Tag Reference

The concept of a tag

In JNTemplate, a tag refers specifically to a syntax block that contains template code. It is the basic rendering unit: once template parsing is complete, that syntax block is replaced by concrete data or content.

Tag categories

By the way they are written, tags fall into two kinds: full tags and shorthand tags (tag prefixes and suffixes are configurable; this document uses the default configuration):

• Full tag: starts with ${ and ends with }, for example ${tagName}
• Shorthand tag: starts with $ and ends at a whitespace character, for example $tagName

Normally, the vast majority of tags can use the shorthand form, which looks cleaner. However, shorthand tags cannot be used in the following cases:

1. Arithmetic expressions and logical expressions must use full tags, e.g. ${3+5} cannot be shortened to $3 + 5.
2. When the tag is followed by a period, a letter or a digit, a full tag must be used. For example ${siteHost}.com cannot be shortened to $siteHost.com.
3. When whitespace or other characters that require a full tag appear after the tag.

By type, tags fall into basic tags and complex tags.

• Basic tag: all code is contained between the tag prefix ${ and the tag suffix }. Basic tags are further divided into ordinary basic tags, special tags and child tags.
  • Ordinary tag: a plain basic tag.
  • Special tag: generally has a special meaning, equivalent to a system keyword in a programming language.
  • Child tag: a tag that has a parent tag, where the parent is usually another basic tag.
• Complex tag: composed of one or more basic tags.

Tag relationships

.
└── Tag
    ├── Complex tag
    └── Basic tag
        ├── Ordinary tag
        ├── Special tag
        └── Child tag

TIP

All examples in this document use the default parameters; exceptions are called out explicitly.