antlr3 | 易学教程

What does ^ and ! stand for in ANTLR grammar

阅读更多关于 What does ^ and ! stand for in ANTLR grammar

问题 I was having difficulty figuring out what does ^ and ! stand for in ANTLR grammar terminology. 回答1: Have a look at the ANTLR Cheat Sheet: ! don't include in AST ^ make AST root node And ^ can also be used in rewrite rules: ... -> ^( ... ) . For example, the following two parser rules are equivalent: expression : A '+'^ A ';'! ; and: expression : A '+' A ';' -> ^('+' A A) ; Both create the following AST: + / \ A A In other words: the + is made as root, the two A 's its children, and the ; is

“FOLLOW_set_in_”… is undefined in generated parser

阅读更多关于 “FOLLOW_set_in_”… is undefined in generated parser

问题 I have written a grammar for vaguely Java-like DSL. While there are still some issues with it (it doesn't recognize all the inputs as I would want it to), what concerns me most is that the generated C code is not compilable. I use AntlrWorks 1.5 with Antlr 3.5 (Antlr 4 apparently does not support C target). The problem is with expression rules. I have rules prio14Expression to prio0Expression which handle operator precedence. To problem is at priority 2, which evaluates prefix and postfix

ANTLR3 throws internal error with java.lang.NullPointerException

阅读更多关于 ANTLR3 throws internal error with java.lang.NullPointerException

问题 I tried to use ANTLR3 to build a simple Regexpression parser, but it throws the internal error Here is the Sample.g grammar Sample; options { memoize=true; output=AST; } tokens { RegExp; } RegExpression: '/' (a=~('/' | NL))+ '/' -> ^(RegExp[$RegExpression.start, $RegExpression.text] $a+ ) ; fragment NL: '\n' | '\r'; ANY : . ; I run the command: java -jar antlr-3.5.2-complete.jar -print Sample.g and it gives this: error(10): internal error: Sample.g : java.lang.NullPointerException org.antlr

Including external C library with Xcode

阅读更多关于 Including external C library with Xcode

I have a built C static library (the Antlr 3 C library). It is installed properly and works (i.e., I can run gcc -o parser lexer.c parser.c -lantlr3c just fine). In Xcode, however, I get an error. I've added -lantlr3c in the "other linker flags" build setting. ld: library not found for -lantlr3c Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1 Several other questions I've found here ( 1 , 2 , 3 , 4 ) generally have answers targeting Xcode 3. I'm using Xcode 4.1, in an iOS static library project. I'm currently building the unit test

How Lexer lookahead works with greedy and non-greedy matching in ANTLR3 and ANTLR4?

阅读更多关于 How Lexer lookahead works with greedy and non-greedy matching in ANTLR3 and ANTLR4?

问题 If someone would clear my mind from the confusion behind look-ahead relation to tokenizing involving greery/non-greedy matching i'd be more than glad. Be ware this is a slightly long post because it's following my thought process behind. I'm trying to write antlr3 grammar that allows me to match input such as: "identifierkeyword" I came up with a grammar like so in Antlr 3.4: KEYWORD: 'keyword' ; IDENTIFIER : (options {greedy=false;}: (LOWCHAR|HIGHCHAR))+ ; /** lowercase letters */ fragment

Parse stacked comparison expression into logical Conjunction Tree with antlr3

阅读更多关于 Parse stacked comparison expression into logical Conjunction Tree with antlr3

问题 I have run into a problem, when i tried to parse a stacked arithmetic comparison expression: "1<2<3<4<5" into a logical Tree of Conjunctions: CONJUNCTION(COMPARISON(1,2,<) COMPARISON(2,3,<) COMPARISON(3,4,<) COMPARISON(4,5,<)) Is there a way in Antlr3 Tree Rewrite rules to iterate through matched tokens and create the result Tree from them in the target language (I'm using java)? So i could make COMPARISON nodes from element x, x-1 of matched 'addition' tokens. I know i can reference the last

simple criteria expression parser with antlr3

阅读更多关于 simple criteria expression parser with antlr3

I want to create a simple criteria expression parser with antlr3 Updated: separate AND OR expression rules to support AND/OR different hierarchy, but got another problems: if the expression is something like: a = 1 and b = 2 and c = 3 The tree should be as following according to current implement: = = (a = 1)(b = 2)(c = 3) But I want to generate it as follows: = = (a = 1)(b = 2) (c = 3) First "and" should be higher priority than another, because I want to parse all the expression as left exp and right exp. I think I need to re-write the rule in the "subcond" To make a = 1 and b = 2 and c = 3 -

Python+ANTLR4: No module named antlr4

阅读更多关于 Python+ANTLR4: No module named antlr4

I would like to use ANTLR4 with Python 2.7 and for this I did the following: I installed the package antlr4-4.6-1 on Arch Linux with sudo pacman -S antlr4 . I wrote a MyGrammar.g4 file and successfully generated Lexer and Parser Code with antlr4 -Dlanguage=Python2 MyGrammar.g4 Now executing for example the generated Lexer code with python2 MyGrammarLexer.py results in the error ImportError: No module named antlr4 . What could to be the problem? FYI: I have both Python2 and Python3 installed - I don't know if that might cause any trouble. You need to install antlr4 for python through pip : sudo

regresion: Antlr C target follow set generates reference to undeclared identifier

阅读更多关于 regresion: Antlr C target follow set generates reference to undeclared identifier

ANTLRWorks 1.5rc1 successfully generated the C target code for this grammar with no warnings or errors but the C target code would not compile. ANTLRWorks 1.5 generated the same bad C target code but the console listed many template errors. ANTLRWorks 1.4.3 generated valid C target code that compiles without error. error C2065: 'FOLLOW_set_in_sqlCOMP_OP2185' : undeclared identifier Rule sqlCOMP_OP is referenced from multiple boolean expression rules All of the rules that generated references to undefined identifiers were of the form: fule: (Tokena | Tokenb | Tokenc)? Tokend; or there were

ANTLR grammar for scheme R5RS

阅读更多关于 ANTLR grammar for scheme R5RS

I'm beginner in ANTLR and I'm learning it by an example. I use C as my target language. The example is a Scheme R5RS grammar file taken from this question , with a little modification(rename the grammar name and add some options with the grammar specification untouched). antlr generated the lexer and parser, and I compile it with a test main() in which I just do some initialization and simply call the parser. When runing the test program with a piece of scheme code, the parser detect some syntax error(which should not happen!) main function in test.c #include <stdio.h> #include "r5rsLexer.h"