does any one know that
"what does '#' character means in JNDI look up?"
like:
helloUser = (HelloUser) ctx.lookup("HelloUser#ejb3inaction.example.HelloUser");
thanks a lot
It doesn't mean anything special. It's just a convenient delimiter that doesn't require escaping. Other characters could have been used. For example, "!" was chosen by the EJB 3.1 specification.
Related
I'm working on a translation project and I'm moving all of the English strings out of the views and into a YAML file. Some of the very well written strings employ special characters such as ampersands and N-dashes.
Is there any way to include those?
In the meantime I've turned "&" to "and" and "–" to "--"
but, at least in the English version, I feel like the copy starts to loose it's flavor. I doubt the Chinese version will miss these, but maybe they will want different special characters that I don't know about.
You can have special characters in YAML file values as long as they're not at the beginning of a string.
In the case of &, for example, if it is the first character of your string, then your YAML parser will think it's an anchor, when it tries to read the string (if it's not, like key: this & that, then it will be read as a string, as you would expect).
For more information about what you can and can't have in your YAML strings (and what are considered special characters), see:
YAML Ruby Cookbook
The question and accepted answer for Do I need quotes for strings in Yaml?
It seems that it is best to use the & escape, instead of simply typing the ampersand (&).
However, should we be using X/HTML character entity references for dashes and other common typographical characters when writing blog posts on CMSs like WordPress or hard-coding websites by hand?
For example:
– is an en dash (–)
— is an em dash (—)
What is the risk if we do not?
Why is the hyphen (-) never written as - but simply typed directly from the keyboard in HTML? (Assuming that it the hyphen, and not a minus sign.)
The W3C released an official response about when to use and when not to use character escapes which you can find here. As they are also the group that is in charge of the HTML specification, I think it's best to follow their advice.
From the section "When to Use Escapes"
Syntax characters. There are three characters that should always appear in content as escapes, so that they do not interact with the syntax of the markup. These are part of the language for all documents based on XML and for HTML.
< (<)
> (>)
& (&)
They also mention using characters that might not be supported in the current encoding.
From the section "When Not to Use Escapes"
It is almost always preferable to use an encoding that allows you to represent characters in their normal form, rather than using character entity references or NCRs.
Using escapes can make it difficult to read and maintain source code, and can also significantly increase file size.
http://www.w3.org/International/questions/qa-escapes
Those entities are there to help you, the author, with characters not usually typable on your average keyboard. (The em dash is an example —, as well as © and ).
You only need to escape those characters that have meaning in (X)HTML < > and &.
I am in need of matching Unicode letters, similarly to PCRE's \p{L}.
Now, since Dart's RegExp class is based on ECMAScript's, it doesn't have the concept of \p{L}, sadly.
I'm looking into perhaps constructing a big character class that matches all Unicode letters, but I'm not sure where to start.
So, I want to match letters like:
foobar
מכון ראות
But the R symbol shouldn't be matched:
BlackBerry®
Neither should any ASCII control characters or punctuation marks, etc. Essentially every letter in every language Unicode supports, whether it's å, ä, φ or ת, they should match if they are actual letters.
I know this is an old question. But RegExp now supports unicode categories (since Dart 2.4) so you can do something like this:
RegExp alpha = RegExp(r'\p{Letter}', unicode: true);
print(alpha.hasMatch("f")); // true
print(alpha.hasMatch("ת")); // true
print(alpha.hasMatch("®")); // false
I don't think that complete information about classification of Unicode characters as letters or non-letters is anywhere in the Dart libraries. You might be able to put something together that would mostly work using things in the Intl library, particularly Bidi. I'm thinking that, for example,
isLetter(oneCharacterString) => Bidi.endsWithLtr(oneLetterString) || Bidi.endsWithRTL(oneLetterString);
might do a plausible job. At least it seems to have a number of ranges for valid characters in there. Or you could put together your own RegExp based on the information in _LTR_CHARS and _RTL_CHARS. It explicitly says it's not 100% accurate, but good for most practical purposes.
Looks like you're going to have to iterate through the runes in the string and then check the integer value against a table of unicode ranges.
Golang has some code to generate these tables directly from the unicode source. See maketables.go, and some of the other files in the golang unicode package.
Or take the lazy option, and file a Dart bug, and wait for the Dart team to implement it ;)
There's no support for this yet in Dart or JS.
The Xregexp JS library has support for generating fairly large character class regexps to support something like this. You may be able to generate the regexp, print it and cut and paste it into your app.
When would it be appropriate to localize a single ascii character?
for instance /, or | ?
is it ever necessary to add these "strings" to the localization effort?
just want to give some people the benefit of the doubt and make sure there's not something I didn't think of.
Generally it wouldn't be appropriate to use something like that except as a graphic element (which of course wouldn't be I18N'd in the first place, much less L10N'd). If you are trying to use it to e.g. indicate a ratio then you should have something like "%d / %d" instead, and localize the whole thing.
Yes, there are cases where these individual characters change in localization. This is not a comprehensive list, just examples I happen to know.
Not every locale uses , to separate thousands and . for the decimal. (However, these will usually be handled by your number formatter. If you do so yourself, you're probably doing it wrong. See this MSDN blog post by Michael Kaplan, Number format and currency format are not always the same.)
Not every language uses the same quotation marks (“, ”, ‘ and ’). See Wikipedia on Non-English Uses of Quotation Marks. (Many of these are only easy to replace if you use full quote marks. If you use the " and ' on your keyboard to mark both the start and end of sentences, you won't know which of two symbols to substitute.)
In Spanish, a question or exclamation is preceded by an inverted ? or !. ¿Question? ¡Exclamation! (Obviously, you can't fix this with a locale substitution for a single character. Any questions or exclamations in your application should be entire strings anyway, unless you're writing some stunningly intelligent natural language generator.)
If you do find a circumstance where you need to localize these symbols, be extra cautious not to accidentally localize a symbol like / used as a file separator, " to denote a string literal or ? for a search wildcard.
However, this has already happened with CSV files. These may be separated by ,, or may be separated by the local list separator. See What would happen if you defined your system's CSV delimiter as being a quotation mark?
In Greek, questions end with a semicolon rather than ?, so essentially the ? is replaced with ; ... however, you should aim to always translate the question as a complete string including question mark anyway.
I've been playing with this for an hour or tow and have found myself at a road block with the Lua pattern matching utilities. I am attempting to match all quoted text in a string and replace it if needed.
The pattern I have come up with so far is: (\?[\"\'])(.-)%1
This works in some cases but, not all cases:
Working: "This \"is a\" string of \"text to\" test with"
Not Working: "T\\\"his \"is\' a\" string\" of\' text\" to \"test\" wit\\\"h"
In the not working example I would like it to match to (I made a function that gets the matches I desire, I'm just looking for a pattern to use with gsub and curious if a lua pattern can do this):
string
a" string" of
is' a" string" of' text
test
his "is' a" string" of' text" to "test" wit
I'm going to continue to use my function instead for the time being, but am curious if there is a pattern I could/should be using and i'm just missing something with patterns.
(a few edits b/c I forgot about stackoverflows formating)
(another edit to make a non-html example since it was leading to assumptions that I was attempting to parse html)
Trying to match escaped, quoted text using regular expressions is like trying to remove the daisies (and only the daises) from a field using a lawnmower.
I made a function that gets the matches I desire
This is the correct move.
I'm curious if a lua pattern can do this
From a practical point of view, even if a pattern can do this, you don't want to. From a theoretical point of view, you are trying to find a double quote that is preceded by an even number of backslashes. This is definitely a regular language, and the regular expression you want would be something like the following (Lua quoting conventions)
[[[^\](\\)*"(.-[^\](\\)*)"]]
And the quoted string would be result #2. But Lua patterns are not full regular expressions; in particular, you cannot put a * after a parenthesized pattern.
So my guess is that this problem cannot be solved using Lua patterns, but since Lua patterns are not a standard thing in automata theory, I'm not aware of any body of proof technique that you could use to prove it.
The issue with escaped quotes is that, in general, if there's an odd number of backslashes before the quote, then it's escaped, and if there's an even number, it's not. I do not believe that Lua pattern-matching is powerful enough to represent this condition, so if you need to parse text like this, then you should seek another way. Perhaps you can iterate through the string and parse it, or you could find each quote in turn and read backwards, counting the backslashes until you find a non-backslash character (or the beginning of the string).
If you absolutely must use patterns for some reason, you could try doing this in a multi-step process. First, gsub for all occurrences of two backslashes in a row, and replace them with some sentinel value. This must be a value that does not already occur in the string. You could try something like "\001" if you know this string doesn't contain non-printable characters. Anyway, once you've replaced all sequences of two backslashes in a row, any backslashes left are escaping the following character. Now you can apply your original pattern, and then finally you can replace all instances of your sentinel value with two backslashes again.
Lua's pattern language is adequate for many simple cases. And it has at least one trick you don't find in a typical regular expression package: a way to match balanced parenthesis. But it has its limits as well.
When those limits are exceeded, then I reach for LPeg. LPeg is an implementation of a Parsing Expression Grammer for Lua, and was implemented by one of Lua's original authors so the adaptation to Lua is done quite well. A PEG allows specification of anything from simple patterns through complete language grammars to be written. LPeg compiles the grammar to a bytecode and executes it extremely efficiently.
you should NOT be trying to parse HTML with regular expressions, HTML and XML are NOT regular languages and can not be successfully manipulated with regular expressions. You should use a dedicated HTML parser. Here are lots of explanations why.