Attention

TYPO3 v6 has reached its end-of-life April 18th, 2017 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.

There is no further ELTS support. It is strongly recommended updating your project.

Register

It is possible to store variable values into a memory stack which is called "register". The cObjects LOAD_REGISTER and RESTORE_REGISTER provide this storage functionality. Some TYPO3 cObjects use internal registers. Esp. the menus are built be registers (e.g. count_HMENU, count_HMENU_MENUOBJ, count_menuItems).

Defining registers

Registers in TypoScript can be seen as stack array variables in programming languages. Each register can store a complex TypoScript block. Use LOAD_REGISTER to put a variable to the stack, use RESTORE_REGISTER to pull a variable from the stack and curly braces around a variable name to read the current value of the variable. You need a stdWrap.data or a stdWrap.dataWrap cObject. The registers cannot be read on other places than inside of these cObjects.

Example

10 = COA
10 {
    ### left menu table column
    10 = LOAD_REGISTER
    10 {
        ulClass = col-left
    }

    ### right menu table column
    20 = LOAD_REGISTER
    20 {
        ulClass = col-right
    }

    30 = HMENU
    30 {
        special = list
        special.value = 1
        1 = TMENU
        # ...
        3 = TMENU
        3 {
            stdWrap {
                preCObject = COA
                preCObject {
                    10 = RESTORE_REGISTER
                }
                dataWrap = <ul class="{register:ulClass}">|</ul>
            }
            wrap =
            SPC = 1
            SPC {
                allStdWrap {
                    replacement {
                        10 {
                            search = ---
                            replace =
                        }
                    }
                    dataWrap = </ul>|<ul class="{register:ulClass}">
                }
            }
        }
    }
}

This example shows a part of a TypoScript which builds a 2 column menu based on a spacer page. A class is added to the ul tag depending on the value of the register variable ulClass. The first pages will have the class col-left and the pages following the spacer page will get the class col-right.

{register:variablename} returns the "current" value of the variable variablename. A register stack can be like any TypoScript setup.

10 = COA
10 {
  10 = LOAD_REGISTER
  10 {
      ulClass = col-left
      aClass = a-special
      colors {
          chief = red
          servant = white
      }
  }
}

The "current" value is just an internal variable that can be used by functions to pass a single value on to another function later in the TypoScript processing. It is like "load accumulator" in the good old C64 days. Basically you can use a "register" as you like. The TSref will tell if functions are setting this value before calling some other object so that you know if it holds any special information.