User interface > Debugging and executing > Change of the start rule
What exactly happens, if you change a start rule depends of the things done before. During a TextTransformer session several situations can occur.
1. Change of the page: On the production page at last a different production was parsed (compiled) than is selected in the box of the tool bar. If you now go to the main page and start a transformation, the following box will appear:
2. Change of the start rule by the box of the tool bar: If the productions were compiled by Parse all scripts, a change is possible immediately.
However, if Parse connected scripts compiled them, the box above will appear, to confirm the change.
As well under point 1 as under point two there are two possibilities (if the scripts were parsed by Parse connected scripts):
a) The new rule already is compiled: If the new production is contained in the set of productions, of which the first start rule depends, the new rule will be parsed already too. But to execute it immediately is possible only, if the Interface option is enabled for this rule. If not, this rule first has to be compiled (automatically), to create a special scanner, which can test, whether the actual text is matched by one of the token of the rules first set.
b) The new rule is not compiled already: If the new production is not contained in the set of productions, of which the first start rule depends, it must be compiled.