I'm trying to, given a unicode character, find out the "CharCode" for that char.
What is the opposite of ChrW in vb.net (or other code which doesnt bruteforce it)?
You need AscW - documentation here.
Related
There are times when you need to input modified variables with diacritical marks, or superscripts.
Seems like declare_index_properties allows doing it at the stage of display print.
But it is neither simple, nor very useful in formulas.
is there a simple way of adding hats, umlauts, and ', "strokes on top of a symbol, making it distinguishable from the symbol without such mark both to interpreter and to human eye?
Maxima doesn't have a notion of declaring a symbol to have diacritical marks or other combining marks on it. However, Maxima allows Unicode characters in symbol names if the underlying Lisp implementation allows Unicode; almost all of them allow Unicode. GCL is the only Lisp implementation, so far as I know, which doesn't handle Unicode correctly.
WxMaxima appears to allow Unicode characters to be input. At least, it worked that way when I tried some examples. Command-line Maxima allows Unicode if the terminal it is running in allows Unicode.
I think any Unicode character should be OK in a string. For symbols, any character which passes ALPHA-CHAR-P (a build-in Lisp function) can be part of a symbol name. Also, any character which is declared to be alphabetic (via declare("x", alphabetic) where x is the character in question) can be part of a symbol name.
I think wxMaxima has some capability to allow the user to select characters with diacritical marks from a menu; I haven't tried it. When I want to use Unicode characters, I end up just pasting them from a web page or something. I have used https://www.w3.org/2001/06/utf-8-test/UTF-8-demo.html as a source of characters in the past.
The IBM i implementation of regex uses apostrophes (instead of e.g. slashes) to delimit a regex string, i.e.:
... where REGEXP_SUBSTR(MYFIELD,'myregex_expression')
If I try to use an apostrophe inside a [group] within the expression, it always errors - presumably thinking I am giving a closing quote. I have tried:
- escaping it: \'
- doubling it: '' (and tripling)
No joy. I cannot find anything relevant in the IBM SQL manual or by google search.
I really need this to, for instance, allow names like O'Leary.
Thanks to Wiktor Stribizew for the answer in his comment.
There are a couple of "gotchas" for anyone who might land on this question with the same problem. The first is that you have to give the (presumably Unicode) hex value rather than the EBCDIC value that you would use, e.g. in ordinary interactive SQL on the IBM i. So in this case it really is \x27 and not \x7D for an apostrophe. Presumably this is because the REGEXP_ ... functions are working through Unicode even for EBCDIC data.
The second thing is that it would seem that the hex value cannot be the last one in the set. So this works:
^[A-Z0-9_\+\x27-]+ ... etc.
But this doesn't
^[A-Z0-9_\+-\x27]+ ... etc.
I don't know how to highlight text within a code sample, so I draw your attention to the fact that the hyphen is last in the first sample and second-to-last in the second sample.
If anyone knows why it has to not be last, I'd be interested to know. [edit: see Wiktor's answer for the reason]
btw, using double quotes as the string delimiter with an apostrophe in the set didn't work in this context.
A single quote can be defined with the \x27 notation:
^[A-Z0-9_+\x27-]+
^^^^
Note that when you use a hyphen in the character class/bracket expression, when used in between some chars it forms a range between those symbols. When you used ^[A-Z0-9_\+-\x27]+ you defined a range between + and ', which is an invalid range as the + comes after ' in the Unicode table.
Is anyone aware of a smalltalk library for converting Unicode to ascii?
I'm hoping that it will be somewhat intelligent, i.e. remove diacritical
marks. Non-ascii characters would either be removed or replace with
something like an underscore. E.g.:
"ěščřžýáíé ❤"
would be converted to:
"escrzyaie _"
or:
"escrzyaie "
Thanks,
Alistair
As was clarified in the comments, my goal was to be able to convert
filenames containing non-ascii / non-printable characters into something
that would still be meaningful but only contain ascii characters.
Using the Diacritics library kindly pointed out by Peter I ended up
writing a small class that does the conversion. If you're interested,
it is at:
https://github.com/akgrant43/AkgMiscellaneousUtilities/tree/master/mc/AKG-AsciiFilename.package
Thanks for all the assistance!
I'm trying to make a console-based program that makes use of ANSI escape codes with GNU Smalltalk. I can't seem to figure out how to go about printing a string object formatted with ANSI escape codes. I've tried the following.
'\x1b[31mHi' displayNl
This prints the entire string, including the escape code, without any formatting. I would have expected this to print "Hi" in red (and then everything else in the console after that, as I didn't reset the color.)
After googling a bit, I was able to find a couple issues on mailing lists where people were trying to produce things like newlines using "\n". Most of the answers were using the Transcript object's cr method, but I didn't find anything about colors in the textCollector class.
It looks like it shouldn't be all that hard to create my own module in C to achieve this functionality, but I'd like to know if there's a better way first.
I'm aware of the ncurses bindings, but I'm not sure that'd be practical for just making certain pieces of text in the program colored. So, is there a standard way of outputting colored text to the terminal in GNU Smalltalk using ANSI escape sequences?
Ended up getting an answer on the GNU Smalltalk mailing list. Looks like you can use an interpolation operator to achieve this.
For example ('%1[31mHi' % #($<16r1B>)) displayNl. would change the color to red, and ('%1[34mHi' % #($<16r1B>)) displayNl. would change the color to blue.
Basically, the % operator looks for a sequences that look like "%(number)" and replaces them with the objects in the array to the right of the operator. In our case, the array has one item, which is the ascii escape character in hexadecimal. So the "%1" in "%1[31mHi' is being replaced with the escape character, and then printed.
(This answer was stolen almost verbatim from Paolo on the GNU Smalltalk mailing list.)
I have a Sql statament using special character (ex: ('), (/), (&)) and I don't know how to write them in my VB.NET code. Please help me. Thanks.
Find out the Unicode code point for the character (from http://www.unicode.org) and then use ChrW to convert from the code point to the character. (To put this in another string, use concatenation. I'm somewhat surprised that VB doesn't have an escape sequence, but there we go.)
For example, for the Euro sign (U+20AC) you'd write:
Dim euro as Char = ChrW(&H20AC)
The advantage of this over putting the character directly into source code is that your source code stays "just pure ASCII" - which means you won't have any strange issues with any other program trying to read it, diff it, etc. The disadvantage is that it's harder to see the symbol in the code, of course.
The most common way seems to be to append a character of the form Chr(34)... 34 represents a double quote character. The character codes can be found from the windows program "charmap"... just windows/Run... and type charmap
If you are passing strings to be processed as SQL statement try doubling the characters for example.
"SELECT * FROM MyRecords WHERE MyRecords.MyKeyField = ""With a "" Quote"" "
The '' double works with the other special characters as well.
The ' character can be doubled up to allow it into a string e.g
lSQLSTatement = "Select * from temp where name = 'fred''s'"
Will search for all records where name = fred's
Three points:
1) The example characters you've given are not special characters. They're directly available on your keyboard. Just press the corresponding key.
2) To type characters that don't have a corresponding key on the keyboard, use this:
Alt + (the ASCII code number of the special character)
For example, to type ¿, press Alt and key in 168, which is the ASCII code for that special character.
You can use this method to type a special character in practically any program not just a VB.Net text editor.
3) What you probably looking for is what is called 'escaping' characters in a string. In your SQL query string, just place a \ before each of those characters. That should do.
Chr() is probably the most popular.
ChrW() can be used if you want to generate unicode characters
The ControlChars class contains some special and 'invisible' characters, plus the quote - for example, ControlChars.Quote