ReturnIfParser.java

/**
 * Copyright (C) 2013-2016 The Rythm Engine project
 * for LICENSE and other details see:
 * https://github.com/rythmengine/rythmengine
 */
package org.rythmengine.internal.parser.build_in;

import com.stevesoft.pat.Regex;
import org.rythmengine.internal.IContext;
import org.rythmengine.internal.IParser;
import org.rythmengine.internal.Keyword;
import org.rythmengine.internal.Token;
import org.rythmengine.internal.parser.ParserBase;
import org.rythmengine.utils.S;

/**
 * Parse @returnIf(expression) statement. Which break the current
 * template execution and return to caller if the expression
 * evaluated to {@code true}
 */
public class ReturnIfParser extends KeywordParserFactory {

    @Override
    public Keyword keyword() {
        return Keyword.RETURN_IF;
    }

    public IParser create(final IContext ctx) {
        return new ParserBase(ctx) {
            public Token go() {
                Regex r = reg(dialect());
                if (!r.search(remain())) {
                    raiseParseException("error parsing @returnIf, correct usage: @returnIf(<expression>)");
                }
                final String matched = r.stringMatched();
                if (matched.startsWith("\n") || matched.endsWith("\n")) {
                    //ctx.getCodeBuilder().addBuilder(new Token.StringToken("\n", ctx));
                    Regex r0 = new Regex("\\n([ \\t\\x0B\\f]*).*");
                    if (r0.search(matched)) {
                        String blank = r0.stringMatched(1);
                        if (blank.length() > 0) {
                            ctx.getCodeBuilder().addBuilder(new Token.StringToken(blank, ctx));
                        }
                    }
                } else {
                    Regex r0 = new Regex("([ \\t\\x0B\\f]*).*");
                    if (r0.search(matched)) {
                        String blank = r0.stringMatched(1);
                        if (blank.length() > 0) {
                            ctx.getCodeBuilder().addBuilder(new Token.StringToken(blank, ctx));
                        }
                    }
                }
                step(matched.length());
                String condition = r.stringMatched(2);
                if (null != condition) {
                    condition = S.stripBrace(condition);
                }
                if (S.empty(condition)) {
                    raiseParseException("expression required by @returnIf directive");
                }
                return new IfThenToken(condition, "return this", ctx());
            }
        };
    }

    @Override
    protected String patternStr() {
        return "^(\\n?[ \\t\\x0B\\f]*%s%s\\s*((?@()))[\\s;]*)";
    }

}