antlr
The syntax parsing time and performance did not meet my expectations
Hello, I have customized the syntax using Antlr4 (4.13.2), but when using the parser to parse, I found that the general performance loss for each syntax parsing is about 50ms. Our project can only allow us to control it within about 5ms. I am not sure if it is because our syntax definition is inaccurate, and the performance supported by Antlr4 can only reach this limit. Can you help answer my question?（java） `grammar DataFusion;
@header{ package org.example.code; }
options { language = Java; }
// DataFusion 语法定义jql jql: elements end ;
elements: element (',' element)* ; // Simplified to allow for easier parsing of multiple elements
element: ID ':' (strings | constant | function | expr) // Simplified and removed unnecessary alternatives | all | ignore ;
expr: term (op=('+'|'-') term)* | factor (op=(''|'/') factor) | number | strings | function | '(' expr ')' ;
term: factor (op=('+'|'-') factor) *; factor: number | strings | function | '(' expr ')' | ID;
function: AGGOPER '(' argument ')' | IFNULL '(' number ',' strings ',' argument ')' | CONCAT '(' strings (',' strings)* ')' ;
argument: strings | number | expr | constant ;
number: INTEGER | FLOAT ;
strings : ID ;
end : ';';
constant: ''' ID ''' | '''''' | ''' (INTEGER | FLOAT) ''';
all : '' | ID '' ;
ignore : '-$'ID | '-$'all;
AGGOPER: 'SUM' | 'sum' | 'AVG' | 'avg' | 'COUNT' | 'count' | 'MAX' | 'max' | 'MIN' | 'min' ;
IFNULL: 'IFNULL' | 'ifnull' ;
CONCAT: 'CONCAT' | 'concat';
FLOAT : '-'? DIGIT+ '.' DIGIT+ ; fragment DIGIT : [0-9] ; ID : [a-zA-Z0-9_$\u0080-\uffff.]+ ; Grammar_EOF: ';' ; WS: [ \t\r\n]+ -> skip;` 解析耗时：57ms
The grammar you provide is not valid. It doesn't pass the Antlr Tool. Please use correct Markdown syntax for code blocks.
The grammar looks highly ambiguous and precedence looks incorrect. Use the recognizer options to report ambiguities s you parse then fix the grammar. Then you can use SLL mode and should teach your required parsing times easily. You have to work at a grammar and understand it to get good performance
On Mon, Aug 26, 2024 at 06:41 Ken Domino @.***> wrote:
The grammar you provide is not valid. It doesn't pass the Antlr Tool. Please use correct Markdown syntax for code blocks.
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