Simulation

Valid LL(1) Grammars

For any production S -> A | B, it must be the case that:

• For no terminal t could A and B derive strings beginning with t
• At most one of A and B can derive the empty string
• if B can derive the empty string, then A does not derive any string beginning with a terminal in Follow(A)

Formatting Instructions

• The non-terminal on the left-hand-side of the first rule is the start non-terminal
• Write each production rule in a separate line (see example to the left)
• Separate each token using whitespace
• $ is reserved as the end-of-input symbol, and S is reserved as an artificial start symbol. The grammar is automatically augmented with the rule S -> start $

Debugging

• More information about the parser construction is printed on the console
• The source code follows the pseudocode in lecture. In particular, see computeNullable, computeFirst, computeFollow, and computeLL1Tables