CIT 594 Errata #2 for Bugs Grammar (and Code)
Spring 2008, David Matuszek

I never defined <direction>. It should just be <expression>.
Was: 
<turn action> ::= "turn" <direction> <eol>

<turnto action> ::= "turnto" <direction> <eol>
Now: 
<turn action> ::= "turn" <expression> <eol>

<turnto action> ::= "turnto" <expression> <eol>
Line breaks are significant in this language, and I left one out of the definition of <switch statement>. In addition, I've defined commands to include both statements and actions, and I did not mean to exclude the latter.
Was: 
<switch statement> ::= "switch" "{" <eol>
                         { "case" <expression>
                              { <statement> } }
                       "}" <eol>
Now: 
<switch statement> ::= "switch" "{" <eol>
                         { "case" <expression> <eol>
                              { <command> } }
                       "}" <eol>

I left the keywords var and initially out of the list of keywords in Token.java. Please add them in. In a related matter, I forgot to provide a definition for <initialization block>.

Now: 
<initialization block> ::= "initially" <block>

I left off the <eol> at the end of <bug definition>.

Was: 
<bug definition> ::= "Bug" <name> "{" <eol>
                         { <var declaration> }
                         [ <initialization block> ]
                         <command>
                         { <command> }
                         { <function definition> }
                    "}"
Now: 
<bug definition> ::= "Bug" <name> "{" <eol>
                         { <var declaration> }
                         [ <initialization block> ]
                         <command>
                         { <command> }
                         { <function definition> }
                    "}" <eol>
I have finished writing and debugging the Recognizer for the Bugs language, correcting the grammar as I go, so there should not be many additional changes for a while. When we begin work on the next parts (the Parser and the Interpreter), a couple more corrections will probably be needed.