(Compiler theory) Lecture programming language and its grammar

basic concepts

1. Alphabet

• Alphabet operations: multiplication, n-th power, n closure, the Kleene closure (any symbol string set)
  

0 power is an empty string

• String operations: connecting, exponentiation
  

Defined grammar

1. Grammar formal definition:
   
2. Terminator: the basic language of symbolic token

• Not enclosed in angle brackets portion
  

3. Nonterminal symbol: indicates the syntax component symbols

• With angle brackets portion
  
  

5. S start symbol: the grammar largest grammatical elements.
   

Definition Language

1. Sentence: meet the rules of grammar end symbol string . A sentence that does not contain nonterminals sentence.
   
   

How to determine whether a word string satisfying the relation of the sentence? Deduction and reduction

2. Language
   
3. Derivation
4. Reduction
5. Operation on language

• and
• connection
• power
• Closure is
• Brooklyn closure

Classification grammar

1. Type 0 grammar: unrestricted grammar / phrase structure grammar
   
2. Type 1 grammar: context-sensitive grammar (CSG)

• Production does not contain null
  

3. Type 2 grammar: context-free grammar (CFG)
   
4. Type 3 Grammar: Regular Grammar
   
5. Relationship four kinds of grammar: the gradual restrictions, contains step by step
   

CFG parse tree

1. Sentence phrases: analysis of each of them in sub-edge tree tree
2. Direct phrases: height edge sub-tree 2
   

• Direct production phrase must be a right portion, a right portion of the production but not necessarily directly given sentence phrases

3. Ambiguous grammar: If a grammar can be generated for more than a sentence parse tree