UP Lecture 09

Compilers
Grammar III
(202402)

Transcript

1. jgs Compilers Lecture 09: Grammars III Dr. Javier Gonzalez-Sanchez jgonzalezs@up.edu.mx
2. jgs Previously …
3. Dr. Javier Gonzalez-Sanchez | Compilers | 3 jgs Layering Rule 1 Rule 2 Rule 3 Rule 4 Rule 5 . . . . . Leaf (Terminals, i.e., Tokens) Root Start symbol Layers
4. Dr. Javier Gonzalez-Sanchez | Compilers | 4 jgs Layering 1 2 4 5 3 inputs: § 1 + 2 + 3 < 4 * 5 § 1 * 2 + 3 + 4 < 5 § 1 < 2 + 3 + 4 * 5 § 1 + 2 < 3 * 4 + 5 § 1 + 2 * 3 < 4 + 5
5. Dr. Javier Gonzalez-Sanchez | Compilers | 5 jgs Syntax Diagrams E A B C
6. Dr. Javier Gonzalez-Sanchez | Compilers | 6 jgs Exercise 1 Include rules for handling parenthesis into the previous grammar. The grammar should accept as correct the following expressions: 10 * 20 + 15 (10 * 20) + 15 10 * (20 + 15) (10) * (20) + (15) (10 * 20 + 15) 10 * (20) + 15
7. Dr. Javier Gonzalez-Sanchez | Compilers | 7 jgs Syntax Diagrams E A B C
8. jgs Test Yourselves
9. Dr. Javier Gonzalez-Sanchez | Compilers | 9 jgs Question {"name":false}
10. Dr. Javier Gonzalez-Sanchez | Compilers | 10 jgs Question {"name":false, "age" :100 }
11. Dr. Javier Gonzalez-Sanchez | Compilers | 11 jgs Question {"name":false, "age" :100, "grades”:[1,2,3] }
12. Dr. Javier Gonzalez-Sanchez | Compilers | 12 jgs Question {"name":false, "age" :100, "grades":{ "labs":[1,2,3] } }
13. jgs Next
14. Dr. Javier Gonzalez-Sanchez | Compilers | 14 jgs Exercise 2 Include rules to accept variables names (identifiers) in expressions. The grammar should accept as correct the following expressions: A * 20 + time (x * y) + 15 10 * (ASU + cse340) (10) * (20) + (15) (hello * world + Arizona) 10 * (counter) + 15
15. Dr. Javier Gonzalez-Sanchez | Compilers | 15 jgs Syntax Diagrams E A B C
16. Dr. Javier Gonzalez-Sanchez | Compilers | 16 jgs Exercise 3 Provide a Grammar that is Not ambiguous with Precedence of operators and Associativity for this: 10 + 20 > 15 & -10 != 1 | 20 / ( 10 + 1) < 5
17. Dr. Javier Gonzalez-Sanchez | Compilers | 17 jgs Exercise 3 | Note Precedence of operators | & ! < > == != <= >= + - * / - ( )
18. Dr. Javier Gonzalez-Sanchez | Compilers | 18 jgs Exercise 3 R EXPRESSION X Y
19. Dr. Javier Gonzalez-Sanchez | Compilers | 19 jgs Exercise 3 E A B C
20. jgs Test Yourselves
21. Dr. Javier Gonzalez-Sanchez | Compilers | 21 jgs Parser | Input and Output { 0; 1 + 2; 3 * (4 + hello); }
22. Dr. Javier Gonzalez-Sanchez | Compilers | 22 jgs Let’s Work
23. Dr. Javier Gonzalez-Sanchez | Compilers | 23 jgs Questions
24. Dr. Javier Gonzalez-Sanchez | Compilers | 24 jgs Homework Review Recursion
25. jgs Compilers Javier Gonzalez-Sanchez, Ph.D. jgonzalezs@up.edu.mx Spring 2024 Copyright. These slides can only be used as study material for the Compilers course at Universidad Panamericana. They cannot be distributed or used for another purpose.