Can we change the way Rails writes HTML IDs and such? - html

I just started checking out Wordpress' CSS Architecture to study a system that's established and pretty powerful to learn better HTML habits. I've noticed they use all hyphens - (post-554 for example), while Rails uses underscores _ (post_554 for example). I'm wondering if there's some setting to customize this in Rails, something like ActionView::Template.word_boundary = "-".
Is there? Not that it really matters, just trying to learn why people do things the way they do.
:)

You can't change se separator. It is hard-coded into Rails.
For example, post_554 is generated by the dom_id helper, which internally relies on the RecordIdentifier class.
Here's the definition.
def dom_id(record, prefix = nil)
if record_id = record.id
"#{dom_class(record, prefix)}#{JOIN}#{record_id}"
else
dom_class(record, prefix || NEW)
end
end
The separator, the JOIN constant, is defined as freezed String so you can't change it.
module RecordIdentifier
extend self
JOIN = '_'.freeze
NEW = 'new'.freeze
There are two ways to change it:
Create your own helper (suggested)
Overwrite the existing methods/helpers with your own implementations (not suggested)
There are also some technical restrictions that explain the reason behind this choice, mainly tied to the language behind Rails.
For instance, talking about symbols
:post_554 # valid symbol
:post-554 # invalid symbol
:"post-554" # valid symbol
Using - would probably require a less cleaner approach to Ruby.
Personally, I prefer using - rather than _ and I tend to avoid standard Rails helpers unless strictly required.

Related

Having Multiple Commands for Calling a Specific Programming Language: To Provide a Delimiter-less Option or Not?

After re-reading the off/on topic lists, I'm still not certain if this question is best posted to this site, so apologies in advance, if it is not.
Overview:
I am working on a project that mixes several programming languages and we are trying to determine important considerations for the command used to call one in particular.
For definiteness, I will list the specific languages; however, I think the principles ought to be general, so familiarity with these specific languages is not really essential.
Specific Context
Specifically, we are using: Maxima, KaTeX, Markdown and HTML). While building the prototype, we have used the following (I believe, standard) conventions:
KaTeX delimited by $ $ or $$ $$;
HTML delimited by < > </ > pairs;
Markdown works anywhere in the body, except within KaTeX or Maxima environments;
The only non-standard convention we used during this design phase was to call on Maxima using \comp{<Maxima commands>}. This command works within all the other environments (which is desired).
Now that we are ready to start using the platform, it has become apparent that this temporary command for calling Maxima is cumbersome for our users. The vast majority of use cases involve simply calling a single variable or function, e.g.
As such, we have $\eval{function-name()}(\eval{variable-name})$
as opposed to actually using Maxima for computation, e.g.
Here, it is clear that $\eval{a} + \eval{b} = \eval{a+b}$
(where \eval{a+b} would return the actual sum, as calculated by Maxima).
As such, our users would prefer a delimiter-less command option for invoking a single variable or function, e.g. \#<variable-name-in-Maxima> and \#<function-name>(<argument>) (where # is some reserved character not used in the other languages), while also having a delimited alternative for the (much less frequent) cases where they actually want to use Maxima for computation; perhaps something like \#{a+b}.
However, we have a general sense that this is not a best practice, even though we can't foresee any specific issue.
"Research" / Comparisons:
Indeed, there is precedence for delimit-less expressions for single arguments like x^2 (on any calculator) or Knuth's a \over b in TeX (which persists in LaTeX with \frac12 being parsed as \frac{1}{2}.
IIRC Knuth's point was that this delimit-less notation was more semantic (and so, in his view, preferable), and because delimiters can be added, ambiguity can be avoided, whenever the need arises: e.g. x^{22}, {a+b}\over{c+d} and \frac{12}{3}.
The Question, Proper:
Can anyone point to or explain actual shortcomings / risks associated with a dual solution like:
\#<var>, \#<function>(<arg>) and,
\#[<extended expression>],
(where # is a reserved (& escapable) character), for calling one language amongst others, as opposed to only using a delimited command?
Any alternative suggestions for how to achieve the ease-of-use and more semantic code enabled by the above solution, while keeping the code unambiguous would be very much welcome and appreciated.

Avoiding Language Keyword Conflicts

How do you guys avoid keyword conflicts in your language?
For example, I'm creating a class (VB 2008) to hold all the configuration variables for some reports we generate. Naturally, one of the variables is "Date". And of course you can't have anything named the same as a keyword. In VB 2008 you do have the option of surrounding a conflicting word with []'s and fix it but I've always seen that as a hack. Any suggestions? What are your names to get around common keywords?
Code to help visualize...
Dim m_Title As String
Dim m_Date As String
Public Property Title() As String
Get
Return m_Title
End Get
Set(ByVal value As String)
m_Title = value
End Set
End Property
Public Property [Date]() As String
Get
End Get
Set(ByVal value As String)
End Set
End Property
Probably think about more specific nature of the variable?
From your example, the "Date" can be "Created Date" or "Posted Date" or anything else. If you find your variable names too trivial, you may be oversimplifying (or even obfuscating) your code. Help your coworkers by creating a clear but concise variable names.
Don't look at [Date] as a hack; if your property represents a date, it should be called Date. Use the tools you have available to get the job done. Personally I feel that properties that have the names they do only to get around such conflicts are more of a hack, since you will get to deal with it every time you use the property.
misspell your variable names!
On .NET, it is reasonable to consider the Common Language Specification (CLS) as the lowest common denominator that you should cater to. This is documented in ECMA-335 "Common Language
Infrastructure (CLI) Partitions I to VI". Here's what it says specifically about names; a note in CLS Rule #4 (8.5.1 "Valid names"):
CLS (consumer): Need not consume types that violate CLS Rule 4, but shall have a mechanism to allow access to named items that use one of its own keywords as the name.
So no, it's not really a hack, but a definite rule. The reason why it's there is that, as .NET is extensible as far as languages targeting it go, you can never avoid name clashes. If you cover C#, there's VB. If you cover C# and VB, there's C++/CLI. If you cover all those, there's F# and Delphi Prism. And so on. Hence why it is mandated by CLS that languages provide a way to escape their keywords as identifiers; and all languages I've listed provide some way to do so (and thus are compliant CLS consumers).
In general, it is still considered good manners to avoid clashes with either C# or VB non-context keywords, mainly because those two languages are the most popular by a very large margin. For example, it is the reason why it's HashSet and not just Set - the latter is a VB keyword. The full listings are:
C# keywords
VB keywords
Most languages have something to escape any reserved words. C# has # so you can use #class as an argument name (something MVC adopters are learning).
If the domain states that a certain word be used to describe it then that is what the escaping of reserved words is there for. I wouldn't be afraid to escape reserved words to get my model close to the domain even if it means more typing - the clarity is worth it!
To avoid naming conflicts with keywords, I simply don't use keywords.
In your case, Date. Date of what? If I had to maintain your application that would probably be the first thing I'd ask. The great thing about keywords is that they're completely generic, something a variable name should never be.
There is no silver bullet, but modern languages help a lot with better abilities to manage namespaces.
In my case, I curse the fact that C has an 'index' command.
"Date_" or "_Date".
This is one question where Perl dodges the question entirely.
Variables always have one of $%#*&, the only things that can conflict are Globs/Handles, and subroutines.
Even that isn't much of a problem because Globs/Handles aren't used very much any more.
Subroutines and keywords are very much the same in Perl. If you need to get at the built-in subroutine/keyword you can get at it by appending CORE::, for example CORE::dump.
Really I think the only keywords you would have a problem with are sub, my, local, and 'our', because those keywords are parsed very early in parser. Note that you can still create a sub with those names, it just won't work without specifying the full name, or from a blessed reference, or with a symbolic reference.
{
package test;
sub my{ print "'my' called using $_[-1]\n" };
sub new{ bless {}, $_[0] };
sub sub{ print "'sub' called using $_[-1]\n" };
sub symbolic{
*{__PACKAGE__.'::'.$_[1]}{CODE}->('symbolic reference');
}
my $var; # notice this doesn't call test::my()
}
package main;
my $test = test->new;
# Called from a blessed reference
$test->my('blessed reference');
$test->sub('blessed reference');
print "\n";
# Called using the full name
test::my('full name');
test::sub('full name');
print "\n";
# Called using a symbolic reference
$test->symbolic('my');
$test->symbolic('sub');
Output:
'my' called using blessed reference
'sub' called using blessed reference
'my' called using full name
'sub' called using full name
'my' called using symbolic reference
'sub' called using symbolic reference

Using magic strings or constants in processing punctuation?

We do a lot of lexical processing with arbitrary strings which include arbitrary punctuation. I am divided as to whether to use magic characters/strings or symbolic constants.
The examples should be read as language-independent although most are Java.
There are clear examples where punctuation has a semantic role and should be identified as a constant:
File.separator not "/" or "\\"; // a no-brainer as it is OS-dependent
and I write XML_PREFIX_SEPARATOR = ":";
However let's say I need to replace all examples of "" with an empty string ``. I can write:
s = s.replaceAll("\"\"", "");
or
s = s.replaceAll(S_QUOT+S_QUOT, S_EMPTY);
(I have defined all common punctuation as S_FOO (string) and C_FOO (char))
In favour of magic strings/characters:
It's shorter
It's natural to read (sometimes)
The named constants may not be familiar (C_APOS vs '\'')
In favour of constants
It's harder to make typos (e.g. contrast "''" + '"' with S_APOS+S_APOS + C_QUOT)
It removes escaping problems Should a regex be "\\s+" or "\s+" or "\\\\s+"?
It's easy to search the code for punctuation
(There is a limit to this - I would not write regexes this way even though regex syntax is one of the most cognitively dysfunctional parts of all programming. I think we need a better syntax.)
If the definitions may change over time or between installations, I tend to put these things in a config file, and pick up the information at startup or on-demand (depending on the situation). Then provide a static class with read-only interface and clear names on the properties for exposing the information to the system.
Usage could look like this:
s = s.replaceAll(CharConfig.Quotation + CharConfig.Quotation, CharConfig.EmtpyString);
For general string processing, I wouldn't use special symbols. A space is always going to be a space, and it's just more natural to read (and write!):
s.replace("String", " ");
Than:
s.replace("String", S_SPACE);
I would take special care to use things like "\t" to represent tabs, for example, since they can't easily be distinguished from spaces in a string.
As for things like XML_PREFIX_SEPARATOR or FILE_SEPARATOR, you should probably never have to deal with constants like that, since you should use a library to do the work for you. For example, you shouldn't be hand-writing: dir + FILE_SEPARATOR + filename, but rather be calling: file_system_library.join(dir, filename) (or whatever equivalent you're using).
This way, you'll not only have an answer for things like the constants, you'll actually get much better handling of various edge cases which you probably aren't thinking about right now

What is your system for avoiding keyword naming clashes?

Typically languages have keywords that you are unable to use directly with the exact same spelling and case for naming things (variables,functions,classes ...) in your program. Yet sometimes a keyword is the only natural choice for naming something. What is your system for avoiding/getting around this clash in your chosen technology?
I just avoid the name, usually. Either find a different name or change it slightly - e.g. clazz instead of class in C# or Java. In C# you can use the # prefix, but it's horrible:
int #int = 5; // Ick!
There is nothing intrinsically all-encompassing about a keyword, in that it should stop you from being able to name your variables. Since all names are just generalized instances of some type to one degree or another, you can always go up or down in the abstraction to find another useful name.
For example, if your writing a system that tracks students and you want an object to represent their study in a specific field, i.e. they've taken a "class" in something, if you can't use the term directly, or the plural "classes", or an alternative like "studies", you might find a more "instanced" variation: studentClass, currentClass, etc. or a higher perspective: "courses", "courseClass" or a specfic type attribute: dailyClass, nightClass, etc.
Lots of options, you should just prefer the simplest and most obvious one, that's all.
I always like to listen to the users talk, because the scope of their language helps define the scope of the problem, often if you listen long enough you'll find they have many multiple terms for the same underlying things (with only subtle differences). They usually have the answer ...
Paul.
My system is don't use keywords period!
If I have a function/variable/class and it only seems logical to name it with a keyword, I'll use a descriptive word in front of the keyword.
(adjectiveNoun) format. ie: personName instead of Name where "Name" is a keyword.
I just use a more descriptive name. For instance, 'id' becomes identifier, 'string' becomes 'descriptionString,' and so on.
In Python I usually use proper namespacing on my modules to avoid name clashes.
import re
re.compile()
instead of:
from re import *
compile()
Sometimes, when I can't avoid keyword name clashes I simply drop the last letter off the name of my variable.
for fil in files:
pass
As stated before either change class to clazz in Java/C#, or use some underscore as a prefix, for example
int _int = 0;
There should be no reason to use keywords as variable names. Either use a more detailed word or use a thesaraus. Capitalizing certain letters of the word to make it not exactly like the keyword is not going to help much to someone inheriting your code later.
Happy those with a language without ANY keywords...
But joke apart, I think in the seldom situations where "Yet sometimes a keyword is the only natural choice for naming something." you can get along by prefixing it with "my", "do", "_" or similar.
I honestly can't really think of many such instances where the keyword alone makes a good name ("int", "for" and "if" are definitely bad anyway). The only few in the C-language family which might make sense are "continue" (make it "doContinue"), "break" (how about "breakWhenEOFIsreached" or similar ?) and the already mentioned "class" (how about "classOfThingy" ?).
In other words: make the names more reasonable.
And always remember: code is WRITTEN only once, but usualy READ very often.
Typically I follow Hungarian Notation. So if, for whatever reason, I wanted to use 'End' as a variable of type integer I would declare it as 'iEnd'. A string would be 'strEnd', etc. This usually gives me some room as far as variables go.
If I'm working on a particular personal project that other people will only ever look at to see what I did, for example, when making an add-on to a game using the UnrealEngine, I might use my initials somewhere in the name. 'DS_iEnd' perhaps.
I write my own [vim] syntax highlighters for each language, and I give all keywords an obvious colour so that I notice them when I'm coding. Languages like PHP and Perl use $ for variables, making it a non-issue.
Developing in Ruby on Rails I sometime look up this list of reserved words.
In 15 years of programming, I've rarely had this problem.
One place I can immediately think of, is perhaps a css class, and in that case, I'd use a more descriptive name. So instead of 'class', I might use 'targetClass' or something similar.
In python the generally accepted method is to append an '_'
class -> class_
or -> or_
and -> and_
you can see this exemplified in the operator module.
I switched to a language which doesn't restrict identifier names at all.
First of all, most code conventions prevent such a thing from happening.
If not, I usually add a descriptive prose prefix or suffix:
the_class or theClass infix_or (prefix_or(class_param, in_class) , a_class) or_postfix
A practice, that is usually in keeping with every code style advice you can find ("long names don't kill", "Longer variable names don't take up more space in memory, I promise.")
Generally, if you think the keyword is the best description, a slightly worse one would be better.
Note that, by the very premise of your question you introduce ambiguity, which is bad for the reader, be it a compiler or human. Even if it is a custom to use class, clazz or klass and even if that custom is not so custom that it is a custom: it takes a word word, precisely descriptive as word may be, and distorts it, effectively shooting w0rd's precision in the "wrd". Somebody used to another w_Rd convention or language might have a few harsh wordz for your wolds.
Most of us have more to say about things than "Flower", "House" or "Car", so there's usually more to say about typeNames, decoratees, class_params, BaseClasses and typeReferences.
This is where my personal code obfuscation tolerance ends:
Never(!!!) rely on scoping or arcane syntax rules to prevent name clashes with "key words". (Don't know any compiler that would allow that, but, these days, you never know...).
Try that and someone will w**d you in the wörd so __rd, Word will look like TeX to you!
My system in Java is to capitalize the second letter of the word, so for example:
int dEfault;
boolean tRansient;
Class cLass;

How to name variables

What rules do you use to name your variables?
Where are single letter vars allowed?
How much info do you put in the name?
How about for example code?
What are your preferred meaningless variable names? (after foo & bar)
Why are they spelled "foo" and "bar" rather than FUBAR
function startEditing(){
if (user.canEdit(currentDocument)){
editorControl.setEditMode(true);
setButtonDown(btnStartEditing);
}
}
Should read like a narrative work.
One rule I always follow is this: if a variable encodes a value that is in some particular units, then those units have to be part of the variable name. Example:
int postalCodeDistanceMiles;
decimal reactorCoreTemperatureKelvin;
decimal altitudeMsl;
int userExperienceWongBakerPainScale
I will NOT be responsible for crashing any Mars landers (or the equivalent failure in my boring CRUD business applications).
Well it all depends on the language you are developing in. As I am currently using C# I tend you use the following.
camelCase for variables.
camelCase for parameters.
PascalCase for properties.
m_PascalCase for member variables.
Where are single letter vars allows?
I tend to do this in for loops but feel a bit guilty whenever I do so. But with foreach and lambda expressions for loops are not really that common now.
How much info do you put in the name?
If the code is a bit difficult to understand write a comment. Don't turn a variable name into a comment, i.e .
int theTotalAccountValueIsStoredHere
is not required.
what are your preferred meaningless variable names? (after foo & bar)
i or x. foo and bar are a bit too university text book example for me.
why are they spelled "foo" and "bar" rather than FUBAR?
Tradition
These are all C# conventions.
Variable-name casing
Case indicates scope. Pascal-cased variables are fields of the owning class. Camel-cased variables are local to the current method.
I have only one prefix-character convention. Backing fields for class properties are Pascal-cased and prefixed with an underscore:
private int _Foo;
public int Foo { get { return _Foo; } set { _Foo = value; } }
There's some C# variable-naming convention I've seen out there - I'm pretty sure it was a Microsoft document - that inveighs against using an underscore prefix. That seems crazy to me. If I look in my code and see something like
_Foo = GetResult();
the very first thing that I ask myself is, "Did I have a good reason not to use a property accessor to update that field?" The answer is often "Yes, and you'd better know what that is before you start monkeying around with this code."
Single-letter (and short) variable names
While I tend to agree with the dictum that variable names should be meaningful, in practice there are lots of circumstances under which making their names meaningful adds nothing to the code's readability or maintainability.
Loop iterators and array indices are the obvious places to use short and arbitrary variable names. Less obvious, but no less appropriate in my book, are nonce usages, e.g.:
XmlWriterSettings xws = new XmlWriterSettings();
xws.Indent = true;
XmlWriter xw = XmlWriter.Create(outputStream, xws);
That's from C# 2.0 code; if I wrote it today, of course, I wouldn't need the nonce variable:
XmlWriter xw = XmlWriter.Create(
outputStream,
new XmlWriterSettings() { Indent=true; });
But there are still plenty of places in C# code where I have to create an object that you're just going to pass elsewhere and then throw away.
A lot of developers would use a name like xwsTemp in those circumstances. I find that the Temp suffix is redundant. The fact that I named the variable xws in its declaration (and I'm only using it within visual range of that declaration; that's important) tells me that it's a temporary variable.
Another place I'll use short variable names is in a method that's making heavy use of a single object. Here's a piece of production code:
internal void WriteXml(XmlWriter xw)
{
if (!Active)
{
return;
}
xw.WriteStartElement(Row.Table.TableName);
xw.WriteAttributeString("ID", Row["ID"].ToString());
xw.WriteAttributeString("RowState", Row.RowState.ToString());
for (int i = 0; i < ColumnManagers.Length; i++)
{
ColumnManagers[i].Value = Row.ItemArray[i];
xw.WriteElementString(ColumnManagers[i].ColumnName, ColumnManagers[i].ToXmlString());
}
...
There's no way in the world that code would be easier to read (or safer to modify) if I gave the XmlWriter a longer name.
Oh, how do I know that xw isn't a temporary variable? Because I can't see its declaration. I only use temporary variables within 4 or 5 lines of their declaration. If I'm going to need one for more code than that, I either give it a meaningful name or refactor the code using it into a method that - hey, what a coincidence - takes the short variable as an argument.
How much info do you put in the name?
Enough.
That turns out to be something of a black art. There's plenty of information I don't have to put into the name. I know when a variable's the backing field of a property accessor, or temporary, or an argument to the current method, because my naming conventions tell me that. So my names don't.
Here's why it's not that important.
In practice, I don't need to spend much energy figuring out variable names. I put all of that cognitive effort into naming types, properties and methods. This is a much bigger deal than naming variables, because these names are very often public in scope (or at least visible throughout the namespace). Names within a namespace need to convey meaning the same way.
There's only one variable in this block of code:
RowManager r = (RowManager)sender;
// if the settings allow adding a new row, add one if the context row
// is the last sibling, and it is now active.
if (Settings.AllowAdds && r.IsLastSibling && r.Active)
{
r.ParentRowManager.AddNewChildRow(r.RecordTypeRow, false);
}
The property names almost make the comment redundant. (Almost. There's actually a reason why the property is called AllowAdds and not AllowAddingNewRows that a lot of thought went into, but it doesn't apply to this particular piece of code, which is why there's a comment.) The variable name? Who cares?
Pretty much every modern language that had wide use has its own coding standards. These are a great starting point. If all else fails, just use whatever is recommended. There are exceptions of course, but these are general guidelines. If your team prefers certain variations, as long as you agree with them, then that's fine as well.
But at the end of the day it's not necessarily what standards you use, but the fact that you have them in the first place and that they are adhered to.
I only use single character variables for loop control or very short functions.
for(int i = 0; i< endPoint; i++) {...}
int max( int a, int b) {
if (a > b)
return a;
return b;
}
The amount of information depends on the scope of the variable, the more places it could be used, the more information I want to have the name to keep track of its purpose.
When I write example code, I try to use variable names as I would in real code (although functions might get useless names like foo or bar).
See Etymology of "Foo"
What rules do you use to name your variables?
Typically, as I am a C# developer, I follow the variable naming conventions as specified by the IDesign C# Coding Standard for two reasons
1) I like it, and find it easy to read.
2) It is the default that comes with the Code Style Enforcer AddIn for Visual Studio 2005 / 2008 which I use extensively these days.
Where are single letter vars allows?
There are a few places where I will allow single letter variables. Usually these are simple loop indexers, OR mathematical concepts like X,Y,Z coordinates. Other than that, never! (Everywhere else I have used them, I have typically been bitten by them when rereading the code).
How much info do you put in the name?
Enough to know PRECISELY what the variable is being used for. As Robert Martin says:
The name of a variable, function, or
class, should answer all the big
questions. It should tell you why it
exists, what it does, and how it is
used. If a name requires a comment,
then the name does not reveal its
intent.
From Clean Code - A Handbook of Agile Software Craftsmanship
I never use meaningless variable names like foo or bar, unless, of course, the code is truly throw-away.
For loop variables, I double up the letter so that it's easier to search for the variable within the file. For example,
for (int ii=0; ii < array.length; ii++)
{
int element = array[ii];
printf("%d", element);
}
What rules do you use to name your variables? I've switched between underscore between words (load_vars), camel casing (loadVars) and no spaces (loadvars). Classes are always CamelCase, capitalized.
Where are single letter vars allows? Loops, mostly. Temporary vars in throwaway code.
How much info do you put in the name? Enough to remind me what it is while I'm coding. (Yes this can lead to problems later!)
what are your preferred meaningless variable names? (after foo & bar) temp, res, r. I actually don't use foo and bar a good amount.
What rules do you use to name your variables?
I need to be able to understand it in a year's time. Should also conform with preexisting style.
Where are single letter vars allows?
ultra-obvious things. E.g. char c; c = getc(); Loop indicies(i,j,k).
How much info do you put in the name?
Plenty and lots.
how about for example code?
Same as above.
what are your preferred meaningless variable names? (after foo & bar)
I don't like having meaningless variable names. If a variable doesn't mean anything, why is it in my code?
why are they spelled "foo" and "bar" rather than FUBAR
Tradition.
The rules I adhere to are;
Does the name fully and accurately describe what the variable represents?
Does the name refer to the real-world problem rather than the programming language solution?
Is the name long enough that you don't have to puzzle it out?
Are computed value qualifiers, if any, at the end of the name?
Are they specifically instantiated only at the point once required?
What rules do you use to name your variables?
camelCase for all important variables, CamelCase for all classes
Where are single letter vars allows?
In loop constructs and in mathematical funktions where the single letter var name is consistent with the mathematical definition.
How much info do you put in the name?
You should be able to read the code like a book. Function names should tell you what the function does (scalarProd(), addCustomer(), etc)
How about for example code?
what are your preferred meaningless variable names? (after foo & bar)
temp, tmp, input, I never really use foo and bar.
I would say try to name them as clearly as possible. Never use single letter variables and only use 'foo' and 'bar' if you're just testing something out (e.g., in interactive mode) and won't use it in production.
I like to prefix my variables with what they're going to be: str = String, int = Integer, bool = Boolean, etc.
Using a single letter is quick and easy in Loops: For i = 0 to 4...Loop
Variables are made to be a short but descriptive substitute for what you're using. If the variable is too short, you might not understand what it's for. If it's too long, you'll be typing forever for a variable that represents 5.
Foo & Bar are used for example code to show how the code works. You can use just about any different nonsensical characters to use instead. I usually just use i, x, & y.
My personal opinion of foo bar vs. fu bar is that it's too obvious and no one likes 2-character variables, 3 is much better!
In DSLs and other fluent interfaces often variable- and method-name taken together form a lexical entity. For example, I personally like the (admittedly heretic) naming pattern where the verb is put into the variable name rather than the method name. #see 6th Rule of Variable Naming
Also, I like the spartan use of $ as variable name for the main variable of a piece of code. For example, a class that pretty prints a tree structure can use $ for the StringBuffer inst var. #see This is Verbose!
Otherwise I refer to the Programmer's Phrasebook by Einar Hoest. #see http://www.nr.no/~einarwh/phrasebook/
I always use single letter variables in for loops, it's just nicer-looking and easier to read.
A lot of it depends on the language you're programming in too, I don't name variables the same in C++ as I do in Java (Java lends itself better to the excessively long variable names imo, but this could just a personal preference. Or it may have something to do with how Java built-ins are named...).
locals: fooBar;
members/types/functions FooBar
interfaces: IFooBar
As for me, single letters are only valid if the name is classic; i/j/k for only for local loop indexes, x,y,z for vector parts.
vars have names that convey meaning but are short enough to not wrap lines
foo,bar,baz. Pickle is also a favorite.
I learned not to ever use single-letter variable names back in my VB3 days. The problem is that if you want to search everywhere that a variable is used, it's kinda hard to search on a single letter!
The newer versions of Visual Studio have intelligent variable searching functions that avoid this problem, but old habits and all that. Anyway, I prefer to err on the side of ridiculous.
for (int firstStageRocketEngineIndex = 0; firstStageRocketEngineIndex < firstStageRocketEngines.Length; firstStageRocketEngineIndex++)
{
firstStageRocketEngines[firstStageRocketEngineIndex].Ignite();
Thread.Sleep(100); // Don't start them all at once. That would be bad.
}
It's pretty much unimportant how you name variables. You really don't need any rules, other than those specified by the language, or at minimum, those enforced by your compiler.
It's considered polite to pick names you think your teammates can figure out, but style rules don't really help with that as much as people think.
Since I work as a contractor, moving among different companies and projects, I prefer to avoid custom naming conventions. They make it more difficult for a new developer, or a maintenance developer, to become acquainted with (and follow) the standard being used.
So, while one can find points in them to disagree with, I look to the official Microsoft Net guidelines for a consistent set of naming conventions.
With some exceptions (Hungarian notation), I think consistent usage may be more useful than any arbitrary set of rules. That is, do it the same way every time.
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I work in MathCAD and I'm happy because MathCAD gives me increadable possibilities in naming and I use them a lot. And I can`t understand how to programm without this.
To differ one var from another I have to include a lot of information in the name,for example:
1.On the first place - that is it -N for quantity,F for force and so on
2.On the second - additional indices - for direction of force for example
3.On the third - indexation inside vector or matrix var,for convinience I put var name in {} or [] brackets to show its dimensions.
So,as conclusion my var name is like
N.dirs / Fx i.row / {F}.w.(i,j.k) / {F}.w.(k,i.j).
Sometimes I have to add name of coordinate system for vector values
{F}.{GCS}.w.(i,j.k) / {F}.{LCS}.w.(i,j.k)
And as final step I add name of the external module in BOLD at the end of external function or var like Row.MTX.f([M]) because MathCAD doesn't have help string for function.
Use variables that describes clearly what it contains. If the class is going to get big, or if it is in the public scope the variable name needs to be described more accurately. Of course good naming makes you and other people understand the code better.
for example: use "employeeNumber" insetead of just "number".
use Btn or Button in the end of the name of variables reffering to buttons, str for strings and so on.
Start variables with lower case, start classes with uppercase.
example of class "MyBigClass", example of variable "myStringVariable"
Use upper case to indicate a new word for better readability. Don't use "_", because it looks uglier and takes longer time to write.
for example: use "employeeName".
Only use single character variables in loops.
Updated
First off, naming depends on existing conventions, whether from language, framework, library, or project. (When in Rome...) Example: Use the jQuery style for jQuery plugins, use the Apple style for iOS apps. The former example requires more vigilance (since JavaScript can get messy and isn't automatically checked), while the latter example is simpler since the standard has been well-enforced and followed. YMMV depending on the leaders, the community, and especially the tools.
I will set aside all my naming habits to follow any existing conventions.
In general, I follow these principles, all of which center around programming being another form of interpersonal communication through written language.
Readability - important parts should have solid names; but these names should not be a replacement for proper documentation of intent. The test for code readability is if you can come back to it months later and still be understanding enough to not toss the entire thing upon first impression. This means avoiding abbreviation; see the case against Hungarian notation.
Writeability - common areas and boilerplate should be kept simple (esp. if there's no IDE), so code is easier and more fun to write. This is a bit inspired by Rob Pyke's style.
Maintainability - if I add the type to my name like arrItems, then it would suck if I changed that property to be an instance of a CustomSet class that extends Array. Type notes should be kept in documentation, and only if appropriate (for APIs and such).
Standard, common naming - For dumb environments (text editors): Classes should be in ProperCase, variables should be short and if needed be in snake_case and functions should be in camelCase.
For JavaScript, it's a classic case of the restraints of the language and the tools affecting naming. It helps to distinguish variables from functions through different naming, since there's no IDE to hold your hand while this and prototype and other boilerplate obscure your vision and confuse your differentiation skills. It's also not uncommon to see all the unimportant or globally-derived vars in a scope be abbreviated. The language has no import [path] as [alias];, so local vars become aliases. And then there's the slew of different whitespacing conventions. The only solution here (and anywhere, really) is proper documentation of intent (and identity).
Also, the language itself is based around function level scope and closures, so that amount of flexibility can make blocks with variables in 2+ scope levels feel very messy, so I've seen naming where _ is prepended for each level in the scope chain to the vars in that scope.
I do a lot of php in nowadays, It was not always like that though and I have learned a couple of tricks when it comes to variable naming.
//this is my string variable
$strVar = "";
//this would represent an array
$arrCards = array();
//this is for an integer
$intTotal = NULL:
//object
$objDB = new database_class();
//boolean
$blValid = true;