boofaq
How to contribute to the Boofaq?
What will happen if you mail your boo programming
problems to the authors?
Boofaq1: General Questions about boo
Who supports boo? Who develops it? Why is it free?
Which version of boo should I use?
What are boo 1, boo 2, or boo 3?
How does boo compare with other languages like Java,
Python, C, C++, REXX, Scheme or Tcl?
When shouldn’t I program in boo?
What’s the difference between boo and c-sharp?
Is it a boo program or a boo script?
How can I convince others to use boo?
Boofaq2: Obtaining and Learning about boo
What machines support boo? Where do I get it?
How can I get a binary version of boo?
I don’t have a C compiler. How can I build my own boo
compiler?
I copied the boo compiler binary from one machine to
another, but it doesn’t work.
What modules and extensions are available for boo?
Is there an ISO or ANSI certified version of boo?
Where can I get information on boo?
What are the boo newsgroups on Usenet? Where do I post
questions?
Where should I post source code?
Which magazines have boo content?
What mailing lists are there for boo?
Where are the archives for mono and mono-devel?
Where can I buy a commercial version of boo?
What is csharp.com, csharp-station.com,
csharphelp.com, codeproject.com, etc?
How can I use boo interactively?
How do I find which modules/libraries are installed on
my system?
How do I debug my boo programs?
How do I profile my boo programs?
How do I cross-reference my boo programs?
Is there a pretty-printer (formatter) for boo?
Is there an IDE or Windows boo editor?
Where can I get boo macros for vi?
Where can I get csharp-mode for emacs?
How can I use curses with boo?
How can I use X or Tk with boo?
How can I make my boo program run faster?
How can I make my boo program take less memory?
Is it safe to return a reference to a local or lexical
data?
How can I free an array or hash so my program shrinks?
How can I make my CGI script more efficient?
How can I hide the source for my boo program?
How can I compile my boo program into byte code or C?
How can I get #!/usr/bin/csharp to work on [MS-DOS,
NT, … ] ?
Can I write useful boo programs on the command line?
Why don’t boo one-liners work on my DOS/Mac/VMS
system?
Where can I learn about CGI or Web programming in boo?
Where can I learn about object-oriented boo
programming?
Where can I learn about linking C with boo?
I’ve read XYZ but I can’t embed boo in my C program;
what am I doing wrong?
When I tried to run my script, I got this message.
What does it mean?
What’s MakeMaker? [x:What is MSBUILD or Nant?]
Why isn’t my octal data interpreted correctly?
Does boo have a round() function? What about ciel() and
floor()? Trig functions?
How do I convert between numeric
representations/bases/radixes?.
Why doesn’t & work the way I want it to?
How do I perform an operation on a series of integers?
How can I output Roman numerals?
Why aren’t my random numbers random?
How do I get a random number between X and Y?
How do I find the day or week of the year?
How do I find the current century or millennium?
How can I compare two dates and find the difference?
How can I take a string and turn it into epoch
seconds?
How can I find the Julian Day?
How do I find yesterday’s date?
Does boo have a Year 2000 problem? Is boo Y2K
compliant?
How do I remove consecutive pairs of characters?
How do I expand function calls in a string?
How do I find matching/nesting anything?
How do I expand tabs in a string?
How do I reformat a paragraph?
How can I access or change N characters of a string?
How do I change the Nth occurrence of something?
How can I count the number of occurrences of a
substring within a string?
How do I capitalize all the words on one line?
How can I split a [character] delimited string except
when inside [character]?
How do I strip blank space from the beginning/end of a
string?
How do I pad a string with blanks or pad a number with
zeroes?
How do I extract selected columns from a string?
How do I find the soundex value of a string?
How can I expand variables in text strings?
What's wrong with always quoting "$vars"?
Why don't my <<HERE documents work?
What is the difference between a list and an array?
What is the difference between $array[1] and
@array[1]?
How can I remove duplicate elements from a list or
array?
How can I tell whether a certain element is contained
in a list or array?
How do I compute the difference of two arrays? How do
I compute the intersection of two arrays?
How do I test whether two arrays or hashes are equal?
How do I find the first array element for which a
condition is true?
How do I handle circular lists?
How do I shuffle an array randomly?
How do I process/modify each element of an array?
How do I select a random element from an array?
How do I permute N elements of a list?
How do I sort an array by (anything)?
How do I manipulate arrays of bits?
Why does defined() return true on empty arrays and
hashes?
Data: Hashes (Associative Arrays) [x:Dictionaries]
How do I process an entire hash?
What happens if I add or remove keys from a hash while
iterating over it?
How do I look up a hash element by value?
How can I know how many entries are in a hash?
How do I sort a hash (optionally by value instead of
key)?
How can I always keep my hash sorted?
What's the difference between "delete" and
"undef" with hashes?.
Why don't my tied hashes make the defined/exists
distinction?
How do I reset an each() operation part-way through?
How can I get the unique keys from two hashes?
How can I store a multidimensional array in a DBM
file?
How can I make my hash remember the order I put
elements into it?
Why does passing a subroutine an undefined element in
a hash create it?
How can I make the boo equivalent of a C structure/C++
class/hash or array of hashes or arrays?
How can I use a reference as a hash key?
How do I handle binary data correctly?
How do I determine whether a scalar is a
number/whole/integer/float?
How do I keep persistent data across program calls?
How do I print out or copy a recursive data structure?
How do I define methods for every class/object?
How do I verify a credit card checksum?
How do I pack arrays of doubles or floats for XS code?
How do I flush/unbuffer an output filehandle? Why must
I do this?
How do I change, delete, or insert a line in a file,
or append to the beginning of a file?
How do I count the number of lines in a file?
How can I use Perl's -i option from within a boo
program?
How do I make a temporary file name?
How can I manipulate fixed-record-length files?
How can I use a filehandle indirectly?
How can I set up a footer format to be used with
write()?
How can I write() into a string?
How can I output my numbers with commas added?
How can I translate tildes (~) in a filename?
How come when I open a file read-write it wipes it
out?
Why do I sometimes get an "Argument list too
long" when I use <*>?
Is there a leak/bug in glob()?
How can I open a file with a leading ">"
or trailing blanks?
How can I reliably rename a file?
Why can't I just open(FH, ">file.lock")?
I still don't get locking. I just want to increment
the number in the file. How can I do this?
How do I randomly update a binary file?
How do I get a file's timestamp in boo?
How do I set a file's timestamp in boo?
How do I print to more than one file at once?
How can I read in an entire file all at once?
How can I read in a file by paragraphs?
How can I read a single character from a file? From
the keyboard?
How can I tell whether there's a character waiting on
a filehandle?
How do I dup() a filehandle in boo?
How do I close a file descriptor by number?
Why can't I use "C:\temp\foo" in DOS paths?
Why doesn't `C:\temp\foo.exe` work?
Why doesn't glob("*.*") get all the files?
How do I select a random line from a file?
Why do I get weird spaces when I print an array of
lines?
How can I hope to use regular expressions without
creating illegible and unmaintainable code?
I'm having trouble matching over more than one line.
What's wrong?
How can I pull out lines between two patterns that are
themselves on different lines?.
I put a regular expression into $/ but it didn't work.
What's wrong?
How do I substitute case insensitively on the LHS
while preserving case on the RHS?
How can I make \w match national character sets?
How can I match a locale-smart version of /[a-zA-Z]/?
How can I quote a variable to use in a regex?
How do I use a regular expression to strip C style
comments from a file?
Can I use regular expressions to match balanced text?
What does it mean that regexes are greedy? How can I
get around it?
How do I process each word on each line?
How can I print out a word-frequency or line-frequency
summary?
How can I do approximate matching?
How do I efficiently match many regular expressions at
once?
Why don't word-boundary searches with \b work for me?
Why does using $&, $`, or $' slow my program down?
What good is \G in a regular expression?
Are regexes DFAs or NFAs? Are they POSIX compliant?
What's wrong with using grep in a void context?
How can I match strings with multibyte characters?
How do I match a regular expression that's in a
variable?
Boofaq7: General boo Language Issues
Can I get a BNF/yacc/RE for the boo language?
What are all these $@%&* punctuation signs, and
how do I know when to use them?.
Do I always/never have to quote my strings or use
semicolons and commas?
How do I skip some return values?
How do I temporarily block warnings?
Why do boo operators have different precedence than C
operators?
How do I declare/create a structure?
How can I tell if a variable is tainted?
What is variable suicide and how can I prevent it?
How can I pass/return a {Function, FileHandle, Array,
Hash, Method, Regex}?
How do I create a static variable?
What's the difference between dynamic and lexical
(static) scoping? Between local() and my()?
How can I access a dynamic variable while a similarly
named lexical is in scope?
What's the difference between deep and shallow
binding?
Why doesn't "my($foo) = <FILE>;" work
right?
How do I redefine a builtin function, operator, or
method?
What's the difference between calling a function as
&foo and foo()?
How do I create a switch or case statement?
How can I catch accesses to undefined variables,
functions, or methods?
Why can't a method included in this same file be
found?
How can I find out my current package?
How can I comment out a large block of boo code?
How can I use a variable as a variable name?
What does "bad interpreter" mean?
How do I find out which operating system I'm running
under?
How come exec() doesn't return?
How do I do fancy stuff with the
keyboard/screen/mouse?
How do I print something out in color?
How do I read just one key without waiting for a
return key?
How do I check whether input is ready on the keyboard?
How do I ask the user for a password?
How do I read and write the serial port?
How do I decode encrypted password files?
How do I start a process in the background?
How do I trap control characters/signals?
How do I modify the shadow password file on a Unix
system?
How do I set the time and date?
How can I sleep() or alarm() for under a second?
How can I measure time under a second?
How can I do an atexit() or setjmp()/longjmp()?
(Exception handling)
How can I call my system's unique C functions from boo?
Where do I get the include files to do ioctl() or
syscall()?
Why do setuid boo scripts complain about kernel
problems?
How can I open a pipe both to and from a command?
Why can't I get the output of a command with system()?
How can I capture STDERR from an external command?
Why doesn't open() return an error when a pipe open
fails?
What's wrong with using backticks in a void context?
How can I call backticks without shell processing?
Why can't my script read from STDIN after I gave it
EOF (^D on Unix, ^Z on MS-DOS)?.
How can I convert my shell script to boo?
Can I use booto run a telnet or ftp session?
How can I write expect in boo?
Is there a way to hide boo's command line from
programs such as "ps"?
How do I close a process's filehandle without waiting
for it to complete?
How do I fork a daemon process?
How do I find out if I'm running interactively or not?
How do I timeout a slow event?
How do I avoid zombies on a Unix system?
How do I make a system() exit on control-C?
How do I open a file without blocking?
How do I tell the difference between errors from the
shell and boo?
How do I install a module from CPAN?
What's the difference between require and use?
How do I keep my own module/library directory?
How do I add the directory my program lives in to the
module/library search path?
How do I add a directory to my include path (@INC) at
runtime?
What is socket.ph and where do I get it?
What is the correct form of response from a CGI
script?
My CGI script runs from the command line but not the
browser. (500 Server Error)
How can I get better error messages from a CGI
program?
How do I remove HTML from a string?
How do I download a file from the user's machine? How
do I open a file on another machine?
How do I make an HTML pop-up menu with boo?
How do I automate an HTML form submission?
How do I decode or create those %-encodings on the
web?
How do I redirect to another page?
How do I put a password on my web pages?
How do I edit my .htpasswd and .htgroup files with boo?
How do I make sure users can't enter values into a
form that cause my CGI script to do bad things?
How do I check a valid mail address?
How do I decode a MIME/BASE64 string?
How do I return the user's mail address?
How do I use MIME to make an attachment to a mail
message?
How do I find out my hostname, domainname, or IP
address?
How do I fetch a news article or the active
newsgroups?
How do I fetch/put an FTP file?
The Boofaq is a copy of perlfaq with questions answered in boo terms instead of perl terms. Perl has its roots in Unix and so many questions take a Mono instead of Microsoft answer approach only because Mono is the leading boo runtime on Unix. The authors wish to thank the authors of perlfaq for providing perlfaq as a perl resource. As former (and sometimes current) perl programmers we recognize that perlfaq has helped us be great perl programmers. When transitioning from perl to boo it was often easy to think in terms of perl and move that to boo. Sometimes this was a good thing, other times it was not. But rather than wade through API documentation in MSDN or Monodoc we wanted something like perlfaq.
When teaching an mentoring new perl programmers, my answer to their questions was often “That is in the perlfaq.” Or “Did look in perlfaq4?” When I started programming boo and trying to influence some of these same programmers, I noticed that they often had the same questions as they did before and that they didn’t know where to start looking for the answer. Some of the intent of Boofaq is to bridge this gap of information literacy. Another intent is to act as a reference for common questions. Many answers can be found in MSDN, but often diving through MSDN can be slow and difficult. Google yields many good answers to questions, but sometimes finding the right search phrase is difficult especially when namespaces are common to other languages or you are dealing with regular expressions.
You can mail corrections, additions, and suggestions to <boofaq-workers@lists.xmtp.net>.
We will make fun of you. j/k. Probably nothing. We might try to help. We might try to reply. We might not. We aren’t a free programming help service. More than likely we will point you to the question in the faq that most closely resembles your problem, or we will point you to MSDN or boo documentation.
Very general, high-level questions about boo.
boo is an object oriented statically typed programming language for the Common Language Infrastructure with a python inspired syntax and a special focus on compiler and language extensibility. Rodrigo B. de Oliveira created boo by due to his frustration with existing systems and his love for the CLI. He wanted to use python but use the .net framework.
The development community at large supports boo. Volunteers develop it as open source software. It is free for most of the same reasons that other languages and development environments are free.
You should use the latest possible boo version that is possible in your environment.
The release of boo 0.7.8 was the last release to support .net 1.1.
I don’t know.
boo is very stable. Between releases there is very little chance of breaking source level compatibility. There is even less chance at the byte code level (aka MSIL or CIL, not boo, but important to know). The development of boo is very open which adds to its stability. New releases do add new features often.
“No, [boo] is easy to start learning and easy to keep
learning. It looks like most programming languages with which you are likely to
have experience.“
boo seems to have very few “ah-ha” moments when learning it. While boo does have its share of “devil in the details” things to know about, these seem to be edge cases. These edge cases seem to be small. The average programmer can be up and running and writing boo code in short time. As with most languages, mastering the edge cases can take quite a bit longer.
“Favorable in some areas, unfavorably in others.”
boo is most like python in that it compiles to a bytecode that is then run by a jitter to execute native code on a given platform. boo is also similar to python in that it is “object oriented”.
Generics in boo are more like templates in C++ or since they are CLR generics, they are most like C# generics. However where templates in C++ are expanded by the pre-compiler, in boo generics are known about at runtime (thus generics are a .NET runtime feature with boo language support). There is a tradeoff here. There are things that C++ templates can do that simply cannot be done with boo generics, however boo generics have this benefit of runtime awareness so it too can do things that C++ generics cannot. One biggie is that while C++ templates would create a new type for every template type, boo shares it generic type implementation for all reference types. This leads to much less code bloat.
boo is less like Perl, or REXX because these are dynamic typed languages. This line is definitely blurring as things like IronPython and IronRuby are released. The DLR aides in running dynamic languages on .NET. Modern Python and Ruby aren’t really interpreted anyway. These languages follow a similar compile to bytecode and then run in a managed runtime as boo does. The difference is that compilation takes place on invocation rather than before. Support for compile first is also available in boo. Boo is rare and maybe even unique in the regard that it can be both compiled and interpreted. The Dynamic Language Runtime is bridging the gap between these languages through use of the .NET runtime. While boo will probably never use or run on the DLR, you might consider using Python on DLR to interoperate with your boo.
Yes.
“When your manager forbids it – but consider replacing them J.”
Another answer might be: When you cannot afford the costs of a managed environment. These cases are few and you might reconsider if you think you cannot afford these costs. They are often surprisingly low. Currently even light 3d graphics is done in boo using XNA. However the latest photo-realistic 3d environment game engine is probably not well suited to be written in boo.
I am not sure. Probably copyright. They are pronounced the same.
Either or both! boo can be interpreted like Perl or it can be compiled like C# or Java. This makes some of the questions in this faq not make some sense. We will refer those questions to here.
I sometimes call boo programs “scripts” if they do very simple things and I’ve written them in a script style, for example, one big main method. Or complete lack of OO design. For most “scripts” OO design would be overkill” – JRW
“JAPH stands for ‘Just another Perl hacker’”
“Appeal to their self interest!”
Where to find source and documentation for boo, support and related matters.
Any machine which can run .NET code can run boo. The Microsoft .NET implementation can run on x86, x86_64 and, I think, also Itanium.
The Mono .NET implementation can run on many more platforms. A complete list is available here: http://www.mono-project.com/Supported_Platforms
You can get boo from http://boo.codehaus.org/ You will need a .NET runtime, and preferably the latest .NET runtime. You probably already have some version of .NET if you are running a Microsoft operating system. You can get Mono by downloading it and installing it. If you are running Linux it may be easier to use your distributions package management system to install Mono. You can download Mono here: http://www.mono-project.com/Downloads
Ubuntu Linux ships with both mono and boo. You can install boo by simply running “apt-get install boo”.
The source and CLI binary are available from the boo website. See “Where do I get it?”
“Since you don't have a C compiler, you're doomed and your
vendor should be sacrificed to the Sun gods. But that doesn't help you.”
You only need a C# compiler. See the csharpfaq and the Mono project.
“That's probably because you forgot libraries, or library
paths differ. You really should build the whole distribution on the machine it
will eventually live on…”
I’ll assume you are referring to Mono in which case you should read their INSTALL file and their documentation.
The extensible compiler architecture used by boo is documented in the advanced features section of the boo language guide: http://boo.codehaus.org/Boo+Compiler
This is a bad copy from the perlfaq that doesn’t match well with boo. boo has numerous free and commercial libraries available for it. There is no CPAN equivalent for boo. boo libraries are not specific to boo but will work with any .NET language. These are often called .NET libraries. Many .NET libraries will work with both Microsoft and Mono, but some are specific to one or the other. Google is your best friend in finding libraries for boo. Also see Codeplex, Sourceforge and Mono itself.
Nope.
There aren’t any on Usenet. (Unfortunately) It is now a google world. There is a boolang google group at http://groups-beta.google.com/group/boolang. There are 4 email lists for boo developers (this means you are developing boo itself, not just programming using boo), announcements, source control logs, and an old archive list. These mailing lists are also available via gmane which means they are readable via NNTP. It isn’t Usenet, but its NNTP J. See http://boo.codehaus.org/Mailing+Lists for details.
“You should post source code to whichever group is most
appropriate…”
Getting involved in any online community is a great place to learn and to have others see your code. There are many online communities around boo there is not best one. The right one for you may not be the right one for someone else.
I don’t know of any boo books. Maybe someone should write one?
Unfortunately none.
See Google and Gmane respectively.
You cannot.
To the codehaus jira system: http://jira.codehaus.org/browse/BOO?report=com.atlassian.jira.plugin.system.project:openissues-panel
None of these are related to the boo programming language.
Programmer tools and programming support.
“Have you looked at CPAN (see perlfaq2)? The chances are that
someone has already written a module that can solve your problem. Have you read
the appropriate manpages?”
We don’t have CPAN or equivalent in the .NET (and thus boo) world. However there are still many of excellent libraries that can solve your problem. Please search before you reinvent the wheel.
Run booish the boo interactive shell. You can also use SharpDevelop, which comes with a boo plug-in. Just select Boo Interpreter from the View menu.
The booish, boo interactive shell is an interactive programming environment, but it is not a system shell. It is not a replacement for bash or even cmd.exe. However, it might be easy to make something to suit your needs.
Look for DLLs that are .NET assemblies. They could be anywhere on your system. The runtime has something called the Global Assembly Cache(GAC) which you may want to look at. The assemblies installed in the GAC could be considered the “installed modules” on your system. The GAC is installed in %WINDIR%\Assembly on Microsoft platforms and could be installed anywhere on a Mono platform. See your Mono distribution for more information.
Sharpdevelop provides an excellent debugger.
Microsoft offers a profiler as a separate download. http://www.microsoft.com/downloads/details.aspx?FamilyId=A362781C-3870-43BE-8926-862B40AA0CD0&displaylang=en
Mono has a few profiling tools. http://www.mono-project.com/Profile
Google for CLR profiler or .Net profiler to find many other profiling tools.
Perl has B::Xref. The Linux kernel uses LXR against its source. I know of no similar tools for boo. However, boo does have a standard for inline comment documentation.
SharpDevelop does a pretty nice job of pretty printing boo. pygments can pretty-print boo. (http://pygments.org/) boo is similar enough to python that a python pretty-printer might work too.
Yes, Exuberant ctags (http://ctags.sourceforge.net) has support for boo thanks to Steve Donovan’s sciboo project. (http://mysite.mweb.co.za/residents/sdonovan/sciboo.html)
SharpDevelop is the most popular IDE for boo. There is boo support in countless other editors. Gvim has good support. Notepad2 has good support. MonoDevelop is an open source IDE for .NET that runs on Linux.
Various boo.vim files are available for various boo branches. They are all in boo svn. See http://fisheye.codehaus.org/browse/boo/boo/branches/stable/extras/boo.vim?r=root: for the stable release.
You will have to write one.
http://www.mono-project.com/MonoCurses
http://www.mono-project.com/Gtk
I know of no wait to use the antiquated “tk” with boo or Mono.
http://www.mono-project.com/Performance_Tips
While this is mono documentation, nearly all of the concepts hold true for the MS runtime.
http://www.mono-project.com/Performance_Tips
While this is mono documentation, nearly all of the concepts hold true for the MS runtime.
This question is a bit of loaded perl, but it does have come boo corresponding questions. In a CLR there are reference types and there are value types. You can return a reference to a local, because the runtime is a garbage collected environment.
“Yes. Perl's garbage collection system takes care of this so
everything works out right.”
“You usually can't.”
999 times out of a thousand you don’t need to do this. There is much writing on how and why to NEVER call GC.Collect(). Please use google and read about GC.Collect(). If you need this level of memory management, any managed environment is probably not right for you.
CGI in boo? Well, it isn’t impossible. CGI is a gateway to ANY program. But with ASP.NET, CGI is not really used with boo. So the answer is: use ASP.NET
“Delete it. :-) Seriously, there are a number of (mostly
unsatisfactory) solutions with varying levels of "security".”
It is true in perl and it is true in boo or any .Net program. See Lutz Roder’s Reflector program or even Mono’s monodis program.
“In general, you can't do this.”
Runtime executed code is already byte code compiled. Use the booc.exe boo compiler.
boo is not perl J This is a bad copy from the perlfaq that doesn’t match well with boo.
boo programs compile to .NET bytecode. Windows operating systems know how to execute these .NET assemblies. They are .EXE files. In Linux you can help along these binary types by using [TODO: document that Linux file helper]
But most Mono programs simply create shell script wrappers for the compiled .exe files. E.g. ~/bin/MyProgram.exe has a shell script wrapper called ~/bin/MyProgram with contents “mono MyProgram.exe”.
If you find yourself asking the question and writing shell scripts with #!/usr/bin/booi at the top, maybe you should be using the boo compiler instead!
Not really. Certainly not like you can write one liners in perl.
See the previous question.
www.asp.net is a portal page run by Microsoft which is a great starting point for boo web programming. CastleProject has MonoRail which is an alternative to the WebForms style of ASP.NET Web development. Mono has some ASP.NET documentation http://www.mono-project.com/ASP.NET
See books, magazines, mailing lists, tutorials and websites.
P/Invoke is well documented by Microsoft and Mono.
There is also a very interesting Mono project called “linker”. http://www.mono-project.com/Linker
I’ll assume this is in regard to Mono. I know of no way to do this with the Microsoft runtime.
http://www.mono-project.com/Embedding_Mono
I’ll assume this is a compile time question. The compiler usually gives very good messages. If you can’t understand them, then you should probably read more.
boo programs are usually distributed with either a Makefile, or a MSBUILD csproj or sln file, or a nant build script.
Manipulating numbers, dates, strings, arrays, hashes, and miscellaneous data issues.
Everything I learned about perl I learned from perlfaq4 – JRW
“Internally, your computer represents floating-point numbers
in binary. Digital (as in powers of two) computers cannot store all numbers
exactly. Some real numbers lose precision in the process. This is a problem
with how computers store numbers and affects all computer languages, not just
Perl.”
Your int() is most probably working just fine. It's the numbers that aren't quite what you think.
First, see the answer to "Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?".
The boo language standard does not support octal characters constants by default.
The Math class in the System namespace has Round(), Ceiling() and Floor(). There are many overloads which allow setting precision.
The same Math class has common trig functions such as Sin(), Cos(), Tan(), Abs(), Asin(), Acos(), Atan(), Atan2(), Exp(), Log(), Pow(), Log10(), Sinh(), Cosh() and Tanh().
There are lots of ways. You could reference the Microsoft.VisualBasic assembly and use the Conversion class. You could use the Parse method available on many of the base types and use its NumberStyles overload. You may even be able to use System.Convert class to help you do it.
The boo language standard does not support octal or hexadecimal characters constants by default. The class methods given here will work in any .Net language.
>>> num = “A”
‘A’
>>> val = int.Parse(num, NumberStyles.HexNumber)
10
MSDN Topic titled “Parsing Numeric Strings” is a good source of more information.
Boo supports hexadecimal literals.
>>> x=0xa
10
>>> num = 10
>>> num.ToString(“X”)
‘A’
MSDN topic titled “Standard Numeric Format Strings” is a good source of more information.
This is the bitwise and operator. If you want a logical and, use &&. If you are looking to reference a memory location then you should have probably used a reference type. boo will automatically box and unbox value types. For more information on boxing see “Boxing and Unboxing” in the boo Programming Guide.
System.Drawing.Drawing2D.Matrix in the System.Drawing assembly provides support for 3-by-3 matrices. (from GDI+)
System.Windows.Media in WindowsBase assembly (from WPF) also provides support for 3-by-3 matrices.
System.Windows.Media.Media3D.Matrix3D in the PresentationCore assembly (from WPF) provides support for 4x4 matrix used for transformations in 3-D space.
A commercial general matrix library is available from bluebit software: http://www.bluebit.gr/NET/
When creating a brand spanking new multidimensional array, use this syntax:
foo = matrix(int, 2, 3, 4)
//That creates an empty 3
dimensional array.
//1st dimension will have 2 items, 2nd has 3, 3rd has 4
To call a function on each element in an array and collect the results use for
>>> x = [1,2,3,4,5]
>>> for i in x:
... print AddOne(i)
2
3
4
5
6
Or a slightly more complex example:
>>> def MyFunc(listOfInts):
... for I in listOfInts:
... yield I
>>> x = [1,2,3,4,5]
>>> List(MyFunc(x))
[2, 3, 4, 5, 6]
Computers are good at being predictable and bad at being
random (despite appearances caused by bugs in your programs :-).
You can seed System.Random by passing a value to the constructor, or you can use RNGCryptoServiceProvider instead. The interface for RNGCryptoServiceProvider is not the same as System.Random so your code may need changing. Better yet, use adapter pattern to create a compatible interface that gets its random numbers from RNGCryptoServiceProvider.
System.Random.Next() has an overload that takes minValue and maxValue as a parameter. This returns an int. System.Random.NextDouble() returns a double from 0 to 1. If you want a double between X and Y you will need to do the math yourself. For example for a double between 1.5 and 4.5
myNumber = 1.5 + (System.Random()).NextDouble() * (4.5-1.5)
DateTime has DayOfWeek and DayOfYear properties.
now = DateTime.Now
print “Today is ${now.DayOfWeek} and it is the ${now.DayOfYear} day of the year”
Divide DateTime.Year by 100 or 1000 +1
now = DateTime.Now
print “Today we live in Century ${ now.Year/100 + 1} and Millenium ${ now.Year/1000 +1}”
Use the subtract or overloaded minus operator. This will give a result of type TimeSpan. You can also subtract a TimeSpan from a DateTime to find another DateTime.
now = DateTime.Now
Christmas = DateTime( now.Year, 12, 25 )
threedays = TimeSpan(3,0,0,0)
print “Three days ago was ${ now - threedays }”
print “There is ${ Christmas - now } until Christmas”
DateTime has a Parse method (like most .NET primitives).
myDateTimeStr = “04/17/2007 14:30:00”
myDateTime = DateTime.Parse(myDateTimeStr)
epoch = DateTime(1970,1,1)
(myDateTime - epoch).TotalSeconds
http://www.codeproject.com/csharp/JalaliCalendar.asp
http://heybo.com/weblog/posts/254.aspx
Calculate the Julian Date
(DateTime.UtcNow - DateTime.MinValue).TotalDays + (DateTime(4713,1,1)-DateTime(1,1,1)).TotalDays +403
Or the modified Julian Date
(DateTime.UtcNow - DateTime(1858,11,17)).TotalDays
Or the day of the year (which is what some people think of as Julian day)
(System.Globalization.JulianCalendar()).GetDayOfYear(DateTime.Now)
DateTime.Now.AddDays(-1)
.NET does not have a Year 2000 problem. It is Y2K compliant. boo compiles to bytecode on .NET and thus does not have a Yeark 2000 problem and is Y2K compliant.
There are many ways. CastleProject has a Validation system which works well with MonoRail. EnterpriseLibrary from Microsoft had a Validation system.
It depends on what you mean. URL and Html escapes can be handled with HttpUtility class in System.Web namespace and assembly.
You can use the substitution operator to find pairs of
characters (or runs of characters) and replace them with a single instance. In
this substitution, we find a character in (.).
The memory parentheses store the matched character in the back-reference \1 and we use that to require that the same thing
immediately follow it. We replace that part of the string with the character in
$1.
/* s/(.)\1/$1/g; #is the perl regex */
stripped = /(.)\1/.Replace(“Haarlem”,”$1”)
Here is the same example as perlfaq converting Haarlem like in the Netherlands to Harlem like in New York.
There have been a number of attempts at a “exec” method for boo that uses CodeDom. I have not seen any one that did a very great job. boo is compiled to bytecode and then executed by a JIT engine. The method or function call you wish to perform may not exist at runtime.
That said, take a look at any of the boo DSL which may help you do what you want. Specifically take a look at Binsor in rhino-commons.
This isn't something that can be done in one regular
expression, no matter how complicated.
A regular expression is a representation of a Regular Language in the field of formal languages. They are equivalent to finite automaton. It can be proven that this is impossible. This is the task of a regular grammar.
Call reversed to make an enumerator and then call join.
>>> blah = “hello”
‘hello’
>>> join(List(reversed(blah)),"")
'olleh'
Array.Reverse will reverse an array in place.
'hello'
>>> chars = blah.ToCharArray()
(h, e, l, l, o)
>>> Array.Reverse(chars)
>>> string(chars)
'olleh'
' '
>>> mystring =
" <--
tab"
'\t<-- tab'
>>> expanded =
/\t/.Replace(mystring, tabSpaces)
' <-- tab'
[TODO: find a Text::Wrap and Text::Autoformat .NET Library or boo code]
Access can be done for a single character using the indexer in boo.
>>> blah
'hello'
>>> blah[2]
l
>>> blah[1]
e
Strings in .NET are immutable reference types so any change results in the creation of a new string. You can use string.Substring() or slice notation.
>>> jabh = "Just another boo hacker"
'Just another boo hacker'
>>> jabh.Substring(0,12) + " awesome " + jabh.Substring(13,10)
'Just another awesome boo
hacker'
>>> jabh[:13] + "awesome" + jabh[12:]
'Just another awesome boo
hacker'
You have to keep track of N yourself.
want = 3
sues = “One fish two fish red fish blue fish”
fisher = /(\w+)\s+fish\b/
count = 0
for match in fisher.Matches(sues):
count++
if count == 3:
print “the third fish is a ${match.Groups[1]} one.”
>>> blah = "there was an x in my string x in my string!"
'there was an x in my string x
in my string!'
>>> re = @/x in/
x in
>>> r = re.Matches(blah).Count
2
.NET regular expressions don’t support the \L \U modifiers like perl does. However, .NET provides a MatchEvaluator delegate which lets you call code for every match in a regular expression.
>>> def upper(m as Match):
... return m.Groups[1].Value.ToUpper()
...
>>> @/\b(\w)/.Replace("welcome
to the boofaq", upper )
'Welcome To The Boofaq'
>>>
To make the whole string
uppercase just use string.ToUpper
>>> “somestring”.ToUpper();
‘SOMESTRING’
You can (and probably should)
enable locale awareness of those characters by using the CultureInfo overload
>>> import
System.Globalization
>>> str1 = "this is some string man!"
'this is some string man!'
>>> str2 = str1.ToUpper(CultureInfo("en-US", false))
'THIS IS SOME STRING MAN!'
>>>
There is also
System.Globalization.TextInfo.ToTitleCase()
>>> myTI = CultureInfo("en-US",false).TextInfo
TextInfo - 1033
>>> myTI.ToTitleCase("welcome to the
boofaq")
'Welcome To The Boofaq'
>>>
Usually characters here are a comma and a quote. ODBC allows the use of an ODBC ADO.NET CSV DataProvider. There are multiple CSV parsers available at places like CodeProject.
Take the example case of trying to split a string that is comma-separated into its different fields. You can't use split(/,/) because you shouldn't split if the comma is inside quotes. For example, take a data line like this:
SAR001,"","Cimetrix,
Inc","Bob Smith","CAM",N,8,1,0,7,"Error, Core
Dumped"
Due to the restriction of the quotes, this is a fairly complex problem. Thankfully, we have Jeffrey Friedl, author of Mastering Regular Expressions, to handle these for us. He suggests (assuming your string is contained in $text):
@new = ();
push(@new, $+) while $text =~ m{
"([^\"\\]*(?:\\.[^\"\\]*)*)",? # groups the phrase inside the quotes
| ([^,]+),?
| ,
}gx;
push(@new, undef) if substr($text,-1,1) eq
',';
If you want to represent quotation marks inside a
quotation-mark-delimited field, escape them with backslashes (eg, "like
\"this\"".
This is Boofaq so you may or may not know perl. The above is a rather nice regular expression. We can get similar behavior with boo using this code.
text = "\"This is a Quoted Value\",1,2,CSV,omg
csv,\"Quotes, commas, and things\""
//+ re {"([^"\]*(?:\.[^"\]*)*)",?
| ([^,]+),? | ,} System.Text.RegularExpressions.Regex
re = Regex("\"([^\\\"\\]*(?:\\.[^\\\"\\]*)*)\",?"
+ @"|([^,]+),?" + @"|,")
value = []
for m in re.Matches(text):
values.Add(m.Groups[m.Groups.Count - 1].Value);
[TODO: this regex doesn’t work fix this!]
Use string.Trim(), string.TrimEnd(‘ ‘), string.TrimStart(‘ ‘);
Use the String(Char, Int32) constructor.
things = string(‘ ‘, 20) + “my stuff”
Or you can use the * operator:
>>> " "*20+"my stuff"
' my stuff'
If you know where the columns that contain the data are, you can use string.Substring to extract a single column
column = line.Substring(startColumn, length)
or you can use slicing
column = line[startColumn:length+startColumn]
You can use split if the columns are separated by whitespace or some other delimiter as long as the delimiter cannot appear as part of the data.
>>> line =
" fred barney
betty "
' fred barney
betty '
>>> line.Split(char(' '))
('', 'fred', 'barney', '', 'betty', '', '')
[TODO: what is soundex?]
Is this a good place for Levenshtein distance from
http://www.merriampark.com/ldcsharp.htm
boo just does it for you
foo = “Fred”
bar = “Barney”
“Say hello to ${foo} and ${bar}”
With boo you can’t do that, so it doesn’t apply. However the string class is often misunderstood. People say not to use + and to prefer string.Format. It turns out that the compiler itself has some optimizations for using + concatenation. Don’t prematurely optimize strings. You should just be aware that they are immutable reference types with value semantics. If you run into issues, then you can consider optimizing.
http://www.ayende.com/Blog/archive/2007/07/06/The-truth-about-string-concatenation-performance.aspx
With boo you can’t do that either! :0
This is VERY different than perl, so beware. In .NET arrays are more like C arrays. They are fixed length at time of creation. They represent a contiguous block of memory. Lists are anything that implements IList. Usually this is System.Collections.ArrayList or System.Collections.Generic.List<>
The generic List<> should almost always be preferred to use of ArrayList.
Array’s have a Length property. Lists have a Count property.
In boo there is also Boo.Lang.List which is what you get when you use [] notation. () notation give you a real array. Boo is smart enough to recognize if all the types of an array are the same and return an array of that type. Otherwise boo gives an System.Object[].
boo doesn’t have these language issues.
Use a Dictionary (hash). When you think the words “unique” or “duplicated”, think Dictionary keys.
If you don’t care about the order of the elements, you could just create the Dictionary and then extract eh keys.
words = [ "one", "two", "three",
"one", "four"
]
dict = { }
for s in words:
dict[s] = true
Hearing the word "in" is an indication that you
probably should have used a hash, not a list or array, to store your data.
Hashes are designed to answer this question quickly and efficiently. Arrays
aren't.
Both Array and List have an Exists method. List also has a Contains method.
// goodcolors = List<string>([ "Red",
"White", "Blue"
])
okcolors = [ "Teal", "Pink"
];