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  • How to get lookahead symbol when constructing LR(1) NFA for parser?

    - by greenoldman
    I am reading an explanation (awesome "Parsing Techniques" by D.Grune and C.J.H.Jacobs; p.292 in the 2nd edition) about how to construct an LR(1) parser, and I am at the stage of building the initial NFA. What I don't understand is how to get/compute a lookahead symbol. Here is the example from the book, the grammar: S -> E E -> E - T E -> T T -> ( E ) T -> n n is terminal. The "weird" transitions for me are is the sequence: 1) S -> . E eof 2) E -> . E - T eof 3) E -> . E - T - 4) E -> E . - T - 5) E -> E - . T - (Note: In the above table, the state numbers are in front and the lookahead symbol is at the end.) What puzzles me is that transition from (4) to (5) means reading - token, right? So how is it that - is still a lookahead symbol and even more important why is it that eof is no longer a lookahead symbol? After all in an input such as n - n eof there is only one - symbol. My naive thinking tells me (5) should be written as: 5) E -> E - . T - eof And another thing -- n is terminal. Why it is not used at all as a lookahead symbol? I mean -- we expect to see - or (, it is ok, but lack of n means we are sure it won't appear in input? Update: after more reading I am only more confused ;-) I.e. what is really a lookahead? Because I see such state as (p.292, 2nd column, 2nd row): E -> E . - T eof Lookahead says eof but the incoming input says -. Isn't it a contradiction? And it is not only in this book.

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  • Cannot Add Particular Word to Dictionary

    - by WCWedin
    I am trying to add a particular word to my custom dictionary using Word 2007. (The word happens to be "deserialized".) When I right-click on the word and click Add to Dictionary, the red underline does not go away. When I use the Spelling & Grammar tool from the Review tab on the ribbon, it will stop on that word; clicking the Add to Dictionary button has no effect. Oddly, I am able to add other words to the custom dictionary without a problem. I recently added "deserializes", for instance. I have only encountered this problem with that one particular word. Does anyone know what might be wrong and how I might fix it? Clarifications My document and all its content is set to English (United States). My custom dictionary is set to apply to All Languages, which is the default value. "Serialize" is in the US English default dictionary, but "deserialize" and its various forms is not.

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  • Hibernate Exception, what wrong ? [[Exception in thread "main" org.hibernate.InvalidMappingException

    - by user195970
    I use netbean 6.7.1 to write "hello world" witch hibernate, but I get some errors, plz help me, thank you very much. my exception init: deps-module-jar: deps-ear-jar: deps-jar: Copying 1 file to F:\Documents and Settings\My Dropbox\DropboxNetBeanProjects\loginspring\build\web\WEB-INF\classes compile-single: run-main: Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Environment <clinit> INFO: Hibernate 3.2.5 Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Environment <clinit> INFO: hibernate.properties not found Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Environment buildBytecodeProvider INFO: Bytecode provider name : cglib Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Environment <clinit> INFO: using JDK 1.4 java.sql.Timestamp handling Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Configuration configure INFO: configuring from resource: /hibernate.cfg.xml Oct 25, 2009 2:44:05 AM org.hibernate.cfg.Configuration getConfigurationInputStream INFO: Configuration resource: /hibernate.cfg.xml Oct 25, 2009 2:44:06 AM org.hibernate.cfg.Configuration addResource INFO: Reading mappings from resource : hibernate/Tbluser.hbm.xml Oct 25, 2009 2:44:06 AM org.hibernate.util.XMLHelper$ErrorLogger error SEVERE: Error parsing XML: XML InputStream(1) Document is invalid: no grammar found. Oct 25, 2009 2:44:06 AM org.hibernate.util.XMLHelper$ErrorLogger error SEVERE: Error parsing XML: XML InputStream(1) Document root element "hibernate-mapping", must match DOCTYPE root "null". Exception in thread "main" org.hibernate.InvalidMappingException: Could not parse mapping document from resource hibernate/Tbluser.hbm.xml at org.hibernate.cfg.Configuration.addResource(Configuration.java:569) at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1587) at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1555) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1534) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1508) at org.hibernate.cfg.Configuration.configure(Configuration.java:1428) at org.hibernate.cfg.Configuration.configure(Configuration.java:1414) at hibernate.CreateTest.main(CreateTest.java:22) Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from invalid mapping at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:502) at org.hibernate.cfg.Configuration.addResource(Configuration.java:566) ... 7 more Caused by: org.xml.sax.SAXParseException: Document is invalid: no grammar found. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:250) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:626) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3095) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:921) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205) at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522) at org.dom4j.io.SAXReader.read(SAXReader.java:465) at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:499) ... 8 more Java Result: 1 BUILD SUCCESSFUL (total time: 1 second) hibernate.cfg.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate</property> <property name="hibernate.connection.username">root</property> </session-factory> </hibernate-configuration> Tbluser.hbm.xml <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated Oct 25, 2009 2:37:30 AM by Hibernate Tools 3.2.1.GA --> <hibernate-mapping> <class name="hibernate.Tbluser" table="tbluser" catalog="hibernate"> <id name="userId" type="java.lang.Integer"> <column name="userID" /> <generator class="identity" /> </id> <property name="username" type="string"> <column name="username" length="50" /> </property> <property name="password" type="string"> <column name="password" length="50" /> </property> <property name="email" type="string"> <column name="email" length="50" /> </property> <property name="phone" type="string"> <column name="phone" length="50" /> </property> <property name="groupId" type="java.lang.Integer"> <column name="groupID" /> </property> </class> </hibernate-mapping> Tbluser.java package hibernate; // Generated Oct 25, 2009 2:37:30 AM by Hibernate Tools 3.2.1.GA /** * Tbluser generated by hbm2java */ public class Tbluser implements java.io.Serializable { private Integer userId; private String username; private String password; private String email; private String phone; private Integer groupId; public Tbluser() { } public Tbluser(String username, String password, String email, String phone, Integer groupId) { this.username = username; this.password = password; this.email = email; this.phone = phone; this.groupId = groupId; } public Integer getUserId() { return this.userId; } public void setUserId(Integer userId) { this.userId = userId; } public String getUsername() { return this.username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return this.password; } public void setPassword(String password) { this.password = password; } public String getEmail() { return this.email; } public void setEmail(String email) { this.email = email; } public String getPhone() { return this.phone; } public void setPhone(String phone) { this.phone = phone; } public Integer getGroupId() { return this.groupId; } public void setGroupId(Integer groupId) { this.groupId = groupId; } }

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  • Need help regarding one LALR(1) parsing.

    - by AppleGrew
    I am trying to parse a context-free language, called Context Free Art. I have created its parser in Javascript using a YACC-like JS LALR(1) parser generator JSCC. Take the example of following CFA (Context Free Art) code. This code is a valid CFA. startshape A rule A { CIRCLE { s 1} } Notice the A and s in above. s is a command to scale the CIRCLE, but A is just a name of this rule. In the language's grammar I have set s as token SCALE and A comes under token STRING (I have a regular expression to match string and it is at the bottom of of all tokens). This works fine, but in the below case it breaks. startshape s rule s { CIRCLE { s 1} } This too is a perfectly valid code, but since my parser marks s after rule as SCALE token so it errors out saying that it was expecting STRING. Now my question is, if there is any way to re-write the production rules of the parser to account for this? The related production rule is:- rule: RULE STRING '{' buncha_replacements '}' [* rule(%2, 1) *] | RULE STRING RATIONAL '{' buncha_replacements '}' [* rule(%2, 1*%3) *] ; One simple solution I can think of is create a copy of above rule with STRING replaced by SCALE, but this is just one of the many similar rules which would need such fixing. Furthermore there are many other terminals which can get matched to STRING. So that means way too many rules!

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  • Parsing an arithmetic expression and building a tree from it in Java

    - by ChocolateBear
    Hi, I needed some help with creating custom trees given an arithmetic expression. Say, for example, you input this arithmetic expression: (5+2)*7 The result tree should look like: * / \ + 7 / \ 5 2 I have some custom classes to represent the different types of nodes, i.e. PlusOp, LeafInt, etc. I don't need to evaluate the expression, just create the tree, so I can perform other functions on it later. Additionally, the negative operator '-' can only have one child, and to represent '5-2', you must input it as 5 + (-2). Some validation on the expression would be required to ensure each type of operator has the correct the no. of arguments/children, each opening bracket is accompanied by a closing bracket. Also, I should probably mention my friend has already written code which converts the input string into a stack of tokens, if that's going to be helpful for this. I'd appreciate any help at all. Thanks :) (I read that you can write a grammar and use antlr/JavaCC, etc. to create the parse tree, but I'm not familiar with these tools or with writing grammars, so if that's your solution, I'd be grateful if you could provide some helpful tutorials/links for them.)

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  • Big problem with regular expression in Lex (lexical analyzer)

    - by Nazgulled
    Hi, I have some content like this: author = "Marjan Mernik and Viljem Zumer", title = "Implementation of multiple attribute grammar inheritance in the tool LISA", year = 1999 author = "Manfred Broy and Martin Wirsing", title = "Generalized Heterogeneous Algebras and Partial Interpretations", year = 1983 author = "Ikuo Nakata and Masataka Sassa", title = "L-Attributed LL(1)-Grammars are LR-Attributed", journal = "Information Processing Letters" And I need to catch everything between double quotes for title. My first try was this: ^(" "|\t)+"title"" "*=" "*"\"".+"\"," Which catches the first example, but not the other two. The other have multiple lines and that's the problem. I though about changing to something with \n somewhere to allow multiple lines, like this: ^(" "|\t)+"title"" "*=" "*"\""(.|\n)+"\"," But this doesn't help, instead, it catches everything. Than I though, "what I want is between double quotes, what if I catch everything until I find another " followed by ,? This way I could know if I was at the end of the title or not, no matter the number of lines, like this: ^(" "|\t)+"title"" "*=" "*"\""[^"\""]+"," But this has another problem... The example above doesn't have it, but the double quote symbol (") can be in between the title declaration. For instance: title = "aaaaaaa \"X bbbbbb", And yes, it will always be preceded by a backslash (\). Any suggestions to fix this regexp?

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  • Parsing some particular statements with antlr3 in C target

    - by JCD
    Hello all! I have some questions about antlr3 with tree grammar in C target. I have almost done my interpretor (functions, variables, boolean and math expressions ok) and i have kept the most difficult statements for the end (like if, switch, etc.) 1) I would like interpreting a simple loop statement: repeat: ^(REPEAT DIGIT stmt); I've seen many examples but nothing about the tree walker (only a topic here with the macros MARK() / REWIND(m) + @init / @after but not working (i've antlr errors: "unexpected node at offset 0")). How can i interpret this statement in C? 2) Same question with a simple if statement: if: ^(IF condition stmt elseifstmt* elsestmt?); The problem is to skip the statement if the condition is false and test the other elseif/else statements. 3) I have some statements which can stop the script (like "break" or "exit"). How can i interrupt the tree walker and skip the following tokens? 4) When a lexer or parser error is detected, antlr returns an error. But i would like to make my homemade error messages. How can i have the line number where parser crashed? Ask me if you want more details. Thanks you very much (and i apologize for my poor english)

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  • Problem calling std::max

    - by Eric
    I compiled my bison-generated files in Visual Studio and got these errors: ...\position.hh(83): error C2589: '(' : illegal token on right side of '::' ...\position.hh(83): error C2059: syntax error : '::' ...\position.hh(83): error C2589: '(' : illegal token on right side of '::' ...\position.hh(83): error C2059: syntax error : '::' The corresponding code is: inline void columns (int count = 1) { column = std::max (1u, column + count); } I think the problem is with std::max; if I change std::max to equivalent code then there is no problem anymore, but is there a better solution instead of changing the generated code? Here is the bison file I wrote: // // bison.yy // %skeleton "lalr1.cc" %require "2.4.2" %defines %define parser_class_name "cmd_parser" %locations %debug %error-verbose %code requires { class ParserDriver; } %parse-param { ParserDriver& driver } %lex-param { ParserDriver& driver } %union { struct ast *a; double d; struct symbol *s; struct symlist *sl; int fn; } %code { #include "helper_func.h" #include "ParserDriver.h" std::string error_msg = ""; } %token <d> NUMBER %token <s> NAME %token <fn> FUNC %token EOL %token IF THEN ELSE WHILE DO LET %token SYM_TABLE_OVERFLOW %token UNKNOWN_CHARACTER %nonassoc <fn> CMP %right '=' %left '+' '-' %left '*' '/' %nonassoc '|' UMINUS %type <a> exp stmt list explist %type <sl> symlist %{ extern int yylex(yy::cmd_parser::semantic_type *yylval, yy::cmd_parser::location_type* yylloc); %} %start calclist %% ... grammar rules ...

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  • executing stored procedure from Spring-Hibernate using Annotations

    - by HanuAthena
    I'm trying to execute a simple stored procedure with Spring/Hibernate using Annotations. Here are my code snippets: DAO class: public class UserDAO extends HibernateDaoSupport { public List selectUsers(final String eid){ return (List) getHibernateTemplate().execute(new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException, SQLException { Query q = session.getNamedQuery("SP_APPL_USER"); System.out.println(q); q.setString("eid", eid); return q.list(); } }); } } my entity class: @Entity @Table(name = "APPL_USER") @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorFormula(value = "SUBSCRIBER_IND") @DiscriminatorValue("N") @NamedQuery(name = "req.all", query = "select n from Requestor n") @org.hibernate.annotations.NamedNativeQuery(name = "SP_APPL_USER", query = "call SP_APPL_USER(?, :eid)", callable = true, readOnly = true, resultClass = Requestor.class) public class Requestor { @Id @Column(name = "EMPL_ID") public String getEmpid() { return empid; } public void setEmpid(String empid) { this.empid = empid; } @Column(name = "EMPL_FRST_NM") public String getFirstname() { return firstname; } ... } public class Test { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext( "applicationContext.xml"); APFUser user = (APFUser)ctx.getBean("apfUser"); List selectUsers = user.getUserDAO().selectUsers("EMP456"); System.out.println(selectUsers); } } and the stored procedure: create or replace PROCEDURE SP_APPL_USER (p_cursor out sys_refcursor, eid in varchar2) as empId varchar2(8); fname varchar2(50); lname varchar2(50); begin empId := null; fname := null; lname := null; open p_cursor for select l.EMPL_ID, l.EMPL_FRST_NM, l.EMPL_LST_NM into empId, fname, lname from APPL_USER l where l.EMPL_ID = eid; end; If i enter invalid EID, its returning empty list which is OK. But when record is there, following exception is thrown: Exception in thread "main" org.springframework.jdbc.BadSqlGrammarException: Hibernate operation: could not execute query; bad SQL grammar [call SP_APPL_USER(?, ?)]; nested exception is java.sql.SQLException: Invalid column name Do I need to modify the entity(Requestor.class) ? How will the REFCURSOR be converted to the List? The stored procedure is expected to return more than one record.

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  • Programming Technique: How to create a simple card game

    - by Shyam
    Hi, As I am learning the Ruby language, I am getting closer to actual programming. So I was thinking of creating a simple card game. My question isn't Ruby orientated, but I do know want to learn how to solve this problem with a genuine OOP approach. In my card game I want to have four players. Using a standard deck with 52 cards, no jokers/wildcards. In the game I won't use the Ace as a dual card, it is always the highest card. So, the programming problems I wonder about are the following: How can I sort/randomize the deck of cards? There are four types, each having 13 values. Eventually there can be only unique values, so picking random values could generate duplicates. How can I implement a simple AI? As there are tons of card games, someone would have figured this part out already, so references would be great. I am a truly Ruby nuby, and my goal here is to learn to solve problems, so pseudo code would be great, just to understand how to solve the problem programmatically. I apologize for my grammar and writing style if it's unclear, for it is not my native language. Also pointers to sites where such challenges are explained, would be a great resource! Thank you for your comments, answers and feedback!

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  • errors when using c++ bison ---- in the file position.hh

    - by Eric
    firstly I'm not good at English so forgive me. I compile my program with the bison generated files in visual studio and get these errors: ...\position.hh(83): error C2589: '(' : illegal token on right side of '::' ...\position.hh(83): error C2059: syntax error : '::' ...\position.hh(83): error C2589: '(' : illegal token on right side of '::' ...\position.hh(83): error C2059: syntax error : '::' and the corresponding code is: inline void columns (int count = 1) { column = std::max (1u, column + count); } I think the problem is with std::max. If I change std::max to equivalent code then there is problem anymore, but is there a better solution instead of changing the generated code? here is the *.yy file I wrote. // // bison.yy // %skeleton "lalr1.cc" %require "2.4.2" %defines %define parser_class_name "cmd_parser" %locations %debug %error-verbose %code requires { class ParserDriver; } %parse-param { ParserDriver& driver } %lex-param { ParserDriver& driver } %union { struct ast *a; double d; struct symbol *s; struct symlist *sl; int fn; } %code { #include "helper_func.h" #include "ParserDriver.h" std::string error_msg = ""; } %token <d> NUMBER %token <s> NAME %token <fn> FUNC %token EOL %token IF THEN ELSE WHILE DO LET %token SYM_TABLE_OVERFLOW %token UNKNOWN_CHARACTER %nonassoc <fn> CMP %right '=' %left '+' '-' %left '*' '/' %nonassoc '|' UMINUS %type <a> exp stmt list explist %type <sl> symlist %{ extern int yylex(yy::cmd_parser::semantic_type *yylval, yy::cmd_parser::location_type* yylloc); %} %start calclist %% ... grammar rules ...

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  • Can Haskell's Parsec library be used to implement a recursive descent parser with backup?

    - by Thor Thurn
    I've been considering using Haskell's Parsec parsing library to parse a subset of Java as a recursive descent parser as an alternative to more traditional parser-generator solutions like Happy. Parsec seems very easy to use, and parse speed is definitely not a factor for me. I'm wondering, though, if it's possible to implement "backup" with Parsec, a technique which finds the correct production to use by trying each one in turn. For a simple example, consider the very start of the JLS Java grammar: Literal: IntegerLiteral FloatingPointLiteral I'd like a way to not have to figure out how I should order these two rules to get the parse to succeed. As it stands, a naive implementation like this: literal = do { x <- try (do { v <- integer; return (IntLiteral v)}) <|> (do { v <- float; return (FPLiteral v)}); return(Literal x) } Will not work... inputs like "15.2" will cause the integer parser to succeed first, and then the whole thing will choke on the "." symbol. In this case, of course, it's obvious that you can solve the problem by re-ordering the two productions. In the general case, though, finding things like this is going to be a nightmare, and it's very likely that I'll miss some cases. Ideally, I'd like a way to have Parsec figure out stuff like this for me. Is this possible, or am I simply trying to do too much with the library? The Parsec documentation claims that it can "parse context-sensitive, infinite look-ahead grammars", so it seems like something like I should be able to do something here.

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  • Writing language converter in ANTLR

    - by Stefan
    I'm writing a converter between some dialects of the same programming language. I've found a grammar on the net - it's complex and handles all the cases. Now I'm trying to write the appropriate actions. Most of the input is just going to be rewritten to output. What I need to do is parse function calls, do my magic (rename function, reorder arguments, etc) and write it. I'm using AST as output. When I come across a function call, I build a custom object structure (from classes defined in my target language), call the appropriate function and I have a string that represents the transformed function that I want to get. The problem is, what I'm supposed to do with that string? I'd like to replace the .text attribute of the enclosing rule, but setText() is only available on lexer rules and the rule's .text attribute is read-only. How to solve this problem? program : statement_list { output = $statement_list.text; } ; //... statement : expression_statement // ... ; expression_statement : function_call // ... ; function_call : ID '(' { /* build the object, assign name */ Function function = new Function(); //... } ( arg1 = expression { /* add first parameter */ } ( ',' arg2 = expression { /* add the rest of parameters */ } )* )? ')' { /* convert the function call */ string converted = Tools.Convert(function); // $setText(converted); // doesn't work // $functionCall.text = converted; // doesn't work } ;

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  • Why linking doesn't work in my Xtext-based DSL?

    - by reprogrammer
    The following is the Xtext grammar for my DSL. Model: variableTypes=VariableTypes predicateTypes=PredicateTypes variableDeclarations= VariableDeclarations rules=Rules; VariableType: name=ID; VariableTypes: 'var types' (variableTypes+=VariableType)+; PredicateTypes: 'predicate types' (predicateTypes+=PredicateType)+; PredicateType: name=ID '(' (variableTypes+=[VariableType|ID])+ ')'; VariableDeclarations: 'vars' (variableDeclarations+=VariableDeclaration)+; VariableDeclaration: name=ID ':' type=[VariableType|ID]; Rules: 'rules' (rules+=Rule)+; Rule: head=Head ':-' body=Body; Head: predicate=Predicate; Body: (predicates+=Predicate)+; Predicate: predicateType=[PredicateType|ID] '(' (terms+=Term)+ ')'; Term: variable=Variable; Variable: variableDeclaration=[VariableDeclaration|ID]; terminal WS: (' ' | '\t' | '\r' | '\n' | ',')+; And, the following is a program in the above DSL. var types Node predicate types Edge(Node, Node) Path(Node, Node) vars x : Node y : Node z : Node rules Path(x, y) :- Edge(x, y) Path(x, y) :- Path(x, z) Path(z, y) When I used the generated Switch class to traverse the EMF object model corresponding to the above program, I realized that the nodes are not linked together properly. For example, the getPredicateType() method on a Predicate node returns null. Having read the Xtext user's guide, my impression is that the Xtext default linking semantics should work for my DSL. But, for some reason, the AST nodes of my DSL don't get linked together properly. Can anyone help me in diagnosing this problem?

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  • How to set UCS2 in numpy?

    - by mindcorrosive
    I'm trying to build numpy 1.2.1 as a module for a third-party python interpreter (custom-built, py2.4 linux x86_64) so that I can make calls to numpy from within it. Let's call this one interpreter A. The thing is, the system-wide python interpreter (also py2.4, let's call it B) from the vendor is built with --enable-unicode=ucs4, while the custom one is with UCS2. Needless to say, when I try to build a module with B, I get an error when I try to import numpy in A -- it complains about undefined symbol _PyUnicodeUCS4_IsWhiteSpace. I've searched around and apparently there's no way around this but to compile a custom Python interpreter -- which I did (let's call it interpreter C), properly specifying the unicode string length (verifiable through sys.maxunicode). I managed to build numpy with C as well, surprisingly enough, but still the problem persists when I try to import it in interpreter C. Previously, when I built numpy using B, there were no problems when importing it in B, but A would complain. Perhaps there's an option when building numpy to specify the length of Unicode strings to be used, as when configuring Python builds? Or am I doing something else wrong? A few notes: Upgrading to newer versions of python and/or numpy is not an option - interpreter A will stay on this version of the grammar for the foreseeable future. Also, it is not possible to start the interpreter A in standalone mode to build numpy with it, as it needs some other libraries preloaded I know that this whole thing is a mess, but I'd appreciate any help I can get to make this work. If you need more information, please let me know, I'd be happy to oblige. Thanks to everybody for their time in advance.

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  • How would you go about parsing markdown?

    - by John Leidegren
    You can find the syntax here. The thing is, the source that follows with the download is written in perl. Which I have no intentions of honoring. It is riddled with regex and it relies on MD5 hashes to escape certain characters. Something is just wrong about that! I'm about to hard code a parser for markdown and I'm wonder if someone had some experience with this? Edit: If you don't have anything meaningful to say about the actual parsing of markdown, spare me the time. (This might sound harsh, but yes, I'm looking for insight, not a solution i.e. third-party library). To help a bit with the answers, regex are meant to identify patterns! NOT to parse an entire grammar. That people consider doing so is foobar. If you think about markdown, it's fundamentally based around the concept of paragraphs. As such, a reasonable approach might be to split the input into paragraphs. There are many kinds of paragraphs e.g. heading, text, list, blockquote, code. The challenge is thus to identify these paragraphs and in what context they occur. I'll be back with a solution, once I find it's worthy to be shared.

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  • How do I get Bison/YACC to not recognize a command until it parses the whole string?

    - by chucknelson
    I have some bison grammar: input: /* empty */ | input command ; command: builtin | external ; builtin: CD { printf("Changing to home directory...\n"); } | CD WORD printf("Changing to directroy %s\n", $2); } ; I'm wondering how I get Bison to not accept (YYACCEPT?) something as a command until it reads ALL of the input. So I can have all these rules below that use recursion or whatever to build things up, which either results in a valid command or something that's not going to work. One simple test I'm doing with the code above is just entering "cd mydir mydir". Bison parses CD and WORD and goes "hey! this is a command, put it to the top!". Then the next token it finds is just WORD, which has no rule, and then it reports an error. I want it to read the whole line and realize CD WORD WORD is not a rule, and then report an error. I think I'm missing something obvious and would greatly appreciate any help - thanks! Also - I've tried using input command NEWLINE or something similar, but it still pushes CD WORD to the top as a command and then parses the extra WORD separately.

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  • why does this boost::spirit::qi rule not work?

    - by Tobias Langner
    I have a grammar that defines the following rules: constantValue = qi::token(ID_FLOAT) | qi::token(ID_INTEGER); postfixExpression = primaryExpression | (postfixExpression >> qi::token(ID_OPENBRACKET) >> qi::token(ID_INTEGER) >> qi::token(ID_CLOSEBRACKET)) | (postfixExpression >> qi::token(ID_DOT) >> qi::token(ID_IDENTIFIER)); primaryExpression = qi::token(ID_IDENTIFIER) | constantValue | (qi::token(ID_OPENPAREN) >> primaryExpression >> qi::token(ID_CLOSEPAREN)); ges = postfixExpression >> qi::eoi; and I want it to match the following strings: test[1] testident.ident and it should not match test[1.2] testident.5 but it fails to match the first 2 strings. The lexer constructor is as follows: custom_lexer() : identifier("[a-zA-Z_][a-zA-Z0-9_]*") , white_space("[ \\t\\n]+") , integer_value("[1-9][0-9]*") , hex_value("0[xX][0-9a-fA-F]+") , float_value("[0-9]*\\.[0-9]+([eE][+-]?[0-9]+)?") , float_value2("[0-9]+\\.([eE][+-]?[0-9]+)?") , punctuator("&>|\\*\\*|\\*|\\+|-|~|!|\\/|%|<<|>>|<|>|<=|>=|==|!=|\\^|&|\\||\\^\\^|&&|\\|\\||\\?|:|,")// [ ] ( ) . &> ** * + - ~ ! / % << >> < > <= >= == != ^ & | ^^ && || ? : , { using boost::spirit::lex::_start; using boost::spirit::lex::_end; this->self.add (identifier, ID_IDENTIFIER) /*(white_space, ID_WHITESPACE)*/ (integer_value, ID_INTEGER) (hex_value, ID_INTEGER) (float_value, ID_FLOAT) (float_value2, ID_FLOAT) ("\\(", ID_OPENPAREN) ("\\)", ID_CLOSEPAREN) ("\\[", ID_OPENBRACKET) ("\\]", ID_CLOSEBRACKET) ("\\.", ID_DOT) (punctuator, ID_PUNCTUATOR) ; this->self("WS") = white_space; } Why don't I get a match for the mentioned strings? Thank you Tobias

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  • How can I direct edge to get out of the diamond on the right?

    - by Didier Trosset
    I have a simple dot diagram to show how to perform tests. PerformTests; PerformTests<---+ PerformTests -> TestsPassed; | | TestsPassed [shape="diamond"]; v | TestsPassed -> Release [label="Yes"]; TestsPassed | TestsPassed -> FixErrors [label="No"]; Y| N\ | FixErrors -> PerformTests; v FixErrors Release The diagram shows square boxes for all nodes, except TestPassed that has a diamond shape. My issue is here. I'd like the edge that goes outside of the diamond for No to be getting out of the diamond at the right (east) instead of oblique down-right (south-east). What I have What I want ^ ^ / \ / \ < > < >---> \ /\ \ / v \ v I've seen such compass_pt in the dot grammar, but cannot figure out how to use it. I what I want possible, and how to do it?

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  • Translating PHP language file

    - by Cudos
    Hello. I have a language file like this: <?php $lng_imagepath = "images/"; $lng_imageext = "gif"; $lng_characset = "iso-8859-1"; $lng_prefix = "en_"; $lng_tabhome = "Home"; $lng_tabmyavenue = "My Profile"; $lng_tabregister = "Register"; $lng_tabhelp = "Help"; $lng_tabbuybids = "Buy Bids"; ?> When I convert into a .html file and run Google translate it looks like this: Glemt brugernavn eller adgangskode? "; $ lng_invaliddata =" Ugyldig brugernavn og password. "$ lng_accountsuspend =" Din konto er suspenderet af vindetbud.dk. "$ lng_accountdelete =" Din konto er blevet slettet af vindetbud.dk. "$ lng_enterdata = "Angiv brugernavn og adgangskode." $ lng_enterpassword = "Angiv adgangskoden." / / slut login side variabel / / Language variabler for registrering side $ lng_frregistration = "Gratis registrering"; $ lng_vouchermessage = "voucher, indløses mod første auktion du vinder "; $ lng_amazingproducts =" Chancen for at vinde fantastiske produkter til fantastiske priser "; $ lng_registrationdata =" Du kan tilmelde med vindetbud.dk, bedes du udfylde følgende "; $ lng_personalinfo =" Personlige oplysninger "; $ lng_firstname =" Første Name "; $ lng_lastname =" Efternavn "; $ lng_birthdate =" Fødselsdato "; Do you have any clever ideas how to translate the file? P.S. I know that grammar won't be perfect, but it would help alot to use google translate.

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  • How to store an inventory using hashtables?

    - by Harm De Weirdt
    Hello everyone. For an assignment in collego we have to make a script in Perl that allows us to manage an inventory for an e-store. (The example given was Amazon) Users can make orders in a fully text-based environment and the inventory must be updated when an order is completed. Every item in the inventory has 3 to 4 attributes: a product code, a title, a price and for some an amount (MP3's for example do not have this attribute) Since this is my first encounter with Perl, i don't really know how to start. My main problem is how i should "implement" the inventory in the program. One of the functions of the program is searching trough the titles. Another is to make an order, where the user should give a product code. My first idea was a hashtable with the productcode as key. But if i wanted to search in the titles that could be a problem because of this: the hashkey would be something like DVD-123, the information belonging to that key could be "The Green Mask 12" (without the ") where the 12 indicates how many of this DVD are currently in stock. So i'd have to find a way to ignore the 12 in the end. Another solution was to use the title as Hashkey, but that would prove cumbersome too I think. Is there a way to make a hashtable with 2 key's, and when I give only one it returns an array with the other values? (Including the other key and the other information) That way I could use another key depending on what info I need from my inventory. We have to read the default inventory from a txt file looking like this: MP3-72|Lady Gaga - Kiss and Run (Fear of Commitment Monster)|0.99 CD-400|Kings of Leon - Only By The Night|14.50|2 MP3-401|Kings of Leon - Closer|0.85 DVD-144|Live Free or Die Hard|14.99|2 SOFT-864|Windows Vista|49.95 Any help would be appreciated very much :) PS: I am sorry for my bad grammar, English isn't my native language.

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  • Rails: creating a custom data type, to use with generator classes and a bunch of questions related t

    - by Shyam
    Hi, After being productive with Rails for some weeks, I learned some tricks and got some experience with the framework. About 10 days ago, I figured out it is possible to build a custom data type for migrations by adding some code in the Table definition. Also, after learning a bit about floating points (and how evil they are) vs integers, the money gem and other possible solutions, I decided I didn't WANT to use the money gem, but instead try to learn more about programming and finding a solution myself. Some suggestions said that I should be using integers, one for the whole numbers and one for the cents. When playing in script/console, I discovered how easy it is to work with calculations and arrays. But, I am talking to much (and the reason I am, is to give some sufficient background). Right now, while playing with the scaffold generator (yes, I use it, because I like they way I can quickly set up a prototype while I am still researching my objectives), I like to use a DRY method. In my opinion, I should build a custom "object", that can hold two variables (Fixnum), one for the whole, one for the cents. In my big dream, I would be able to do the following: script/generate scaffold Cake name:string description:text cost:mycustom Where mycustom should create two integer columns (one for wholes, one for cents). Right now I could do this by doing: script/generate scaffold Cake name:string description:text cost_w:integer cost_c:integer I had also had an idea that would be creating a "cost model", which would hold two columns of integers and create a cost_id column to my scaffold. But wouldn't that be an extra table that would cause some kind of performance penalty? And wouldn't that be defy the purpose of the Cake model in the first place, because the costs are an attribute of individual Cake entries? The reason why I would want to have such a functionality because I am thinking of having multiple "costs" inside my rails application. Thank you for your feedback, comments and answers! I hope my message got through as understandable, my apologies for incorrect grammar or weird sentences as English is not my native language.

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  • Some languages don't work when using Word 2007 Spellcheck from Interop

    - by Tridus
    I'm using the Word 2007 spellchecker via Interop in a VB.net desktop app. When using the default language (English), it works fine. If I set the language to French via LanguageId, it also works. But if I set it to French (Canadian) (Word.WdLanguageID.wdFrenchCanadian), it doesn't work. There's no error message, it simply runs and says the document contains no errors. I know it does, if I paste the exact same text into Word itself and run it with the French (Canadian) dictionary, it finds errors. Just why that dictionary doesn't work is kind of a mystery to me. Full code below: Public Shared Function SpellCheck(ByVal text As String, ByVal checkGrammar As Boolean) As String ' If there is no data to spell check, then exit sub here. If text.Length = 0 Then Return text End If Dim objWord As Word.Application Dim objTempDoc As Word.Document ' Declare an IDataObject to hold the data returned from the ' clipboard. Dim iData As IDataObject objWord = New Word.Application() objTempDoc = objWord.Documents.Add objWord.Visible = False ' Position Word off the screen...this keeps Word invisible ' throughout. objWord.WindowState = 0 objWord.Top = -3000 ' Copy the contents of the textbox to the clipboard Clipboard.SetDataObject(text) ' With the temporary document, perform either a spell check or a ' complete ' grammar check, based on user selection. With objTempDoc .Content.Paste() .Activate() .Content.LanguageID = Word.WdLanguageID.wdFrenchCanadian If checkGrammar Then .CheckGrammar() Else .CheckSpelling() End If ' After user has made changes, use the clipboard to ' transfer the contents back to the text box .Content.Copy() iData = Clipboard.GetDataObject If iData.GetDataPresent(DataFormats.Text) Then text = CType(iData.GetData(DataFormats.Text), _ String) End If .Saved = True .Close() End With objWord.Quit() Return text End Function

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  • What good open source programs exist for fuzzing popular image file types?

    - by JohnnySoftware
    I am looking for a free, open source, portable fuzzing tool for popular image file types that is written in either Java, Python, or Jython. Ideally, it would accept specifications for the fuzzable fields using some kind of declarative constraints. Non-procedural grammar for specifying constraints are greatly preferred. Otherwise, might as well write them all in Python or whatever. Just specifying ranges of valid values or expressions for them. Ideally, it would support some kind of generative programming to export the fuzzer into various programming languages to suit cases where more customization was required. If it supported a direct-manipulation GUI for controlling parameter values and ranges, that would be nice too. The file formats that should be supported are: GIF JPEG PNG So basically, it should be sort of a toolkit consisting of ready-to-run utility, a framework or library, and be capable of generating the fuzzed files directly as well as from programs it generates. It needs to be simple so that test images can be created quickly. It should have a batch capability for creating a series of images. Creating just one at a time would be too painful. I do not want a hacking tool, just a QA tool. Basically, I just want to address concerns that it is taking too long to get commonplace image rendering/parsing libraries stable and trustworthy.

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  • Is a full html page needed when loading a page with jQuery mobile?

    - by Vincent Hiribarren
    I am currently looking at jQuery mobile and its system of loading web pages with XmlHttpRequest. Thanks to that it is possible to automatically perform transition animations between two pages, for instance. However, something is not clear to me. If I understand correctly, each new page of a jQuery mobile powered website is injected in the DOM of the initial web page. The documentation of jQuery mobile even tells that because of this mechanism, the <title> tag of new webpages are not taken into account. So, in a way, if my initial webpage A.html loads a page B.html, I would tend to think that the webpage B.html does not need to have a full HTML grammar with the <html>, <head> or <body> tags. My page B.html could directly begin with a <div> element. Am I right?Is a full html page needed when loading a HTML page with jQuery mobile?What are the pros and cons about having a webpage with a wrong/truncated HTML syntax (appart that this page should not be accessed directly but through the main page)?

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