handmade-compiler

Implement the lexical analyzer and syntax analyzer for a simplified Java programming language. Finally, implement the compiler.

Usage

lex_and_parse.py test2.java

Simplified java

< Lexical specifications >

• Variable type
  • int for a signed integer
  • char for a single character
  • boolean for a Boolean string
  • String for a literal string
• Signed integer
  • A single zero digit (e.g., 0)
  • A non-empty sequence of digits, starting from a non-zero digit
  • (e.g., 1, 22, 123, 56, … any non-zero positive integers)
  • (e.g., 001 is not allowed)
  • A non-empty sequence of digits, starting from a minus sign symbol and a non-zero digit
  • (e.g., -1, -22, -123, -56, .. any non-zero negative integers)
• Single character
  • A single digit, English letter, block, or any symbol, starting from and terminating with a symbol ‘ (e.g., ‘a’, ‘1’, ‘ ‘, ‘&’)
• Boolean string
  • true and false
• Literal string
  • Any combination of digits, English letters, and blanks, starting from and terminating with a symbol “ (e.g., “Hello world”, “My student id is 12345678”)
• An identifier of variables and functions
  • A non-empty sequence of English letters, digits, and underscore symbols, starting from an English letter or a underscore symbol
  • (e.g., i, j, k, abc, ab_123, func1, func_, func_bar)
• Keywords for special statements
  • if for if statement
  • else for else statement
  • while for while statement
  • class for class statement
  • return for return statement
• Arithmetic operators
  • +, -, *, and /
• Assignment operator
  • =
• Comparison operators
  • <, >, ==, !=, <=, and >=
• A terminating symbol of statements
  • ;
• A pair of symbols for defining area/scope of variables and functions
  • { and }
• A pair of symbols for indicating a function/statement
  • ( and )
• A pair of symbols for using an array
  • [ and ]
• A symbol for separating input arguments in functions
  • ,
• Whitespaces
  • a non-empty sequence of \t, \n, and blank

< CFG G >

1. S -> CODE
2. CODE -> CDECL CODE
3. CODE -> FDECL CODE
4. CODE -> VDECL CODE
5. CODE -> ''
6. VDECL -> vtype id semi
7. VDECL -> vtype ASSIGN semi
8. ASSIGN -> id assign RHS
9. RHS -> EXPR
10. RHS -> literal
11. RHS -> character
12. RHS -> boolstr
13. EXPR -> T addsub EXPR
14. EXPR -> T
15. T -> F multdiv T
16. T -> F
17. F -> lparen EXPR rparen
18. F -> id
19. F -> num
20. FDECL -> vtype id lparen ARG rparen lbrace BLOCK RETURN rbrace
21. ARG -> vtype id MOREARGS
22. ARG -> ''
23. MOREARGS -> comma vtype id MOREARGS
24. MOREARGS -> ''
25. BLOCK -> STMT BLOCK
26. BLOCK -> ''
27. STMT -> VDECL
28. STMT -> ASSIGN semi
29. STMT -> if lparen COND rparen lbrace BLOCK rbrace ELSE
30. STMT -> while lparen COND rparen lbrace BLOCK rbrace
31. COND -> COND comp C
32. C -> COND
33. C -> boolstr
34. ELSE -> else lbrace BLOCK rbrace
35. ELSE -> ''
36. RETURN -> return RHS semi
37. CDECL -> class id lbrace ODECL rbrace
38. ODECL -> VDECL ODECL
39. ODECL -> FDECL ODECL
40. ODECL -> ''