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  • How to write (simple) macro?

    - by krzysz00
    I need to write a macro (with-hooks (monster method who what) &body body) for a game I'm writing. Monster is a CLOS object, method and who are strings and what is a function (#' notation). The macroexpansion would be something to the effect of (add-hook monster method who what) ,@body (remove-hook monster method who) I have absolutely no idea how to write such a macro, and I would appreciate some help.

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  • Does CLOS have an eql specialization dispatch on strings?

    - by mhb
    Examples of what you can do. (defmethod some-fn ((num real)) (print "an integer")) (defmethod some-fn ((num real)) (print "a real")) (defmethod some-fn ((num (eql 0))) (print "zero")) (some-fn 19323923198319) "an integer" (some-fn 19323923198319.3) "a real" (some-fn 0) "zero" It also works with a general 'string type. (defmethod some-fn ((num string)) (print "a string")) (some-fn "asrt") "a string" Not with a specific string, however (defmethod some-fn ((num (eql "A")) (print "a specifict string"))) => doesn't compile I imagine it doesn't work because eql does not work on strings in the way that would be necessary for it to work. (eql "a" "a") => nil Is there a way to do it?

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  • Macro and array crossing

    - by Thomas
    I am having a problem with a lisp macro. I would like to create a macro which generate a switch case according to an array. Here is the code to generate the switch-case: (defun split-elem(val) `(,(car val) ',(cdr val))) (defmacro generate-switch-case (var opts) `(case ,var ,(mapcar #'split-elem opts))) I can use it with a code like this: (generate-switch-case onevar ((a . A) (b . B))) But when I try to do something like this: (defparameter *operators* '((+ . OPERATOR-PLUS) (- . OPERATOR-MINUS) (/ . OPERATOR-DIVIDE) (= . OPERATOR-EQUAL) (* . OPERATOR-MULT))) (defmacro tokenize (data ops) (let ((sym (string->list data))) (mapcan (lambda (x) (generate-switch-case x ops)) sym))) (tokenize data *operators*) I got this error: *** - MAPCAR: A proper list must not end with OPS. But I don't understand why. When I print the type of ops I get SYMBOL I was expecting CONS, is it related? Also, for my function tokenize how many times the lambda is evaluated (or the macro expanded)?

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  • Help using Lisp debugger

    - by Joel
    I'm trying understand how to interpret the output of, and use, the Lisp debugger. I've got a pretty simple Backtrace for the evaluation of my function, but I cann't seem to work out how to use it to find out in which Lisp 'form' in my function the exception occurred. I'd appreciate any clues as to what I should be doing, to find the source of the error. I've attached a screen shot (if it's too small to read I can re-post it in parts), with the debug output, the function and the repl (please ignore my very wrong function, I'm just interested in learning how to use the debugger properly). In addition, I hit 'v' on the first frame to go to the source, but this resulted in the error at the bottom of the screen.

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  • When should we use private variables and when should we use properties.

    - by Shantanu Gupta
    In most of the cases we usually creates a private variable and its corresponding public properties and uses them for performing our functionalities. Everyone has different approach like some ppl uses properties every where and some uses private variables within a same class as they are private and opens it to be used by external environment by using properties. Suppose I takes a scenario say insertion in a database. I creates some parameters that need to be initialized. I creates 10 private variables and their corresp public properties which are given as private string name; public string Name { get{return name;} set{name=value;} } and so on. In these cases what should be used internally variables or properties. And in those cases like public string Name { get{return name;} set{name=value>5?5:0;} //or any action can be done. this is just an eg. } In such cases what should be done.

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  • Consolidating values in a junction table

    - by senloe
    I have the following schema: Parcels Segments SegmentsParcels ========= ========== ================= ParcelID SegmentID ParcelID ... Name SegmentID ... id A user of the data wants to consolidate Segments.Names and gave me a list of current Segment.Names mapped to new Segment.Names (all of which currently exist). So now I have this list in a temporary table with the currentID and newID to map to. What I want to do is update the SegmentID in SegmentsParcels based on this map. I could use the statement: update SegmentParcels set segmentID = [newID] from newsegments where segmentID = currentid but this will create some duplicates I have a unique constraint on ParcelID and SegmentID in SegmentParcels. What is the best way to go about this? I considered removing the constraint and then dealing with removing the duplicates (which I did at one point and could probably do again) but I was hoping there was a simpler way.

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  • How to change aif to be able to access 'it' within the macrocall without making 'it' public in the package

    - by Sim
    If you put the aif code presented in onlisp in a package and try to use it in another you run in the problem that packagename:it is not external. (in-package :packagename) (defmacro aif (test-form then-form &optional else-form) ‘(let ((it ,test-form)) (if it ,then-form ,else-form))) wanted call syntax (in-package :otherpackage) (aif (do-stuff) (FORMAT t "~a~%" it) (FORMAT t "just got nil~%")) How can I fix this behavior in code, without making the variable it external in the package declaration and beeing able to access it just by it instead of packagename:it?

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  • Optimizing list comprehension to find pairs of co-prime numbers

    - by user3685422
    Given A,B print the number of pairs (a,b) such that GCD(a,b)=1 and 1<=a<=A and 1<=b<=B. Here is my answer: return len([(x,y) for x in range(1,A+1) for y in range(1,B+1) if gcd(x,y) == 1]) My answer works fine for small ranges but takes enough time if the range is increased. such as 1 <= A <= 10^5 1 <= B <= 10^5 is there a better way to write this or can this be optimized?

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  • Reducing unnecessary same values in Class member variables ....

    - by Freshblood
    class A { public int a; public int c; } i will create 10 instances from A.Then i will create 15 instances from A again... go on. first 10 instance will have same value for a variable and next 15 instances will have again same value for a.But I don't mean that both group has same values for a .Problem is create same a value 10 times in first group and 15 times in second group on memory unnecessary. What would be Best solution or solutions for reduce unnecessary datas in this situation?

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  • When did the idea of macros (user-defined code transformation) appear?

    - by Jay
    I have read McCarthy's 1960 paper on LISP and found no reference to anything that's similar to user-defined macros or normal order evaluation. I was wondering when marcos first appeared in programming language history (and also in Lisp history): When was the idea of user-defined code transformation (before interpretation or compilation) first described (theoretically)? What was the first programming language implementation to have Lisp-like macros (by "Lisp-like" I mean "using a readable Turing-complete language to do code-transformation")? (including non-Lisps -- Forth for example is quite old, but I'm not sure if the first Forth implementation already had "IMMEDIATE") What was the first Lisp dialect to have macros? Thank you!

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  • When should we use private variables and when should we use properties. Do Backing Fields should be

    - by Shantanu Gupta
    In most of the cases we usually creates a private variable and its corresponding public properties and uses them for performing our functionalities. Everyone has different approach like some people uses properties every where and some uses private variables within a same class as they are private and opens it to be used by external environment by using properties. Suppose I takes a scenario say insertion in a database. I creates some parameters that need to be initialized. I creates 10 private variables and their corresp public properties which are given as private string name; public string Name { get{return name;} set{name=value;} } and so on. In these cases mentioned above, what should be used internal variables or properties. And in those cases like public string Name { get{return name;} set{name=value>5?5:0;} //or any action can be done. this is just an eg. } In such cases what should be done.

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  • CLIM tutorial, where?

    - by krzysz00
    I am thinking of using McClim for an application, where can I find a tutorial that covers buttons, keyboard/mouse I/O, drawing images, etc. STFW for mcclim tutorial and clim tutorial didn't help much. Any pointers? If such a tutorial doesn't exist, please point that out and I';; try to RTFM (maybe eventually write such a tutoriial)

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  • Slime: frame-source-location not implemented / is my sldb Backtrace output normal?

    - by Joel
    I'm debugging my Lisp code in Slime. When the debugger generates the Backtrace it's my understanting that I can hit 'v' on a frame to take me to the source. When I do this on the first (0 index) frame (or indeed any frame) I get frame-source-location not implemented Is this expected, am I missing anything? Edit1: In addition every single frame has "No Locals", is this to be expected too? Edit2: In fact, the whole backtrace output is pretty unintelligible. I'm new to Lisp, so I wasn't initially sure if this was expected or not - but I'm attaching a screenshot, hopefully someone can confirm for me if this looks 'normal':

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  • Recursive CTE with alternating tables

    - by SOfanatic
    I've created a SQL fiddle here. Basically, I have 3 tables BaseTable, Files, and a LinkingTable. The Files table has 3 columns: PK, BaseTableId, RecursiveId (ChildId). What I want to do is find all the children given a BaseTableId (i.e., ParentId). The tricky part is that the way the children are found works like this: Take ParentId 1 and use that to look up a FileId in the Files table, then use that FileId to look for a ChildId in the LinkingTable, if that record exists then use the RecursiveId in the LinkingTable to look for the next FileId in the Files table and so on. This is my CTE so far: with CTE as ( select lt.FileId, lt.RecursiveId, 0 as [level], bt.BaseTableId from BaseTable bt join Files f on bt.BaseTableId = f.BaseTableId join LinkingTable lt on f.FileId = lt.FileId where bt.BaseTableId = @Id UNION ALL select rlt.FileId, rlt.RecursiveId, [level] + 1 as [level], CTE.BaseTableId from CTE --??? and this is where I get lost ... ) A correct output for BaseTableId = 1, should be: FileId|RecursiveId|level|BaseTableId 1 1 0 1 3 2 1 1 4 3 2 1

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  • Consecutive calls/evaulations in a form?

    - by Dave
    Hey guys, simple question... Working with XLISP to write a program, but I've seemed to run into a simple fundamental problem that I can't seem to work around: perhaps someone has a quick fix. I'm trying to write an if statement who's then-clause evaluates multiple forms and returns the value of the last. In example: (setq POSITION 'DINING-ROOM) (defun LOOK (DIRECTION ROOM) ... ) (defun SETPOS (ROOM) ... ) (defun WHERE () ... ) (defun MOVE (DIRECTION) (if (not(equal nil (LOOK DIRECTION POSITION))) ; If there is a room in that direction ( ; Then-block: Go to that room. Return where you are. (SETPOS (LOOK DIRECTION ROOM)) (WHERE) ) ( ; Else-block: Return error (list 'CANT 'GO 'THERE) ) ) The logical equivalent intended is: function Move (Direction) { if(Look(Direction, Room) != null) { SetPos(Look(Direction,Room)); return Where(); } else { return "Can't go there"; } } (Apologies for the poor web-formatting.) The problem I have is with: ( (SETPOS (LOOK DIRECTION ROOM)) (WHERE) ) I simply want to return the evaluation of WHERE, but I need to execute the SETPOS function first. XLISP doesn't like the extra parentheses: if I remove the outer set, my WHERE list becomes my else (I don't want that). If I remove the sets around SETPOS and WHERE, it treats WHERE like an argument for SETPOS; I also don't want that. So, how do I simply evaluate the first, then the second and then return the values of the last evaluated?

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  • Optimize INSERT / UPDATE / DELETE operation

    - by clime
    I wonder if the following script can be optimized somehow. It does write a lot to disk because it deletes possibly up-to-date rows and reinserts them. I was thinking about applying something like "insert ... on duplicate key update" and found some possibilities for single-row updates but I don't know how to apply it in the context of INSERT INTO ... SELECT query. CREATE OR REPLACE FUNCTION update_member_search_index() RETURNS VOID AS $$ DECLARE member_content_type_id INTEGER; BEGIN member_content_type_id := (SELECT id FROM django_content_type WHERE app_label='web' AND model='member'); DELETE FROM watson_searchentry WHERE content_type_id = member_content_type_id; INSERT INTO watson_searchentry (engine_slug, content_type_id, object_id, object_id_int, title, description, content, url, meta_encoded) SELECT 'default', member_content_type_id, web_member.id, web_member.id, web_member.name, '', web_user.email||' '||web_member.normalized_name||' '||web_country.name, '', '{}' FROM web_member INNER JOIN web_user ON (web_member.user_id = web_user.id) INNER JOIN web_country ON (web_member.country_id = web_country.id) WHERE web_user.is_active=TRUE; END; $$ LANGUAGE plpgsql; EDIT: Schemas of web_member, watson_searchentry, web_user, web_country: http://pastebin.com/3tRVPPVi. (content_type_id, object_id_int) in watson_searchentry is unique pair in the table but atm the index is not present (there is no use for it). This script should be run at most once a day for full rebuilds of search index.

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  • Call function based off of a string in Lisp

    - by powerj1984
    I am passing in command line arguments to my Lisp program and they are formatted like this when they hit my main function: ("1 1 1" "dot" "2 2 2") I have a dot function and would like to call it directly from the argument, but this isn't possible because something like (funcall (second args)...) receives "dot" and not dot as the function name. I tried variations of this function: (defun remove-quotes (s) (setf (aref s 0) '"")) to no avail, before realizing that the quotes were not really a part of the string. Is there a simple way to do this, or should I just check each string and then call the appropriate function? Thanks!

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  • Cadr of a list involving assoc function

    - by user3619045
    I have looked around on the net and cant find an answer to my query. I would really appreciate if someone could provide a good answer without down rating this post. In Lisp car, cdr are used on data mode like '(whatever here) which makes sense to me. Now, in the book Land of Lisp the author is explaining how to build a text engine and suddenly he uses the following description to make a function. (defun describe-location (location nodes) (cadr (assoc location nodes))) Can I ask why is he doing a cadr on a list and how come it provides a response and not an error? shouldn't it be a data mode i.e with a quote in front of the opening bracket '(whatever here)? and also why is he using assoc as in (assoc location nodes) and not (assoc 'garden *nodes*) Isn't the second correct way to use assoc ? I may be missing the big picture and as such would really appreciate someone explaining these key points please. Many thanks!

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  • what kind of relationship is there between a common wall and the rooms that located next to it?

    - by siamak
    I want to know whats the Relationship between a common wall (that are located In an adjoining room ) and the rooms. As i know the relationship between a room and its walls is Composition not Aggregation (am i right ?) And according to the definition of Composition the contained object can't be shared between two containers, whereas in aggregation it is possible. now i am confused that whats the best modeling approach to represent the relationship between a common wall and the rooms located next to it ? It would be highly Appreciated if you could provide your advices with some code. |--------|--------| Approch1: (wall class ---- room class) /Composition Approach2: wall class ----- room class /Aggregation Approch3: we have a wall class and a Common wall class , Common wall class inherits from wall class adjoining room class ---- (1) Common wall class /Aggregation adjoining room class ---- (6) wall class / composition Approach4: I am a developer not a designer :) so this is my idea : class Room { private wall _firstwall ; private wall _secondtwall; private wall _thirdwall ; private wall _commonwall ; public Room( CommonWall commonwall) { _firstwall=new Wall(); _secondtwall=new Wall(); _thirdwall=new Wall(); _commonwall=commonwall; } } Class CommonWall:Wall { //... } // in somewher : static void main() { Wall _commonWall=new Wall(); Room room1=new Room(_commonWall); Room room2=new Room(_commonWall); Room [] adjacentRoom =new Room[2]{room1,room2}; } Edit 1: I think this is a clear question but just for more clarification : The point of the question is to find out whats the best pattern or approach to model a relationship for an object that is a component of two other objects in the same time. and about my example : waht i mean by a "room" ?,surely i mean an enclosed square room with 4 walls and one door.but in this case one of these walls is a common wall and is shared between two adjacent rooms.

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  • Do you write common pre-conditions for a large number of unit test cases ?

    - by Vinoth Kumar
    I have heard/read writing common pre-conditions for a large number of test cases is a bad thing, since this dependency may cause large number of test cases to fail if something changes . What are your thoughts on it ? If this is so , then what exactly is the purpose of setUp() method in Junit that runs before each test case ? If the same code inside setUp() runs before each test case , why cant it run only once before running all the test cases together ?

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  • UPDATE MANAGER UNABLE TO UPDATE

    - by muguro
    Requires installation of untrusted packages The action would require the installation of packages from not authenticated sources. i get this error every time i try updating. the system shows that it has 466 updates but fails after clicking update more details have this accountsservice apparmor apport apport-gtk apt apt-transport-https apt-utils aptdaemon aptdaemon-data at-spi2-core bamfdaemon base-files bcmwl-kernel-source bind9-host compiz compiz-core compiz-gnome compiz-plugins-default cron cups cups-bsd cups-client cups-common cups-filters cups-ppdc dbus dbus-x11 dconf-gsettings-backend dconf-service desktop-file-utils dmsetup dnsutils empathy empathy-common eog evince evince-common evolution-data-server evolution-data-server-common firefox firefox-globalmenu firefox-gnome-support firefox-locale-en fontconfig fontconfig-config fonts-liberation fonts-opensymbol foomatic-filters gcalctool gdb ghostscript ghostscript-cups ghostscript-x ginn gir1.2-atspi-2.0 gir1.2-dbusmenu-glib-0.4 gir1.2-dbusmenu-gtk-0.4 gir1.2-gst-plugins-base-0.10 gir1.2-gtk-3.0 gir1.2-gtksource-3.0 gir1.2-gudev-1.0 gir1.2-javascriptcoregtk-3.0 gir1.2-launchpad-integration-3.0 gir1.2-pango-1.0 gir1.2-rb-3.0 gir1.2-totem-1.0 gir1.2-ubuntuoneui-3.0 gir1.2-unity-5.0 gir1.2-webkit-3.0 glib-networking glib-networking-common glib-networking-services gnome-accessibility-themes gnome-control-center gnome-control-center-data gnome-desktop3-data gnome-games-data gnome-icon-theme gnome-media gnome-orca gnome-settings-daemon gnome-sudoku gnomine gnupg google-talkplugin gpgv grub-common grub-pc grub-pc-bin grub2-common gstreamer0.10-alsa gstreamer0.10-plugins-base gstreamer0.10-plugins-base-apps gstreamer0.10-x gvfs gvfs-backends gvfs-bin gvfs-common gvfs-daemons gvfs-fuse gvfs-libs gwibber gwibber-service gwibber-service-facebook gwibber-service-identica gwibber-service-twitter hdparm hplip hplip-data indicator-sound initscripts isc-dhcp-client isc-dhcp-common jockey-common jockey-gtk krb5-locales landscape-client-ui-install language-pack-en language-pack-en-base language-pack-gnome-en language-pack-gnome-en-base launchpad-integration libaccountsservice0 libapt-inst1.4 libapt-pkg4.12 libart-2.0-2 libasound2 libatspi2.0-0 libbamf0 libbamf3-0 libbind9-80 libc-bin libc-dev-bin libc6 libc6-dev libcairo-gobject2 libcairo2

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  • Is it common practice to hire third parties to do code reviews for contractors?

    - by blueberryfields
    I recently observed some contract offers which included a "code review by third party" clause - the contract would not pay out fully until the code review was completed and it received a pass. I was surprised, especially considering that these were fairly simple, and small-scale contracts (churning out vanity apps for the iPhone). Is this kind of third-party code review a common thing to run into when contracting out as a programmer?

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  • What common programming problems are best solved by using prototypes and closures?

    - by vemv
    As much as I understand both concepts, I can't see how can I take advantage of JavaScript's closures and prototypes aside from using them for creating instantiable and/or encapsulated class-like blocks (which seems more of a workaround than an asset to me) Other JS features such as functions-as-values or logical evaluation of non-booleans are much easier to fall in love with... What common programming problems are best solved by using propotypal inheritance and closures?

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  • Microsoft sort Kinect Common Bridge, un wrapper open source du SDK Kinect pour contrôler ses modèles 3D avec le corps comme dans Minority Report

    Microsoft sort Kinect Common Bridge un wrapper open source du SDK de Kinect pour contrôler ses modèles 3D avec le corps comme dans Minority ReportConçue au départ pour améliorer l'expérience de jeu des possesseurs de la xBox 360, les horizons de la caméra Kinect se sont élargis avec le temps. En effet, elle est également utilisée dans de nombreux projets qui n'ont rien à voir avec les jeux vidéo. C'est notamment le cas de son utilisation par une équipe chinoise pour transformer le langage des signes...

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