logo
down
shadow

Antlr4 inconsistent tokenizing


Antlr4 inconsistent tokenizing

By : AssemberFriend
Date : November 20 2020, 01:01 AM
seems to work fine Assuming external_data_source_Expression contains the keyword AS, I would make a more specific rule of what external_data_source_Expression really means. The parser rule below should get you any number of columns and should handle the alias just fine. The capitalized rules below are the lexer rules. I didn't define what they all mean, but I suppose you can match them all to a string.
code :
select_from_external_statement:
  SELECT_KEYWORD external_data_source_Expression FROM_KEYWORD external_data_source_definition ;

external_data_source_definition:
  EXTERNAL_SERVER '.' SCHEMA '.' TABLE ;

external_data_source_Expression: 
  column_with_alias (',' column_with_alias)* ;

column_with_alias:
  COLUMN AS_KEYWORD ALIAS ;

SELECT_KEYWORD: 
  'SELECT' ;

FROM_KEYWORD:
  'FROM' ;

AS_KEYWORD: 
  'AS' ;


Share : facebook icon twitter icon
ANTLR4 Tokenizing a Huge Set of Keywords

ANTLR4 Tokenizing a Huge Set of Keywords


By : Krina Chudasama
Date : March 29 2020, 07:55 AM
wish of those help If you want each keyword to have its own token type, you can do the following:
code :
tokens {
    Keyword1,
    Keyword2,
    ...
}
private static final Map<String, Integer> KEYWORDS =
    new HashMap<String, Integer>();
static {
    KEYWORDS.put("keyword1", MyLanguageParser.Keyword1);
    KEYWORDS.put("keyword2", MyLanguageParser.Keyword2);
    ...
}

public static int getKeywordOrIdentifierType(String text) {
     Integer type = KEYWORDS.get(text);
     if (type == null) {
         return MyLanguageParser.Identifier;
     }

     return type;
}
Identifier
    :   [a-zA-Z_] [a-zA-Z0-9_]*
        {_type = MyLanguageKeywords.getKeywordOrIdentifierType(getText());}
    ;
Curbing ANTLR4 greediness (Building ANTLR4 Grammar for existing DSL)

Curbing ANTLR4 greediness (Building ANTLR4 Grammar for existing DSL)


By : Ben Danielmeier
Date : March 29 2020, 07:55 AM
wish helps you Instead of using .*? in your parser rules, try using ~'}'* to ensure that those rules won't try to read past the end of the rule.
Also, you skip whitespace in your lexer but use CHAR+ and DIGIT+ in your parser rules. This means the following are equivalent:
code :
true  in other cases
true  in  other cases
ID : CHAR+;
INT : DIGIT+;
Inconsistent token handling in ANTLR4

Inconsistent token handling in ANTLR4


By : James Fitzy
Date : March 29 2020, 07:55 AM
should help you out The ANTLR4 book references a multi-mode example , One of the following is happening:
code :
OPEN  : '«' -> mode(ISLAND) ;
Antlr4 simple tokenizing failing

Antlr4 simple tokenizing failing


By : ye1088
Date : March 29 2020, 07:55 AM
it fixes the issue I have the following grammar to lex/parse a string, all i am wanting at this point is to tokenize by spaces : , With the posted grammar I don't have that error, but :
code :
$ a4 MyItems_op.g4 
warning(180): MyItems_op.g4:5:13: chars "'" used multiple times in set [' ']
$ javac M*.java
$ grun MyItems_op theseItems -tokens -diagnostics input.text
[@0,0:0='V',<FIELDTEXT>,1:0]
[@1,1:1='3',<FIELDTEXT>,1:1]
[@2,2:2=' ',<' '>,1:2]
[@3,3:3='A',<FIELDTEXT>,1:3]
[@4,4:4='G',<FIELDTEXT>,1:4]
[@5,5:5='L',<FIELDTEXT>,1:5]
...
FIELDTEXT : ~[' ']  ;
grammar MyItems;

theseItems
@init {System.out.println("MyItems last update 0030");}
    :   item (SPACE item)*
    ;

item
    :   FIELDTEXT
    ;

SPACE     : ' ' ;
FIELDTEXT : ~[ \r\n]+ ;

NL  : [\r\n]+ -> skip ;        
$ alias
alias a4='java -jar /usr/local/lib/antlr-4.6-complete.jar'
$ a4 MyItems.g4 
$ javac M*.java
$ grun MyItems theseItems -tokens -diagnostics input.text 
[@0,0:1='V3',<FIELDTEXT>,1:0]
[@1,2:2=' ',<' '>,1:2]
[@2,3:5='AGL',<FIELDTEXT>,1:3]
[@3,6:6=' ',<' '>,1:6]
[@4,7:10='V445',<FIELDTEXT>,1:7]
[@5,12:11='<EOF>',<EOF>,2:0]
MyItems last update 0030
$ hexdump -C input.text 
00000000  56 33 20 41 47 4c 20 56  34 34 35 0a              |V3 AGL V445.|
0000000c
Tokenizing scientific notation in Antlr4 Lexer

Tokenizing scientific notation in Antlr4 Lexer


By : D4vid99
Date : March 29 2020, 07:55 AM
Hope this helps A vastly simplified version of my lexer rules (within a bigger grammar) are something like the following: , My recommendations are:
Related Posts Related Posts :
  • Looking for simplest option to render Razor cshtml pages in a console application without any web server
  • Evaluating variables at a specific time in Modelica
  • When I run the Application, only "web" engine is running in GlassFish. "webservices" is not started
  • How To Set MIME Type Of Google Drive File
  • Remove Missing Values in Weka
  • Reloading a UICollectionView using reloadData method returns immediately before reloading data
  • carrot2 - can I cluster documents from a folder?
  • StreamSocket has no Close Implementation in C#
  • Rails, Foundation 4, Respond.js not working properly in IE8
  • How can i create imagesurface from cairo xlib's Graphics Context using cairo and x11 Api's?
  • CKEditor "overflow: scroll" on parent causes toolbar to freeze at initial position
  • Differences between components and controls in ENYO
  • Photoshop making isometric?
  • Does Intel IPP 8.0 support in-place operations?
  • What is Object dictionary in CANOpen?
  • Example of orbBasic Indexed User Variables
  • convert to ABSOLUTE in logback
  • How to conditionally download file using p:fileDownload
  • Error on pod install
  • Set HTTP GET Parameters in Finagle
  • different attack that uses sql injection
  • How can I change my xampp username not as 'root'
  • AMQP Content header payload structure
  • Apache POI formula evaluation not working for Excel IF
  • How can I trace RESTEasy's dispatch?
  • Map Freezes on iOS 7 with Google Maps SDK 1.4
  • Comparing lists, is the subset list within the first list
  • Non-ascii character highlight in Sublime Text 2
  • Installing Magit in Aquamacs
  • Receiving error - System.Net.Mail.SmtpException: 4.3.2 try again later
  • Coreaudio render callback in monotouch
  • The command 'yarn --v' also initiates 'yarn install' and installs packages automatically. Why is this happening?
  • save multiple matches in a list (grep or awk)
  • Can a number register be used in a groff request?
  • Mapping FAQ with RASA for large dataset (2000+)
  • Fragment not receiving LiveData updates after remove + add
  • FitText.js makes text bigger rather than smaller
  • ARM - Implementing stack with load/store multiple register values
  • How to check if a ChromeCast Session is already in progress
  • ngForm inside a Carousel Slide in UI Bootstrap not working
  • Clearing attributes in Tritium
  • "vagrant up" failing: Vagrant VM failed to remain in the running state
  • ftsearch returning empty docs
  • What are the advantages of setting "hive.exec.parallel" to false in Hive ?
  • Creating a root certificate in FiddlerCore
  • How to access app.config in a blueprint?
  • DB2 RECORDSET table name converted to uppercase
  • Resizing the superview according to the subviews
  • IExpress - Disable Compression
  • Getting InvalidProtocolBufferException while running oozie job
  • What are the differences between Play run and start?
  • How can I share props in ReasonReact?
  • Task.Delay is skipped
  • Parsley.js Password Confirm doesn‘t work
  • How to get all registred 'browser:resource' in Plone
  • Overriding page_list controller inside a package in Concrete5.6.1.2
  • Robolectric 2.x - dependent jars are downloading while running the tests
  • Setting Flyout to Main Frame Navigation(Windows 8.1 app store)
  • Build project - Nuget Error
  • How to recover admin password for SonarQube
  • shadow
    Privacy Policy - Terms - Contact Us © ourworld-yourmove.org