look_ahead.py File Reference

Example of using the look behind operators & and !. More...

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Namespaces
	examples.basics.look_ahead

Variables
string	examples.basics.look_ahead.title
string	examples.basics.look_ahead.abnf_syntax = 'S = &(A !bb) 1*aa B !cc\n'
	examples.basics.look_ahead.api = Api()
	examples.basics.look_ahead.grammar = api.generate(abnf_syntax)
	examples.basics.look_ahead.parser = Parser(grammar)
string	examples.basics.look_ahead.input_string = 'aaabbbccc'
	examples.basics.look_ahead.result = parser.parse(utils.string_to_tuple(input_string))

Detailed Description

Example of using the look behind operators & and !.

A well-known non-context free language is L ={aⁿbⁿcⁿ | n>0}. It is shown there how to parse this using look ahead operators. See also the brute-force method with UDTs, namely hand written a code snippets to match a language phrase, examples/basics/udts.py.

Definition in file look_ahead.py.