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https://github.com/silverstripe/silverstripe-framework
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43 lines
2.4 KiB
Markdown
43 lines
2.4 KiB
Markdown
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# Moving from SilverStripe 2 to SilverStripe 3
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These are the main changes to the SiverStripe 3 template language.
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## Control
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The `<% control var %>...<% end_control %>` in SilverStripe prior to version 3 has two different meanings. Firstly, if the control variable is a collection (e.g. DataObjectSet), then `<% control %>` iterates over that set. If it's a non-iteratable object, however, `<% control %>` introduces a new scope, which is used to render the inner template code. This dual-use is confusing to some people, and doesn't allow a collection of objects to be used as a scope.
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In SilverStripe 3, the first usage (iteration) is replaced by `<% loop var %>`. The second usage (scoping) is replaced by `<% with var %>`
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## Literals in Expressions
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Prior to SilverStripe 3, literal values can appear in certain parts of an expression. For example, in the expression `<% if mydinner=kipper %>`, `mydinner` is treated as a property or method on the page or controller, and `kipper` is treated as a literal. This is fairly limited in use.
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Literals can now be quoted, so that both literals and non-literals can be used in contexts where only literals were allowed before. This makes it possible to write the following:
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* `<% if $mydinner=="kipper" %>...` which compares to the literal "kipper"
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* `<% if $mydinner==$yourdinner %>...` which compares to another property or method on the page called `yourdinner`
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Certain forms that are currently used in SilverStripe 2.x are still supported in SilverStripe 3 for backwards compatibility:
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* `<% if mydinner==yourdinner %>...` is still interpreted as `mydinner` being a property or method, and `yourdinner` being a literal. It is strongly recommended to change to the new syntax in new implementations. The 2.x syntax is likely to be deprecated in the future.
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Similarly, in SilverStripe 2.x, method parameters are treated as literals: `MyMethod(foo)` is now equivalent to `$MyMethod("foo")`. `$MyMethod($foo)` passes a variable to the method, which is only supported in SilverStripe 3.
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## Method Parameters
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Methods can now take an arbitrary number of parameters:
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$MyMethod($foo,"active", $CurrentMember.FirstName)
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Parameter values can be arbitrary expressions, including a mix of literals, variables, and even other method calls.
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## Less sensitivity around spaces
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Within a tag, a single space is equivalent to multiple consequetive spaces. e.g.
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<% if $Foo %>
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is equivalent to
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<% if $Foo %>
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