lexical analyzersymbol table - holds the symbols

Question

Lexical Analyzer:

Symbol Table - Holds the symbols accepted by the lexical analyzer or parser. 

Each symbol may be a terminal or a non-terminal.  Terminal symbols are listed first in the table ahead of non-terminals.

Attributes:

• Count - Number of symbols in the table

Child items:

• Symbol

Symbol - Individual symbol accepted by the lexical analyzer or parser. 

Attributes:

• Index - Unique symbol identifier in the symbol table
• Name - Name assigned to symbol in the grammar
• Kind - Indicates the type of symbols. (0- nonterminal, 1 - terminal, other types are self evident)

Char Sets - Groups of characters that can trigger one (or more) DFA state transitions. 

Attributes:

• Index - Unique identifier for a given character set
• Count - Number of characters in a given character set

Child items:

• Char

Char - Specifies the individual character (no array needed)

Attributes:

• Unicode Index - Character code in Unicode (ASCII)

 

DFA Table - Holds all the DFA states that make up the lexical analyzer. 

Attributes:

1.       Count - Number of DFA states

2.       Initial state

Child Items:

1.       DFA State

DFA State - Enumerates each DFA state and the edges that transition from that state.

Attributes:

• Index - Unique identifier (order in the DFA table)
• EdgeCount - Number of edges from the current state to other DFA states
• AcceptSymbol - Is this an accept state?
• -1=false
• Otherwise, it gives the number of the symbol index the state accepts

Child items:

• DFA Edge

DFA Edge - Transition from one DFA state to another

Attributes:

• Char Set Index - Points to the character set whose input causes the transition. Thus, a single transition may be cause by multiple characters.
• Target - Points to the destination state for the transition