The now function returns the current system time as a string value, in the canonical format defined within the XForms specification. If local time zone information is available, it is included in the string. The submit function immediately submits the instance data bound to the node that contains the expression. The reset function immediately resets the instance data bound to the node that contains the expression. When tokenizing, the longest possible token is always returned.
Names follow the lexical rules for XML NAME tokens.
Function names, however, are not permitted to include - or . for compatibility with externally defined functions. Parentheses can be used for grouping, but otherwise have no effect on the semantics of Dynamic Constraints. The syntax caters for literals for null, booleans, numbers, and strings. This section will be expanded in future revisions, to cover extension functions and methods for calling out to script.