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  • reinventing the wheels: Node.JS/Event-driven programming v.s. Functional Programming?

    - by ivanTheTerrible
    Now there's all the hype lately about Node.JS, an event driven framework using Javascript callbacks. To my limited understanding, its primary advantage seems to be that you don't have to wait step by step sequentially (for example, you can fetch the SQL results, while calling other functions too). So my question is: how is this different, or better than just functional languages, like CL, Haskell, Clojure etc? If not better, then why don't people just do functional languages then (instead of reinventing the wheel with Javascript)? Please note that I have none experience in either Node.JS nor functional programming. So some basic explanation can be helpful.

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  • jquery dynatree class methods

    - by Jj Zhang
    I'm a new user of dynatree plugin. When I read the documentation, I found the list of tree and node class member functions, such as tree.getRoot(), node.countChildren(). However, when I tried to use them, it complained that no such methods were found. Here is a sample code I am testing with: var tree = ("#test").dynatree(treeData); var rootNode = tree.getRoot(); //not working var rootNode2 = ("#test").dynatree("getRoot"); //this works var numChildren = rootNode2.countChildren(); //not working Help please. Thanks. -JJ

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  • How to link a SQlite Extension Source File into Xcode for iPhone?

    - by crunchyt
    I use a statically linked library for Sqlite in an iPhone Xcode project. I am now trying to include a .C extension to Sqlite in this project. However, I am having trouble making the Sqlite in the build SEE the extension. The statically linked Sqlite library works fine. Also the .C extension works on my desktop, and builds fine as a statically linked library in Xcode. However, the custom functions it defines are missing when called. For example, I load the extension as so with no errors. SELECT load_extension('extension_name.so'); But when I try to call a function defined in the extension, I get this message DB Error: 1 "no such function: custom_function" Does anyone know much about linking a Sqlite extension into an Xcode project?

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  • Blackberry custom OVERLAY horizontal menu

    - by Dachmt
    Thanks to Max in this post, I made an horizontal menu. But now I'm trying to make an overlay menu, i I don't find how to do that... Let's see what i got first. So, I have a class MapScreen which display my map: public class MapScreen extends MenuScreen Then, I have in the same file the MenuScreen class like this that allows to display the horizontal menu when I press the MENU key: abstract class MenuScreen extends MainScreen { boolean mMenuEnabled = false; CyclicHFManager mMenuManager = null; public MenuScreen() { mMenuManager = new CyclicHFManager(); mMenuManager.setBorder(BorderFactory.createBevelBorder(new XYEdges(4, 0, 0, 0), new XYEdges(Color.DARKBLUE, 0, 0, 0), new XYEdges( Color.WHITE, 0, 0, 0))); mMenuManager.setBackground(BackgroundFactory .createLinearGradientBackground(Color.DARKBLUE, Color.DARKBLUE, Color.LIGHTBLUE, Color.LIGHTBLUE)); for (int i = 0; i < 10; i++) { Bitmap nBitmap = new Bitmap(60, 60); Graphics g = new Graphics(nBitmap); g.setColor(Color.DARKBLUE); g.fillRect(0, 0, 60, 60); g.setColor(Color.WHITE); g.drawRect(0, 0, 60, 60); Font f = g.getFont().derive(Font.BOLD, 40); g.setFont(f); String text = String.valueOf(i); g.drawText(text, (60 - f.getAdvance(text)) >> 1, (60 - f .getHeight()) >> 1); Bitmap fBitmap = new Bitmap(60, 60); g = new Graphics(fBitmap); g.setColor(Color.DARKBLUE); g.fillRect(0, 0, 60, 60); g.setColor(Color.GOLD); g.drawRect(0, 0, 60, 60); g.setFont(f); g.drawText(text, (60 - f.getAdvance(text)) >> 1, (60 - f .getHeight()) >> 1); BitmapButtonField button = new BitmapButtonField(nBitmap, fBitmap); button.setCookie(String.valueOf(i)); button.setPadding(new XYEdges(0, 18, 0, 18)); button.setChangeListener(new FieldChangeListener() { public void fieldChanged(Field field, int context) { Dialog.inform("Button # " + (String) field.getCookie()); } }); mMenuManager.add(button); } } protected boolean keyDown(int keycode, int time) { if (Keypad.KEY_MENU == Keypad.key(keycode)) { if (mMenuManager.getManager() != null) { delete(mMenuManager); mMenuManager.mCyclicTurnedOn = false; } else { add(mMenuManager); mMenuManager.getField(2).setFocus(); mMenuManager.mCyclicTurnedOn = true; } return true; } else { return super.keyDown(keycode, time); } }} And finally my menu manager: public class CyclicHFManager extends HorizontalFieldManager { int mFocusedFieldIndex = 0; public boolean mCyclicTurnedOn = false; public void focusChangeNotify(int arg0) { super.focusChangeNotify(arg0); if (mCyclicTurnedOn) { int focusedFieldIndexNew = getFieldWithFocusIndex(); if (focusedFieldIndexNew != mFocusedFieldIndex) { if (focusedFieldIndexNew - mFocusedFieldIndex > 0) switchField(0, getFieldCount() - 1); else switchField(getFieldCount() - 1, 0); } } else { mFocusedFieldIndex = getFieldWithFocusIndex(); } } private void switchField(int prevIndex, int newIndex) { Field field = getField(prevIndex); delete(field); insert(field, newIndex); }} So as it is like this, it is working: when I press the MENU key, the menu appears, i can navigate between buttons, and it disappear when I press again the same key. The only problem is my menu isn't overlaying my map, it pushes the content up. I tried with the menu manager like in your first response, resizing the content manager but it is the same result. Max gave me the link http://stackoverflow.com/questions/1497073/blackberry-fields-layout-animation to do so, but I really don't know how to use it to make it work in my project... Thank you for your help! UPDATE This works great, it's what I wanted. However, I still have a problem because I'm under 4.5. So first in the MenuHostManager constructor, I deleted the USE_ALL_HEIGHT and change setPositionChild(mMenuManager, 0, Display.getHeight() - mMenuManager.getPreferredHeight()); like this to have the menu at the bottom of the screen. It worked. Then, instead of drawing my bitmaps, I did this: Bitmap nBitmap = EncodedImage.getEncodedImageResource("menu" + i + ".png").getBitmap(); BitmapButtonField button = new BitmapButtonField(nBitmap, nBitmap); And it worked too (no rollover for now, later). So it is great! I also overwrite the Paint method of my CyclicHFManager to have a background color, because I can't use the BorderFactory and BackgroundFactory... My menu bar has a color for now so it's ok. Then, because of these 2 classes missing, in my BitmapButtonField I had to delete the 2 setBorder functions that change the borders. And now i have my buttons pretty big like normal buttons with borders... How can I make the same effect as the setBorder functions under 4.5? (BTW, setBorder is not working under 4.5 too...). Thank you!

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  • Knowledge base web app -- need a demo mode

    - by Smandoli
    I was contracted to build an on-line knowledge base that searches and cross-references many thousands of replacement parts for a niche industry. My client furnishes this app to his customers on a subscription basis. It uses MySQL and PHP and it works great. I want to deploy it in "demo mode" to sell my skills. I want the user to see the functions, but I have to guard the data for my client. My first idea was to obfuscate the results. That's at cross-purposes with showing how well it searches. I'm considering a limit on how many searches you can perform, but that's awkward too as someone could visit every day and get more answers than we would prefer. Other posts I've found are about letting people interact with an app, but without the challenge of protecting a big knowledge base. Can you suggest an approach? (Note, I put the tag obfuscation, but not sure it applies because java code obfuscation seems to be unrelated.)

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  • What useful GDB scripts have you used/written?

    - by nik
    People use gdb on and off for debugging, of course there are lots of other debugging tools across the varied OSes, with and without GUI and, maybe other fancy IDE features. I would like to know what useful gdb scripts you have written and liked. While, I do not mean a dump of commands in a something.gdb file that you source to pull out a bunch of data, if that made your day, go ahead and talk about it. Lets think conditional processing, control loops and functions written for more elegant and refined programming to debug and, maybe even for whitebox testing Things get interesting when you start debugging remote systems (say, over a serial/ethernet interface) And, what if the target is a multi-processor (and, multithreaded) system Let me put a simple case as an example... Say, A script that traversed serially over entries to locate a bad entry in a large hash-table that is implemented on an embedded platform. That helped me debug a broken hash-table once.

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  • Prototyping Object in Javascript breaks jQuery?

    - by blesh
    I have added a simple .js to my page that has some pretty mundane common-task sort of functions added to the Object and Array prototypes. Through trial and error I've figured out that adding any function to Object.prototype, no matter it's name or what it does causes javascript errors in jQuery: The culprit? Object.prototype.foo = function() { /*do nothing and break jQuery*/ }; The error I'm getting line 1056 of jquery-1.3.2.js, in the attr:function { } declaration: /*Object doesn't support this property or method*/ name = name.replace(/-([a-z])/ig, function(all, letter) { return letter.toUpperCase(); }); Apparently G.replace is undefined. While it's obvious that there's something I'm just not wrapping my head around with prototyping, I'm failing miserably to figure out what it is. To be clear, I'm not looking for a workaround, I have that handled... what I'm looking for is an answer to 'Why?'. Why does adding a function to Object.prototype break this bit of code?

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  • Why won't the VisualVM Profiler profile my application?

    - by Luke
    I've created a simple 1 file java application that iterates through a loop, calls some functions, allocates some memory, adds some numbers, etc. I run that application via eclipse's Run As->Java Application. The running application shows up in Java VisualVM under Local. I double click on that application and go to the Profiler tab. The default settings are: Start profiling from classes: my.main.package.** Do not profile classes: java.*, javax.*, sun.*, sunw.*, com.sun.* I click on CPU. The CPU and Memory buttons gray out. Nothing happens. The Status says profiling inactive. When my application terminates the Status says application terminated. What am I doing wrong here? Are there some settings I need to tweak? Do I need to set a VM flag when I launch my application?

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  • Break nested loop in Django views.py with a function

    - by knuckfubuck
    I have a nested loop that I would like to break out of. After searching this site it seems the best practice is to put the nested loop into a function and use return to break out of it. Is it acceptable to have functions inside the views.py file that are not a view? What is the best practice for the location of this function? Here's the example code from inside my views.py @login_required def save_bookmark(request): if request.method == 'POST': form = BookmarkSaveForm(request.POST) if form.is_valid(): bookmark_list = Bookmark.objects.all() for bookmark in bookmark_list: for link in bookmark.link_set.all(): if link.url == form.cleaned_data['url']: # Do something. break else: # Do something else. else: form = BookmarkSaveForm() return render_to_response('save_bookmark_form.html', {'form': form})

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  • Data Structure Behind Amazon S3s Keys (Filtering Data Structure)

    - by dimo414
    I'd like to implement a data structure similar to the lookup functionality of Amazon S3. For those of you who don't know what I'm taking about, Amazon S3 stores all files at the root, but allows you to look up groups of files by common prefixes in their names, therefore replicating the power of a directory tree without the complexity of it. The catch is, both lookup and filter operations are O(1) (or close enough that even on very large buckets - S3's disk equivalents - both operations might as well be O(1))). So in short, I'm looking for a data structure that functions like a hash map, with the added benefit of efficient (at the very least not O(n)) filtering. The best I can come up with is extending HashMap so that it also contains a (sorted) list of contents, and doing a binary search for the range that matches the prefix, and returning that set. This seems slow to me, but I can't think of any other way to do it. Does anyone know either how Amazon does it, or a better way to implement this data structure?

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  • Where do I find a good explanation of Javascript-ese

    - by tzenes
    I realize that title may require explanation. The language I first learned was C, and it shows in all my programs... even those not written in C. For example, when I first learned F# I wrote my F# programs like C programs. It wasn't until someone explained the pipe operator and mapping with anonymous functions that I started to understand the F#-ese, how to write F# like a F# programmer and not a C programmer. Now I've written a little javascript, mostly basic stuff using jquery, but I was hoping there was a good resource where I could learn to write javascript programs like a javascript programmer.

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  • jQuery selective hover

    - by Vitor
    Hello everyone, I'm trying to do a simple task with jQuery: I have a list of words which, when hovered, should fadeIn its corresponding image. For example: <a href="#" class="yellow">Yellow</a> <a href="#" class="blue">Blue</a> <a href="#" class="green">Green</a> <img src="yellow.jpg" class="yellow"> <img src="blue.jpg" class="blue"> <img src="green.jpg" class="green"> I'm currently doing it this way for each link/image: $('a.yellow').hover( function () { $('img.yellow').fadeIn('fast'); }, function () { $('img.yellow').fadeOut('fast'); }); The method above works fine, but as I'm still learning, I guess there's a better way to do that instead of repeating functions. Can anyone give me some light here? How can I improve this code?

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  • MATLAB: dealing with java.lang.String

    - by Jason S
    I seem to be stuck in Kafka-land, with a java.lang.String that I can't seem to use in MATLAB functions: K>> name name = Jason K>> sprintf('%s', name) ??? Error using ==> sprintf Function is not defined for 'java.lang.String' inputs. K>> ['my name is ' name] ??? Error using ==> horzcat The following error occurred converting from char to opaque: Error using ==> horzcat Undefined function or method 'opaque' for input arguments of type 'char'. how can I get a java.lang.String to convert to a regular MATLAB character array?

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  • Setting data source for reports in Crystal Reports 2008 Java (performance)

    - by Daniel
    Hi, we have Crystal Reports 2008 on the server, and use the Java SDK to display reports and convert them to PDF. Since the server hat its own database, we have to set the data source on the DatabaseController to make CR connect to this database. We do it like specified in the docs, and tried the functions in CRJavaHelper, but for a reason unknown to me setting the connection string takes 300ms to 1500ms. What is the fastest way to tell Crystal which datasource to use in its reports? I already saw a JNDI name somewhere, but i don't believe CR actually does a JNDI lookup to find an existing datasource, doesn't it?

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  • Graphviz DOT arrange Nodes in circles, layout too "compact"

    - by Ivo Wetzel
    I'm halfway there please see the edit OK here's my problem, I'm generating a graph of a python module, including all the files with their functions/methods/classes. I want to arrange it so, that nodes gather in circles around their parent nodes, currently everything is on one gargantuan horizontal row, which makes the thing 50k pixels wide and also let's the svg converter fail(only renders about the half of the graph). I went trough the docs(http://www.graphviz.org/doc/info/attrs.html) but couldn't find anything that seems to do the trick. So the question is: Is there a simple way to do this or do I have to layout the whole thing by myself? :/ EDIT: Thanks to Andrews comment I've got the right layout, the only problem now is that it's a bit to "compact"... so the question now is, how to fix this?

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  • Python 3: timestamp to datetime: where does this additional hour come from?

    - by Beau Martínez
    I'm using the following functions: # The epoch used in the datetime API. EPOCH = datetime.datetime.fromtimestamp(0) def timedelta_to_seconds(delta): seconds = (delta.microseconds * 1e6) + delta.seconds + (delta.days * 86400) seconds = abs(seconds) return seconds def datetime_to_timestamp(date, epoch=EPOCH): # Ensure we deal with `datetime`s. date = datetime.datetime.fromordinal(date.toordinal()) epoch = datetime.datetime.fromordinal(epoch.toordinal()) timedelta = date - epoch timestamp = timedelta_to_seconds(timedelta) return timestamp def timestamp_to_datetime(timestamp, epoch=EPOCH): # Ensure we deal with a `datetime`. epoch = datetime.datetime.fromordinal(epoch.toordinal()) epoch_difference = timedelta_to_seconds(epoch - EPOCH) adjusted_timestamp = timestamp - epoch_difference date = datetime.datetime.fromtimestamp(adjusted_timestamp) return date And using them with the passed code: twenty = datetime.datetime(2010, 4, 4) print(twenty) print(datetime_to_timestamp(twenty)) print(timestamp_to_datetime(datetime_to_timestamp(twenty))) And getting the following results: 2010-04-04 00:00:00 1270339200.0 2010-04-04 01:00:00 For some reason, I'm getting an additional hour added in the last call, despite my code having, as far as I can see, no flaws. Where is this additional hour coming from?

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  • Sharing memory among YACC, Lex, and C files

    - by sczizzo
    I have a YACC (Bison) grammar, a Lex (Flex) tokenizer, and a C program among which I need to share a struct (or really any variable). Currently, I declare the actual object in the grammar file and extern it wherever I need it (which is to say, my C source file), usually using a pointer to manipulate it. I have a shared header (and implementation) file between the C file and the grammar file with functions useful for manipulating my data structure. This works, but it feels a little uncomfortable. Is there a better way to share memory between the grammar and program?

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  • clear javascript console in Google Chrome

    - by Reigel
    Hi, I was wondering if I could clear up the console with some command.. console.log(), can print... is there a command to clear up console?.. I've tried to console.log(console); and got this functions below... assert: function assert() { [native code] } constructor: function Console() { [native code] } count: function count() { [native code] } debug: function debug() { [native code] } dir: function dir() { [native code] } dirxml: function dirxml() { [native code] } error: function error() { [native code] } group: function group() { [native code] } groupEnd: function groupEnd() { [native code] } info: function info() { [native code] } log: function log() { [native code] } markTimeline: function markTimeline() { [native code] } profile: function profile() { [native code] } profileEnd: function profileEnd() { [native code] } time: function time() { [native code] } timeEnd: function timeEnd() { [native code] } trace: function trace() { [native code] } warn: function warn() { [native code] } __proto__: Object [ I guess there's no way to clear up the console... but I wanted someone to say it to me... ]

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  • NSNumberFormatter crashing iPhone SDK 4.0b2

    - by Ward
    Hey there, I've got an app that's been in the app store for a while and functions perfectly on OS 3.1 - 3.13. However, when tested on 4.0b2 I noticed that it crashes in the same place every time, but only on the device, never on the simulator. I'm using a 3GS to test. On loadView I initialize an NSNumberFormatter object which is declared and retained in the interface so I have access to it everywhere. In my method I call it several times to convert string values into nsnumbers to be stored in a mutable dictionary. Here's an example: [myDictionary setObject:[myStyleFormatter numberFromString:@"1"] forKey:@"hours"]; [myDictionary setObject:[myStyleFormatter numberFromString:@"30"] forKey:@"minutes"]; [myDictionary setObject:[myStyleFormatter numberFromString:@"10"] forKey:@"seconds"]; For some reason it crashes as soon as it tries to set hours. The error is "attempt to insert nil value (key: hours)" Have I been doing something wrong all along? Has the api changed for 4.0b2? Thanks, Howie

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  • Android app (with felix) crashes with LinearAlloc exceeded capacity

    - by user1106000
    I am running apache felix and an osgi app on android (3.2). This works pretty well so far, but I have rather large chunks of data to load into the application (osgi bundles). The problem with that is that when I load the biggest chunk of data I get LinearAlloc exceeded capacity The error seems to come from LinearAlloc.c \#define DEFAULT_MAX_LENGTH (4*1024*1024) if (nextOffset > pHdr->mapLength) { /* * We don't have to abort here. We could fall back on the system * malloc(), and have our "free" call figure out what to do. Only * works if the users of these functions actually free everything * they allocate. */ LOGE("LinearAlloc exceeded capacity, last=%d\n", (int) size); dvmAbort(); } afaik in 3.2/4.x it is even 8*1024*1024, but I still hit that limit. I'm looking to get better insight on what causes this problem and how I might possibly be able to fix it. Any help would be appreciated.

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  • Why array size in llvm created by llvm's internal tools is not good enough for llvm?

    - by vava
    I'm getting strange error message from the following code: ArrayType * arrayType = ArrayType::get(Type::getInt32Ty(ctx), 0); stack = builder->CreateAlloca(arrayType, ConstantArray::get(arrayType, std::vector<Constant *>())); This code compiles fine but it gives me llvm::Value* getAISize(llvm::LLVMContext&, llvm::Value*): Assertion `Amt-getType() == Type::getInt32Ty(Context) && "Malloc/Allocation array size is not a 32-bit integer!"' failed. during execution. What's interesting, is that I never said of what type array size should be, it was created somewhere inside helper functions. So I naturally see no good reason for assert to be there. But I must be doing something wrong anyway, can you help me spot the problem? Thanks in advance. PS. LLVM, as good as it is, lacking documentation tremendously.

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  • ruby on rails named scope implementation

    - by Engwan
    From the book Agile Web Development With Rails class Order < ActiveRecord::Base named_scope :last_n_days, lambda { |days| {:conditions => ['updated < ?' , days] } } named_scope :checks, :conditions => {:pay_type => :check} end The statement orders = Orders.checks.last_n_days(7) will result to only one query to the database. How does rails implement this? I'm new to Ruby and I'm wondering if there's a special construct that allows this to happen. To be able to chain methods like that, the functions generated by named_scope must be returning themselves or an object than can be scoped further. But how does Ruby know that it is the last function call and that it should query the database now? I ask this because the statement above actually queries the database and not just returns an SQL statement that results from chaining.

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  • JavaScript setTimeout setInterval within one function

    - by dagoof
    I think I might be overtired but I cannot for the life of me make sense of this, and I think it's due to a lack of knowledge of javascript var itv=function(){ return setInterval(function(){ sys.puts('interval'); }, 1000); } var tout=function(itv){ return setTimeout(function(){ sys.puts('timeout'); clearInterval(itv); }, 5500); } With these two functions I can call a=tout(itv()); and get a looping timer to run for 5.5 seconds and then exit, essentially. By my logic, this should work but it simply is not var dotime=function(){ return setTimeout(function(){ clearInterval(function(){ return setInterval(function(){ sys.puts("interval"); }, 1000); }); }, 5500); } any insight in this matter would be appreciated.

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  • Using LINQ to SQL with multiple databases

    - by Stuart Ferguson
    I am working on a new project and hoping to use LINQ to SQL for the data access but have come across the following issue. I need to have my application access 3 databases with similar but not the same table structure, for example Database1 and Database 2 has a table called tblCustomer with 2 columns CustomerKey and CustomerName Database2 has a table called tblCustomer with 3 columns CustomerKey, CustomerName and CustomerPostCode I am looking for a solution that will allow me a query all three databases without the need for 3 GetCustomerList functions as Database1 and Database2 could use the same function as are the same structure, with an override function for database 3 to bring back the additional field. Is there a way i can declare a base datacontext class to handle Database 1 and 2 with an inherited version for Database 3. Thanks In Advance Stuart Ferguson

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  • How to Create a Temporary Function in Emacs Lisp

    - by Cristian
    I'm making some tedious calls to a bunch of functions, but the parameters will be determined at runtime. I wrote a simple function to keep my code DRY but giving it a name is unnecessary. I don't use this function anywhere else. I'm trying to do it the way I would in Scheme, but I get a void-function error: (let ((do-work (lambda (x y z) (do-x x) (do-y y) ;; etc ))) (cond (test-1 (do-work 'a 'b 'c)) (test-2 (do-work 'i 'j 'k)))) I could stick it all into an apply (e.g., (apply (lambda ...) (cond ...))) but that isn't very readable. Is there a better way?

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