Foundations of Software - LAMP - EPFL

The Basic Idea
For each language (identified by grammar symbol S), define a
function fS that, given an input stream i,
� if a prefix of i is in S, return Success(Pair(x, i ′ )) where x is
a result for S and i ′ is the rest of the input.
� otherwise, return Failure(msg, i) where msg is an error
message string.
The first behavior is called success, the second failure.
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