Removal of Lambda Productions
The removal of lambda productions involves two steps:
Each step must be done in order. Below is a picture of the lambda production removal window:
NOTE: In the grammar listboxes, lambda is represented as the character "Ø"
Step 1: Finding variables that derive lambda
The variables that derive lambda are the variables that have
lambda on the right side of their productions. Input these
variables into the input field separated by commas or spaces.
Then, press "Check" to verify that it is correct. If
you want to see the correct answer press "Show".
Step 2: Modifying the grammar to remove the lambdas
Modifying the grammar involves removing and adding new
productions. In the left pane, the grammar that is being modified
is shown. In the right pane, the initial grammar is provided
for refrence. Four operations can be performed when modifying a grammar:
Removing lambda productions involves removing the productions that derive lambda, then adding new productions that exclude the productions that produce lambda. For example, if a grammar contained the rules:
A->Ø
B->cAd
Then you would remove A->Ø and add B->cd.
Step 3: Continuing
To continue on to the next transformation press the "Next
Transformation" button. If you want to parse the grammar to
see the derivation of an acceptance string then press the
"Parse" button.