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package org.ssssssss.script.parsing.ast.statement;

import org.ssssssss.script.asm.Label;
import org.ssssssss.script.compile.MagicScriptCompiler;
import org.ssssssss.script.parsing.Span;
import org.ssssssss.script.parsing.ast.Expression;
import org.ssssssss.script.parsing.ast.Node;
import org.ssssssss.script.runtime.handle.OperatorHandle;

import java.util.List;

public class WhileStatement extends Node {

	private final Expression condition;
	private final List trueBlock;

	public WhileStatement(Span span, Expression condition, List trueBlock) {
		super(span);
		this.condition = condition;
		this.trueBlock = trueBlock;
	}

	@Override
	public void visitMethod(MagicScriptCompiler compiler) {
		condition.visitMethod(compiler);
		trueBlock.forEach(it -> it.visitMethod(compiler));
	}

	@Override
	public void compile(MagicScriptCompiler compiler) {
		Label start = new Label();
		Label end = new Label();
		compiler.markLabel(start, end)    // 标记 continue 和 break 位置
				.label(start)
				// 判断是否为true
				.visit(condition)
				.invoke(INVOKESTATIC, OperatorHandle.class, "isTrue", boolean.class, Object.class)
				// 值为false时，跳出循环
				.jump(IFEQ, end)
				// 执行循环体
				.compile(trueBlock)
				// 执行完毕后跳转到循环起始位置
				.jump(GOTO, start)
				.label(end)
				.exitLabel();

	}
}