TypoScript Syntax

1.3. Sorting out details

1.3.1. More about syntax, semantics and TypoScript compared to XML and XSLT

If you think you perfectly understand TypoScript now (you might already...) then don't bother with this section. I even risk confusing you again. But anyways, here it is - more theoretical information on TypoScript including references to the relationship between XML and XSLT:

XML and TypoScript - all about syntax:

A chunk of "TypoScript code" is like an XML document - it only contains information in a structured way, nothing else.  But in order to store information in TypoScript or XML you need to follow the syntax - rules about how the information values can be  inserted in the structure. Like the grammar for a human language defines in which order words can be combined.

For XML such rules include that "all tags must be ended, eg. <b>...</b> or <br />", correct nesting, using lowercase for element and attribute names etc. If you follow these rules an XML document is called "well formed". For TypoScript similar rules exist like "The = operator assigns the rest of the text string as the value to the preceeding object path" or "A line starting with # or / is a comment and therefore ignored".

XSLT and "TypoScript Templates" - all about semantics (meaning, function):

This is syntactically valid XML:

      <asdf>qwerty</asdf>

 

And this is syntactically valid TypoScript:

      asdf = qwerty

 

And this is syntactically valid English:

      footballs sing red

 

But none of these examples make sense without some reference which defines how elements, values and words can be combined in order to form meaning - they need a context. This is called semantics. For human languages we have it internally because we know footballs can't sing and you can't "sing red" - we know it's nonsense while the sentence is correctly formed. For an XML document you have it by the DTD or schema which defines if the element "<asdf>" exists on that level in the document (and if not, then it's nonsense) and for TypoScript you have it by the reference document for the context where the TypoScript syntax is used to define an information hierarchy - for instance the "TSref" for TypoScript Templates or the "TSconfig" document for "Page TSconfig" or "User TSconfig".

So an XML document makes sense only if you know the relationship of the information stored inside of the document and that is required if you want an XSLT stylesheet to transform one XML document to another document. In fact an XSLT stylesheet is like babelfish for XML - it translate one "language" of XML into another "language" of XML.

Similarly TypoScript is used as the syntax to build "TypoScript Templates" (containing semantics - meaning); the information only makes sense if it follows the rules defined in the "TSref" document.

BTW, the comparison of "TypoScript Templates" and "XSLT" is intensional since both can be described as declarational programming languages  - programming by configuring values which instructs a real procedural program  (eg. the TypoScript Frontend Engine which is written in PHP) how to output data. More is written on this issue on typo3.org.

For more on syntax and semantics, you can read this link that I found on the net.