COMPILER PROJECT 2024
The goal of the term-project is to implement a bottom-up syntax analyzer (a.k.a., parser) as we’ve
learned. More specifically, you will implement the syntax analyzer for a simplified C programming
language with the following context free grammar G;
CFG G:
01: CODE → VDECL CODE | FDECL CODE | ϵ
02: VDECL → vtype id semi | vtype ASSIGN semi
03: ASSIGN → id assign RHS
04: RHS → EXPR | literal | character | boolstr
05: EXPR → EXPR addsub EXPR | EXPR multdiv EXPR
06: EXPR → lparen EXPR rparen | id | num
07: FDECL → vtype id lparen ARG rparen lbrace BLOCK RETURN rbrace
08: ARG → vtype id MOREARGS | ϵ
09: MOREARGS → comma vtype id MOREARGS | ϵ
10: BLOCK → STMT BLOCK | ϵ
11: STMT → VDECL | ASSIGN semi
12: STMT → if lparen COND rparen lbrace BLOCK rbrace ELSE
13: STMT → while lparen COND rparen lbrace BLOCK rbrace
14: COND → COND comp COND | boolstr
15: ELSE → else lbrace BLOCK rbrace | ϵ
16: RETURN → return RHS semi
✓ Terminals (21)
1. vtype for the types of variables and functions
2. num for signed integers
3. character for a single character
4. boolstr for Boolean strings
5. literal for literal strings
6. id for the identifiers of variables and functions
7. if, else, while, and return for if, else, while, and return statements respectively 8. class for class declarations
9. addsub for + and - arithmetic operators
10. multdiv for * and / arithmetic operators
11. assign for assignment operators
12. comp for comparison operators
13. semi and comma for semicolons and commas respectively
14. lparen, rparen, lbrace, and rbrace for (, ), {, and } respectively
✓ Non-terminals (13)
CODE, VDECL, ASSIGN, RHS, EXPR, FDECL, ARG, MOREARGS, BLOCK, STMT, COND, ELSE,
RETURN
✓ Start symbol: CODE
Descriptions
✓ The given CFG G is non-left recursive, but ambiguous.
✓ Codes include zero or more declarations of functions and variables (CFG line 1)
✓ Variables are declared with or without initialization (CFG line 2 ~ 3)
✓ The right hand side of assignment operations can be classified into four types; 1) arithmetic
operations (expressions), 2) literal strings, 3) a single character, and 4) Boolean strings (CFG
4)
✓ Arithmetic operations are the combinations of +, -, *, / operators (CFG line 5 ~ 6)
✓ Functions can have zero or more input arguments (CFG line 7 ~ 9)
✓ Function blocks include zero or more statements (CFG line 10)
✓ There are four types of statements: 1) variable declarations, 2) assignment operations, 3) ifelse
statements, and 4) while statements (CFG line 11 ~ 13)
✓ if and while statements include a conditional operation which consists of Boolean strings
and condition operators (CFG line 12 ~ 14) ✓ if statements can be used with or without an else statement (CFG line 12 & 15)
✓ return statements return 1) the computation result of arithmetic operations, 2) literal strings,
3) a single character, or 4) Boolean strings (CFG line 16)
✓ This is not a CFG for C. This is for simplified C. So, you don’t need to consider grammars
and structures not mentioned in this specification.
Based on this CFG, you should implement a bottom-up parser as follows:
✓ Discard an ambiguity in the CFG
✓ Construct a SLR parsing table for the non-ambiguous CFG through the following website:
http://jsmachines.sourceforge.net/machines/slr.html
✓ Implement a SLR parsing program for the simplified Java programming language by using the
constructed table.
For the implementation, please use C, C++, or Python (If you want to use . Your syntax analyzer
must run on Linux or Unix-like OS without any error.
Your syntax analyzer should work as follows:
✓ The execution flow of your syntax analyzer:
syntax_analyzer <input file>
✓ Input: A sequence of tokens (terminals) written in the input file
e.g., vtype id semi vtype id lparen rparen lbrace if lparen boolstr comp boolstr rparen lbrace
rbrace
✓ Output
◼ (If a parsing decision output is “accept”) please construct a parse tree (not abstract
syntax tree) for the input sequence
◆ You can design the data structure to represent the tree as you want.
◼ (If an output is “reject”) please make an error report which explains why and where the error occurred (e.g., line number)
Term-project schedule and submission
✓ Deadline: 6/9, 23:59 (through an e-class system)
◼ For a delayed submission, you will lose 0.1 * your original project score per each
delayed day
✓ Submission file: team_<your_team_number>.zip or .tar.gz
◼ The compressed file should contain
◆ The source code of your syntax analyzer with detailed comments
◆ The executable binary file of your syntax analyzer (if you implemented using
a complied language)
◆ Documentation (the most important thing!)
⚫ It must include 1) your non-ambiguous CFG G and 2) your SLR parsing table
⚫ It must also include any change in the CFG G and all about how your syntax
analyzer works for validating token sequences (for example, overall
procedures, implementation details like algorithms and data structures,
working examples, and so on)
◆ Test input files and outputs which you used in this project
⚫ The test input files are not given. You should make the test files, by yourself,
which can examine all the syntax grammars.
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