Text Expression

Text expressions are used in the explanation field, question field and in text rules of a parameter declaration. In sections text expressions are used as advice.

Text expressions can be a mixture of strings and the values of some parameters and text functions. Using the name of a parameter causes the value of that parameter to be displayed as part of the compound text. The & character can be used to insert new lines in the text. The syntax for a text expression is:

<text-expression> ::= <simple-text> { <text-expression> }

<simple-text> ::= <string> | <parameter-name> | & |

<text-function>( <argumentlist> )

<text-function> ::= concat | startstr | endstr

<argumentlist> ::= <argument> {, <argumentlist> }

<argument> ::= <text-expression>

The text functions are:

concat(X,Y) returns the string X concatenated with Y

startstr(N,X) returns the first N characters from the string X

endstr(N,X) returns the last N characters from the string X

Examples

'this text' & 'will be displayed on' & 'three seperate lines'

The following example uses three strings and the value of two parameters - animal and favourite_food:

'The favourite food of the ' animal ' is ' favourite_food '.'

The resulting display on the screen might be:

The favourite food of the koala is eucalyptus leaves.

The following test will only accept those days of the week starting with a 't', i.e. tuesday or thursday:

startstr(1,name_of_day) = 't'