand something.
Offer help before the project is due.
Trying to get the project done the night before it is due is a surefire way to, at the very least, not learn the concepts as thoroughly as you might have otherwise.
Don't code it yourself
Your peers will learn nothing if you do it for them.
Find other resources
An aide, a friendly professor, another one of your peers can be invaluable resources. If you find that your style of teaching doesn't mesh well with one of your peers' style of learning, point them toward someone else who might be able to help them more.
Hope for the best
You can only go so far when teaching someone; they have to want to learn.
One thing that might be helpful to your fellow students is to point to similar code in the lecture notes (or if you don't get lecture notes handed out, in your own notes). That way you're only showing them what the professor said, but doing it in a helpful way.
If another student is open to it, asking them questions about everything they've tried and why would be helpful.
Finally, consider going to your professor and asking for his or her input on what you are allowed to do and how they might suggest you help others. After all, professors have years of experience in teaching students. Even more, will you have an opportunity as an undergraduate to be a TA in future years? I got to TA as an undergraduate, and that helped me to productively use my impulses to assist others without breaking any honor codes. If you have such undergraduate employment opportunities, letting professors see you now as the helpful type will help you acquire them.
I don't think you should be helping them. I think it's academically dishonest. Also, it does them no help to have you give them answers, or even to have you be around to answer questions, since once they get to the exam (or the real world), you won't be there for them. They need to not only learn how to program on their own (which presumably you're helping them do), but also get their questions answered on their own. That means posting on places like StackOverflow. You might want to recommend that they formulate a specific question (always a good exercise) and post it on here with the "homework" tag.
When I was taking CS classes in college, there were a number of students who just couldn't code or design at all (and I'm thinking of a senior level software engineering class in particular). They also had no idea how to go about solving problems, or where to look things up, where to get questions answered, or what questions to ask. They were totally helpless because they had spent most of their undergraduate time working on their homework/projects in groups and having the more talented group members hand-hold them. Don't perpetuate this. The last thing the industry needs is more incompetent programmers who graduate with good grades to put on their resume.
Whenever I tried to teach my girlfriend how to program I did almost nothing but ask questions. (she got to the .each statement before getting bored)
Ask them question how their code works and how they think they could accomplish the task. Give them small nudges in the right direction. And never EVER type something for them. If you have another computer and type code on it to show them and show them the results, that is fine but don't over do that.
Here's the advice I give my student teachers: avoid giving answers to students. Instead, ask them questions. And make sure to ask questions that they can ask themselves in the future. For the material I teach, here are some of the questions I want all students asking themselves:
What is your abstraction?
What is an example of how your abstraction is supposed to behave? Can you show me another example?
Are there any examples of where you abstraction is allowed to fail? How should it fail on that example?
Have you tested these examples?
What is the representation of your abstraction?
How does the representation relate to the abstraction? Can you show me a picture? Can you show me in math?
What functions are allowed to see the representation? What is the contract of each function? Does the representation satisfy an invariant that the function can assume? Does each function make sure the invariant is preserved?
What does valgrind say?
One of the most common problems in teaching is determining whether the student understood you. An easy and effective way to determine if you should continue or rephrase is to have the student demonstrate their understanding by doing something closely related but not identical.
Also, since programming is essentially word problems, it's important that the student break things down into steps. I'd be asking to see their highlevel step-through before I showed them anything. Too many people get hung up in syntax and never really nail down what they're trying to do before diving in.
A general experience in explaining stuff to others is to find out where they stand first. Try to refrain from giving them solutions to problems they don't even have yet (even if you are sure that they will come across them later). In other words, don't go two steps ahead of them. If they have problems understanding call-by-value, don't explain them recursion.
As far as helping fellow students in general, I generally use the "play stupid" approach. I pretend that I know nothing about their particular assignment, and I ask them to get me up to speed on what they are supposed to be doing. I also ask them to give me a quick run-down of what they learned in class about whatever concept the assignment is about. This usually takes about 5 minutes and about 95% of the time, the other student has answered their own question by the time they finish explaining it to me. If they haven't solved it by this point, I ask them to walk me through their solution to the assignment. In doing this, they usually catch where their solution deviates from what they just said they learned in class.
As far as programming-specific help goes, I sometimes ask the other student to send me their code and I run it through a simple shell script I wrote. That script blanks out everything in the code file that is not a comment, and I give the result to the other student to read. The resulting file usually reads like an outline of their code, and a lot of times they can see where their code went wrong simply by getting the code out of the way. If their approach is completely wrong, I tell them to write an outline of what the code is supposed to do (in high-level terms) using comments; after completing this, they fill in each section of the outline with code that implements that outline step (testing each "chunk" as they go). This helps a lot of people separate the code from the algorithm (many common problems I see stem from the lack of a systematic or disciplined approach to problem solving, and this exercise helps get them on the right path).
Another method is to answer questions using a different programming language. For example, I helped several of my fellow students on Matlab projects by explaining the concepts using C, Ruby, or even pseudo-code (that read more like plain English than code). I knew that they had far more experience with other languages, so I used what they knew best to illustrate the concepts and encouraged them to try solving the problem in their "native language" first. Once they were confident that they understood the concepts, they could work on figuring out how to implement them in the target language. Having to learn new concepts while you are still learning a language makes both more difficult. This approach also helps determine whether they are having trouble understanding how to solve the problem or how to code the solution.
PSYCHOLOGICAL APPROACH
show them some popular real world APPLICATIONS (as an example) which they use day to day...written in same programming language you are trying to teach.....
explain every thing with background
give every student, considerable importance
alwaysss use colour coded syntax

What direction should I take to improve my programming skills? [closed]

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I've been attempting to learn programming (in C#) for a few years now. The problem I've had is that I'd know what I want to do (or what I want the program to do), but no idea on how to actually implement it. So I often wonder what it is I'm lacking. Is the mindset of a programmer somehow different, and I've yet to condition myself to that type of thinking, or do I just need to know more about syntax and what they do?
Of course, it's compounded by the fact that I have no means of taking classes at the moment.
So is trial and error the way to being a better programmer, or are there essential pieces that I presently lack?
Also, my goal is to eventually get into the Gaming Industry, and I don't know if that affects anything at this point.
By far the best way to improve your skills is to practice, practice, practice, and then practice some more. Just like an athlete gets better and hones his skills and natural abilities, the more you code the better you will get. Your best resources are going to be books and the internet--blogs, articles, websites such as SO are incredible sources of information. Google is your friend, learn how to use it effectively.
Find a problem you want to solve, and then find two or three ways to solve it. Being able to approach a problem from different angles can be an invaluable skill.
I would also recommend finding an open source project you can participate in. There are plenty of 'em out there.
Yeah, it's pretty much trial and error.
Or more accurately, research, trial, error, cry, fix, error, research, success!
Anything I want to do (that is new) I typically find by doing various searches, or I accidentally learn by participating in forums like this, and then am lucky enough to remember when it becomes neccessary.
Just dedicate yourself to research and trying "various things", and then you'll become better at it. You just need to accept that it will be difficult at first, and that that is quite acceptable and appropriate.
You'll get the hang of it. As long as you're motivated, you'll achieve what you wish.
I think the most valuable thing at this point is seeing working code in action. Get your hands on lots of working sample apps with full source that interest you. Look at the source, figure out what does what, and start to modify it!
Then try to write your own apps using similar constructs, and you'll find it much easier.
I like silky's second sentence. I agree. Just hang in there.
Find a project (small project) that you want to do, and then learn how to do it. Any project...like build a calculator or something. If you have a goal in mind, it makes it a lot easier...and it will make it easier to people to help you when you post questions so they can have a frame of reference.
Lots of google searches...and stackoverflow searches ;)
One other way that can get you started is to look at standard examples (and I'm sure you can find lots of those for C#) try and run them, understand what they do, and then start modifying them and play around.
Get your questions from such tinkering answered by reseaching the net etc.
Increase complexity and you'd be on your way in a while.
Search around for an C# Open Source project that interests you. Most projects will take any help you can give. This will allow you to practice your skills in a controlled environment.
You do have means to take courses at the moment. There are entire courses, complete with free textbooks, available online. And that's just one quick example.
I recommend you work your way through a couple of coding and design books while learning the syntax of a language or 2. Code Complete is a great place to start. As far as what you should start programming, aim for simple things that will solve a problem you have. While picking up a language I have done things like write a program that will auto-organize my media library, kick off processes based on things I tweet from my cell phone, quickly add shortcuts to my favorite launcher app, or organize and archive all of my saved school work at the end of a semester. Also, look at a LOT of other people's code. It's can be hard to code better until you've looked at better code.
With this approach you'll build your abstract skills like design and upfront preparation, practical skills like file access and network communication, and general programmer toolbox items like regular expressions and reflection.
Another interesting thing to try is Code Kata. How do you become a great musician or learn to ski or speak a foreign language? Practice. Practice. Practice.
Google for Bruce Eckel's "Thinking in ..." books, they're free and very good
Take a look at functional programming languages - This will broaden your mind and therefore change (and probably enhance) the way you look at code and problems.

Comments & OpenSource software [closed]

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This may sound like a foolish question or an observation, but i have seen that most of the times when one tries to look at the opensource code, there are no comments or just one or two lines at the start of the function telling what the function is used for e.g. register a user or data in table etc. There is no code which actually explains what exactly the function is doing etc.
Is it done intentionally (removal of comments) when a code is released to open source community to make things difficult to understand by others?
There is a line of thought that says that comments are unnecessary when the code speaks for itself. I don't believe comments would be removed on purpose, though.
I've seen both sides, and frankly code in general is insufficiently documented.
I've been congratulated and thanked for leaving copious breadcrumbs but that's because I've had to sift through too much undocumented code to want to subject anyone else to it.
Call it an ethical obligation.
My reason to document code: my short-term memory is junk. I write comments to remind myself of why I did something. Everyone else benefiting from that is gravy.
I don't think there is a practice or policy to remove comments when releasing software as Open Source. A sneaky software publisher might think that a good idea (maintaining de facto exclusivity, because nobody can't understand it, while having released an open source product) but this would cripple the Open Source project from the start and most likely render it unusable.
The code you are talking about is probably just very little documented. As ocdecio says, that can be either a good sign (the code speaks for itself and does not need comments) or a bad one (it is badly documented, bad code). Both cases are entirely possible. :)
What are you comparing it to?
I doubt that closed-source code has better comments.
As for what functions do, there is probably API documentation. No need to duplicate those in comments.
As a rule, functions should be small enough and written in a way that allows working out how it works by just reading them. A comment on top of the function describing what it does helps getting a quick overview of the function itself when reading through the whole source code file (unless the function name speaks for itself).
Many projects are organized in that way, and that is great.
However, what I am often missing when trying find my way around a larger codebase is something describing the big picture, i.e. the general architecture, principles, what goes where and similar things.
All open source is not made the same. This is what we call a generalization.
If you look at the website Ohloh, which tracks a very large amount of the open source software in existence, it paints a much different picture:
http://www.ohloh.net/languages?query=&sort=code
For instance, in the C language, there are 252+ million lines of comments, approx 1 in every 5 lines of C is a comment. For Java, nearly 1 in 3 lines is a comment. That's not bad.
Open source software has bad comments and bad documentation most of the time. There are various reasons why, some better than others. Usually they relate to laziness or the developers 'being in the moment'. None of the reasons are good reasons.

Are comments necessary for a programming language? [closed]

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After some stupid musings about Klingon languages, that came from this post I began a silly hobby project creating a Klingon programming language that compiles to Lua byte-code. During the initial language design phase I looked up information about Klingon programmers, and found out about this Klingon programming rule:
A TRUE Klingon Warrior does not comment his code!
So I decided my language would not support commenting, as any good Klingon would never use them.
Now many of the Klingon ways don't seem reasonable to us Human programmers, however while dabbling with the design and implementation of my hobby language I came to realize that this Klingon rule about commenting is indeed very reasonable, if not great.
Removing the ability to comment from a programming language meant I HAVE to write literate code, no exceptions.
So it got me wondering if there are any languages out there that don't support comments?
Is there are any really good arguments to not remove commenting from a language?
Edit: Any good examples of comments required?
P.S.> My hobby language above is partially silly anyways, so don't focus too much on my implementation, as much as the concept of comments required in general
Do not comment WHAT you are doing, but WHY you are doing it.
The WHAT is taken care of by clean, readable and simple code with proper choice of variable names to support it. Comments show a higher level structure to the code that can't be (or is hard to) show by the code itself.
I am not sure I agree with the "Have" in the statement "Removing the ability to comment from a programming language meant I HAVE to write literate code, no exceptions", since it is not as if all code is documented. My guess is that most people would write unreadable code.
More to the point, I personally do not believe in the reality of the self-explanatory program or API in the practical world.
My experience from manually analyzing the documentation of entire APIs for my dissertation suggests that all too often you would have to carry more information than you could convey in the signature alone. If you eliminate interface comments from your language, what are the alternatives? No documentation is not an option. External documentation is less likely to be read.
As for internal documentation, I can see your point in wanting to reduce documentation to convince people to write better. However, comments serve many collaboration and coordination purposes and are meant to raise awareness of things. By banishing these details to extenral locations, you are reducing the chances that they come to a future reader's awareness, unless your tooling is great.
Ugh, not being able to quickly comment out a line (or lines) during testing sounds annoying to me, especially when scripting.
In general comments are a wart that indicates poor design, especially long rambling comments where its clear the developer didn't have a clue what the heck they where doing and tried to make up for it by writing a comment.
Places where comments are useful:
Leaving a ticket number next to a fix so future programmers can understand business requirements
Explaining a particularly tricky hack
Commentary on business logic for a piece of code
Terse descriptions in API docs so a third-party can use your API
In all circumstances programmers should endeavor to write code that is descriptive and NOT write comments that describe poorly written code. That being said I think there are plenty of valid reasons that languages should and must support comments.
Your code has two distinct audiences:
The compiler
Human beings like us
If you choose to remove comments altogether, the assumption you are taking is that you will be catering only to the compiler, and to nothing else.
Of course you, being Klingon, may not need comments because you are not human. Perhaps you could clearly demonstrate to us your ability by speaking in IL instead?
You don't need a single assertion in your code because, in release mode, they're all gone. But when C++ didn't have assertions built-in, someone wrote the assert macro to replace it.
Of course you don't need comments, either, for more or less the same reason. But if you design a language without comments, people will start doing things like:
HelperFunctionDoesNothing("This is a comment! Blah Blah Blah...");
I'm curious. How do you stop someone from declaring a static string containing a comment and then ignoring the variable for the rest of the func/method/procedure/battle/whatever?
var useless_comment = "Can we destroy our enemies?"
if (phasers on full) return Qapla'
Languages need comments. At least 95% of comments can be replaced by clearer code but there are still assumptions you need to document and you absolutely need to document if there's some external problem you are working around.
I never write a comment without first considering if I can change the code to eliminate the need for it but sometimes you can't.
While all source code is copyrighted by default. It is often nice to:
remind the person reading the source code that it is subject to copyright
tell people what the licensing terms are for that source code file
tell them whether or not they are looking at a protected trade secret
Unfortunately, without comments, it is difficult to do this.
Am I the only one who comments out a couple of lines code for a number of purposes?
It's going to be harder than you think to make a language where comments are impossible.
if (false) {
print("This is a comment. Chew on that, Klingons!")
}
While it's true that humans need to be able to comment code, it is not absolutely necessary that the language directly support commenting: for most languages, it would be trivial to write a script that deletes one line comments (for example, all lines beginning with '#' or some other character) then runs the compiler.
Actually, though, I am surprised and disappointed to learn that even my favorite esoteric programming languages support comments: Brainf**k and Whitespace. These languages are meant to be hard to read, so it seems like they shouldn't support commenting. (As opposed to my other favorite esoteric language: LOLCode, which is meant to be self-documenting, in lolcats-speech)
I would dissent from the other answerers on this point: I say, be true to your vision of a Klingon programming language, and do not support comments!
A point against comments is that they tend to often fall out of date with the code. Any time you add a redundancy, you're risking this sort of inconsistency.
There's actually some interesting research that I've seen when a group used NLP to analyze locking comments in some large system and then compare them to the results of static analysis and were able to fix a few bugs that way.
Isn't literate programming as much comment as it is code? Certainly, much of what I've seen of literate programming has as much explanation as code, if not more comment.
You might think that developers writing in your language will make an extra effort to write clear code but the onus will actually be on you to design a language that's so expressive that it doesn't need to be commented. Hell, not even English is like that (we still parenthesize!). If your language isn't so designed it may very well be as usable as Brainfuck and enjoy the popularity and respect of Brainfuck.
Should I add links or are links considered commentlike?
Besides, people will find ways to add comments if they need to by highjacking strings and misusing variable names (that do nothing other than stand in for comments). Have you read Godel Escher Bach?
It will be a bad idea to remove the commenting facility altogether. Surely developers must learn to write code with minimum comments i.e. to write self documenting code but there a lot of cases where one has to explain why something is being done the way it is. Consider the following cases:
a new developer might start maintaining the code and the original dev has left/ out of the project
a change in specification or market requirement leads to something that is counter intuitive
copy right notice especially if open source (some open source libs require you to do this)
It is also my experience that new programmers tend to comment more and as they develop expertise their code tends to become self documenting and concise. In general comments should be about WHY and not HOW or WHAT.
NO -- there is not a single programming language out there that requires comments.
The language is for the computer. The comments are for the humans. You can write a program with 0% comments. It'll execute, rightly or wrongly. You can't write a program with 100% comments. It'll either not compile -- no main(), etc. -- or, for scripting languages, do exactly nothing.
And, besides, real programmers don't comment their code. Just like Klingons.
While I agree with Uri's responses, I too have made a language with no comments. (ichbins.) The language was to be as simple as possible while still being able to express its own compiler cleanly; since you can do that without comments, they got jettisoned.
I'm working off and on on a revision that does support commentary, but a bit differently: literate-programming style with code nested in text instead of comments embedded in code. It might also get examples/test-cases later as a first-class language feature.
Good luck with the Klingon hacking. :-)
I can't tell you how thankful I am for Javadoc - which is really simple to set up within comments. So that's at least one sense in which comments are useful.
No, of course a language doesn't have to have commenting. But a (useful) program does have to have comments... I don't agree with your idea that literate code lacks comments. Some very good code is easily comprehensible with comments, but only with difficulty without.
I think the comments are required in many situations.
For instance, think of the algorithmic ones. Suppose there is a function written in C which solves the Traveling Salesperson Problem, there are wide range of techniques that can be used to deal with this problem. And the codes are usually cryptic by its nature.
Without explicitly describing the parameters and the algorithm used, by using comments, it is almost impossible to reuse this piece of code.
Can we live without comments on code? Sure, but that won't make live easier.
Comments are useful because they reassure the person reading your code - probably the "future you" - that you've thought about her welfare.
I think the question may become how self-contained would the language without comments be? If for example, it compiles down to DLLs that get used within other code, then how does one know anything beyond the function signature in terms of what it requires, changes and returns? I wouldn't want to have function names being dozens of characters to try to express what may be very easily done with comments above the function that can be used as documentation within something like the Object Browser within Visual Studio for example.
Of course!!
The main reason is novice developers. Not everyone knows how to write literate code. Actually there are millions out there don't get a NullPointerException when they see one.
We all start at some point.
But if you're targeting to "expert" developers only, why bother in the language in first place. You should be using butterflies !!! That's what real developer use!
Comments is a must, try to make it harder if you wish ( like using #//##/ sequence to create a comment or something like that ) but don't leave it out.
:)
I agree with you that nicely written code does not need any comments as "Code is only good documentation available to programmer. However this is very ideal condition, not everyone writes good code all time.
So to make poorly written code good in future comments are required.
I once wrote a VB app (a silly board game inspired by Monopoly) without any comments. But I did that just to piss off my teacher, who had told us comments were for "whatever we found relevant, so we could remember it later".
Perfect code needs zero comments. It should be simple, and understandible by complete novices.
Any code needs comments, I try to explain the reason for and workings of every function I write in 1 or 2 lines.
Code that explains itself only exists in a perfect world, there is always some weird hack or a reason to do something quick-n-dirty instead of the propper way.
The best thing to remember is to comment WHY code does what it does, good code explains WHAT it does 99% of the time.
Write something simple, like a piece of code that can solve a Sudoku puzzle (3 reasonably simple while loops) and try reading that 3 months later. You will immidiatly find something that isn't exactly clear.
Code is written once, but read many times over the course of its lifetime; thus it pays to optimize for readability. Clear and consistent naming of everything from constants to classes is necessary, but may or may not be sufficient to achieve this objective. If not, fill in the gaps with comments, and maintain them as you would the code.