Examples with ExprParser org.apache.druid.math.expr.antlr.ExprParser used on opensource projects

Example 1 with ExprParser

use of org.apache.druid.math.expr.antlr.ExprParser in project druid by druid-io.

the class Parser method parse.

@VisibleForTesting
public static Expr parse(String in, ExprMacroTable macroTable, boolean withFlatten) {
    ExprLexer lexer = new ExprLexer(new ANTLRInputStream(in));
    CommonTokenStream tokens = new CommonTokenStream(lexer);
    ExprParser parser = new ExprParser(tokens);
    parser.setBuildParseTree(true);
    ParseTree parseTree = parser.expr();
    ParseTreeWalker walker = new ParseTreeWalker();
    ExprListenerImpl listener = new ExprListenerImpl(parseTree, macroTable);
    walker.walk(listener, parseTree);
    Expr parsed = listener.getAST();
    if (parsed == null) {
        throw new RE("Failed to parse expression: %s", in);
    }
    return withFlatten ? flatten(parsed) : parsed;
}