Class GroupChoice

Determine whether an output sequence created from the symbols can be made consistent with the model.

The symbol set represents letters in an alphabet; the output sequence orders those letters in a way that satisfies the regular expression expressed in the model. Both are changed as a result of a successful validation; both remain unchanged if the validation failed. In recursing, implementers may assume that output_sequence is monotonic: its length remains unchanged after an invocation iff the symbol set also remains unchanged. The _validateCloneSymbolSet, _validateCloneOutputSequence, and _validateReplaceResults methods are available to help preserve this behavior.

Parameters:

• symbol_set - A map from ElementUse instances to a list of values. The order of the values corresponds to the order in which they should appear. A key of None identifies values that are stored as wildcard elements. Values are removed from the lists as they are used; when the last value of a list is removed, its key is removed from the map. Thus an empty dictionary is the indicator that no more symbols are available.
• output_sequence - A mutable list to which should be appended tuples ( eu, val ) where eu is an ElementUse from the set of symbol keys, and val is a value from the corresponding list. A document generated by producing the elements in the given order is expected to validate.

Returns:

True iff the model validates. symbol_set and output_path will be unchanged if this returns False.

Overrides: ContentModel_mixin._validate

(inherited documentation)