antlr4

I'm trying to parse a Nested Boolean Expression and get the individual conditions within the expression separately. For e.g., if the input string is: (A = a OR B = b OR C = c AND ((D = d AND E = e) OR (F = f AND G = g))) I would like to get the conditions with the correct order. i.e., D =d AND E = e OR F = f AND G = g AND A = a OR B = b OR C = c I'm using ANTLR 4 to parse the input text and here's my grammar: grammar SimpleBoolean; rule_set : nestedCondition* EOF; AND : 'AND' ; OR : 'OR' ; NOT : 'NOT'; TRUE : 'TRUE' ; FALSE : 'FALSE' ; GT : '>' ; GE : '>=' ; LT : '<' ; LE : '<=' ; EQ : '=' ;

I need help with my ANTLR 4 grammar after deciding to switch to v4 from v3. I am not very experienced with ANTLR so I am really sorry if my question is dumb ;) In v3 I used the following code to detect Java-style comments: COMMENT : '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;} | '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;} ; In v4 there are no rule-specific options. The actions (move to hidden channel) are also invalid. Could somebody please give me a hint how to do it in ANTLR v4? The v4 equivalent would look like: COMMENT : ( '//' ~[\r\n]* '\r'? '\n' | '/*' .*? '*/' ) ->

I'm very new to ANTLR4 and am trying to build my own language. So my grammar starts at program: <EOF> | statement | functionDef | statement program | functionDef program; and my statement is statement: selectionStatement | compoundStatement | ...; and selectionStatement : If LeftParen expression RightParen compoundStatement (Else compoundStatement)? | Switch LeftParen expression RightParen compoundStatement ; compoundStatement : LeftBrace statement* RightBrace; Now the problem is, that when I test a piece of code against selectionStatement or statement it passes the test, but when I test it

I am parsing a C++ like declaration with this scaled down grammar (many details removed to make it a fully working example). It fails to work mysteriously (at least to me). Is it related to the use of context dependent predicate? If yes, what is the proper way to implement the "counting the number of child nodes logic"? grammar CPPProcessor; cppCompilationUnit : decl_specifier_seq? init_declarator* ';' EOF; init_declarator: declarator initializer?; declarator: identifier; initializer: '=0'; decl_specifier_seq locals [int cnt=0] @init { $cnt=0; } : decl_specifier+ ; decl_specifier : @init {

I want to parse few date format using following ANTLR4 grammar. grammar Variables; //varTable : tableNameFormat dateFormat? ; //tableNameFormat: (ID SEPERATOR); dateFormat : YEAR UNDERSCORE MONTH UNDERSCORE TODAY | YEAR ; YEAR : DIGIT DIGIT DIGIT DIGIT; // 4-digits YYYY MONTH : DIGIT DIGIT; // 2-digits MM TODAY : DIGIT DIGIT ; // 2-digits DD UNDERSCORE: ('_' | '-' ); fragment DIGIT : [0-9] ; ID : [a-zA-Z][a-zA-Z0-9]? ; WS : [ \t\r\n]+ -> skip ; This grammar should parse "2016-01-01" easily but it's giving input mismatch. Please help For such a task regex is much better solution. But if you

I have read many questions here on StackOverflow about mutual left-recursion issues in LL(k) parsers. I found the general algorithm for removing left-recursion: A : Aa | b ; becomes A : bR ; R : (aA)? ; However, I cannot figure out how to apply it to my situation. I have left_exp: IDENT | exp DOT IDENT ; exp : handful | of | other rules | left_exp ; The "handful of other rules" all contain regular recursion, such as exp : exp PLUS exp , etc. and have no issues. The issue is with left_exp and exp being mutually recursive. I thought about just adding IDENT and exp DOT IDENT to the exp rules, but

I created my grammar using antlr4 but I want to test robustess is there an automatic tool or a good way to do that fast Thanks :) The only way I found to create unit tests for a grammar is to create a number of examples from a written spec of the given language. This is neither fast, nor complete, but I see no other way. You could be tempted to create test cases directly from the grammar (writing a tool for that isn't that hard). But think a moment about this. What would you test then? Your unit tests would always succeed, unless you use generated test cases from an earlier version of the

I'm pretty new to ANTLR4 and now I'm trying to undertand which kind of grammars we might define with it. As far as I got, there're two kind of rules in ANTLR: parser rules (lower case words) and lexer rules (upper-case words). Example: grammar Test; init: prog(','prog)*; prog: A | prog ; A: [a-z]+; Form the grammar production rule standpoint I would say that parser rules are NON-TERMINAL symbols which can be replaced with a sequence of tokens defined by a lexer rules. So, it's perfectly clear that the grammar is context-free by the definition . The alpahbet of the language generated by the