with
使用 with 标签创建一个新的内部作用域。在此作用域内设置的变量在作用域外不可见
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{% with %}
{% set value = 42 %}
{{ value }} {# value is 42 here #}
{% endwith %}
value is not visible here any longer您无需在作用域的开头定义变量，而是可以传递您想要在 with 标签中定义的变量映射；之前的示例等同于以下示例
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{% with {value: 42} %}
{{ value }} {# value is 42 here #}
{% endwith %}
value is not visible here any longer
{# it works with any expression that resolves to a mapping #}
{% set vars = {value: 42} %}
{% with vars %}
...
{% endwith %}默认情况下，内部作用域可以访问外部作用域上下文；您可以通过附加 only 关键字来禁用此行为
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{% set zero = 0 %}
{% with {value: 42} only %}
{# only value is defined #}
{# zero is not defined #}
{% endwith %}