August 24

Welcome to Compilers! (P423, P523, E313, E513)

Instructor: Jeremy

What’s a compiler?

Table of Contents of Essentials of Compilation

Assignments, Quizzes, Exams, Grading, Academic Integrity

Technology

• Canvas FA21: COMPILERS: 18429 Link to real course web page Grades

• Web page: https://iucompilercourse.github.io/IU-Fall-2021/

• Communication: Slack http://iu-compiler-course.slack.com/

• Autograder: https://autograder.sice.indiana.edu/web/course/28

Concrete Syntax, Abstract Syntax Trees (AST)

• Programs in concrete syntax (Racket/Python)

    42                           42
  
    (read)                       input_int()
  
    (- 10)                       -10
  
    (+ (- 10) 5)                 -10 + 5
  
    (+ (read) (- (read)))        input_int() + -input_int()
  

• Racket structures for AST

    (struct Int (value))
    (struct Prim (op arg*))
  

• Python classes for AST

  Python ast module

  ast module type declarations

    class Constant(expr):
        value: Any
  
    class BinOp(expr):
        left: expr
        op: operator
        right: expr
  
    class UnaryOp(expr):
        op: unaryop
        operand: expr
  

• Grammars

  • Concrete syntax

    Racket style:

      exp ::= int | "(read)" | "(-" exp ")" | "(+" exp exp ")"
      exp ::= int | (read) | (- <exp> ) | (+ <exp> <exp>)
      L_Int ::= exp
    

    Python style:

      exp ::= int | input_int() | - exp | exp + exp
      stmt ::= print(exp) | exp
      L_Int ::= stmt*
    

  • Abstract syntax

    Racket:

      exp ::= (Int int) | (Prim 'read '()) 
          | (Prim '- (list exp))
          | (Prim '+ (list exp exp))
      L_Int ::= (Program '() exp)
    

    Python:

      exp ::= Constant(int) | Call(Name('input_int'), [])
          | UnaryOp(USub(), exp)
          | BinOp(exp, Add(), exp)
      stmt ::= Expr(Call(Name('print'), [exp])) | Expr(exp)
      L_Int ::= Module(stmt*)