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https://github.com/silverstripe/silverstripe-framework
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97 lines
2.5 KiB
Markdown
97 lines
2.5 KiB
Markdown
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# Formal Treatment of the Template Language
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This document gives you the maximum level of detail of how the template engine works. If you just want to know how to write templates, you probably want to read [this page](/reference/templates) instead.
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## White space
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## Expressions
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### Literals
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Definition:
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literal := number | stringLiteral
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number := digit { digit }*
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stringLiteral := "\"" { character } * "\"" |
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"'" { character } * "'"
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Notes:
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* digits in a number comprise a single token, so cannot have spaces
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* any printable character can be included inside a string literal except the opening quote, unless
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prefixed by a backslash (TODO: check this assumption with Hamish - its probably not right)
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### Words
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A word is used to identify a name of something, e.g. a property or method name. Words must start
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with an alphabetic character or underscore, with subsequent characters being alphanumeric or underscore:
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word := A-Za-z_ { A-Za-z0-9_ }*
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### Properties and methods (variables)
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Examples:
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$PropertyName.Name
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$MethodName
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$MethodName("foo").SomeProperty
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$MethodName("foo", "bar")
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$MethodName("foo", $PropertyName)
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Definition:
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injection := "$" lookup | "{" "$" lookup "}"
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call := word [ "(" argument { "," argument } ")" ]
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lookup := call { "." call }*
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argument := literal |
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lookup |
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"$" lookup
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Notes:
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* A word encountered with no parameter can be parsed as either a property or a method. TODO:
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document the exact rules for resolution.
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* TODO: include Up and Top in here. Not syntactic elements, but worth mentioning their semantics.
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* TODO: consider the 2.4 syntax literals. These have been excluded as we don't want to encourage their
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use.
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### Operators
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<exp> == <exp>
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<exp> = <exp>
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<exp> != <exp>
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<exp> || <exp>
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<exp> && <exp>
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* TODO: document operator precedence, and include a descripton of what the operators do. || and && are short-circuit? Diff
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between = and == or are they equivalent.
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## Comments
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## If
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if := ifPart elseIfPart* elsePart endIfPart
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ifPart := "<%" "if" ifCondition "%>" template
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elseIfPart := "<%" "else_if" ifCondition "%>" template
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elsePart := "<%" "else" "%>" template
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endIfPart := "<%" "end_if" "%>"
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ifCondition := TODO
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template := TODO
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## Require
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## Loop
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## With
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## Translation
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## Cache block
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TODO to be elaborated
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<cached arguments>...<end_cached>
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<cacheblock arguments>...<end_cacheblock>
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<uncached>...<uncached>
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