CoDuck

TODO

• code generation using stack machines
• enums
• switch cases (should be easy)
• if variable is not initialized, then warning
• if variable is used without being initialized, then error (in char and strings only)
• if variable is not used, then warning
• Check if always false, then warning
• do until (easy)
• handling constant variables checks
• (Not sure if needed) treating INT as a subtype of REAL (double, floats) "y3ni momken a3mel assignment l variable float b int" in operations only
• check the symbol table format (scopes)
• print the scope symbol table as a table in the output file
• test the semantic analyzer more
• edit the error messages to be more indicative (super easy)

Table of Contents

• CoDuck
• TODO
• Table of Contents
• program structure
• Some limitations:
• Symbol table
• Language specs
  • Tokens
    • types keywords
    • conditional statement keywords
    • loops keywords
    • funciton keywords
    • enums
    • operators
    • symbols
    • Other tokens
    • Comments
    • Grammar design
      • Declarations
        • Variables
        • Constants
      • Expressions
      • Assignments
      • If-statement
      • Swicth...case
      • while-loops
      • Do Until loops
      • for-statements
      • Functions
      • enums
• How To Run
• Resources
  • Links
    • C Operator Precedence
    • C Grammar

program structure

1. // optional function declarations
2. // statements
3. // end;

Some limitations:

1. in for loops declaration (i=0; i<1; i++) is valid, but (int i=0; i<1; i++) is not
2. In case of initialization in the same line of declaration, only constants are allowed. i.e. integer x = 5; is valid, but integer x = y; is not
3. There's no bit-wise logical operations

Symbol table

• Global scope table is printed after parsing
• for each new scope, we create a new symboltable and we print it while exiting the scope

1. Global Symbol Table structure

==================================================================================
                                   Scope Symbol Table
------------ -------------- ------------ --------------------------- ------- ----------
Name         Type            Value       Parent Declared in          Scope   Line Numbers
------------ -------------- ------------ --------------------------- ------- ----------
a            INT            0            2                           1        4
b            INT            8            2                           1        5      6
j            INT            2            2                           1        3      10     15     22     27
==================================================================================

1. Block Symbol Table structure

=====================================================================
                       Main Symbol Table
------------ -------------- ------------ ------- -------------------
Name         Type            Value        Scope  Line Numbers
------------ -------------- ------------ ------- -------------------
test         STRING         (null)         0     48
coduck       INT            1              0     34
func1        func ret INT   0              0     2
===================================================================

Language specs

Tokens

types keywords

1. CHAR
2. INTEGER
3. FLOAT
4. BOOL
5. VOID
6. STRING

conditional statement keywords

1. IF

2. ELIF

3. ELSE

4. CASE

5. SWITCH

6. DEFAULT

7. true (case sensitive)

8. false (case sensitive)

loops keywords

1. WHILE
2. FOR
3. DO
4. UNTIL
5. CONTINUE
6. BREAK

funciton keywords

1. FUNC
2. RETURN

enums

1. ENUM

operators

1. ADD_OP +
2. SUB_OP -
3. MUL_OP*
4. DIV_OP/
5. MOD_OP%
6. INC_OP++
7. DEC_OP--
8. OR_OP||, or
9. AND_OP&&, and
10. NOT_OP!, not
11. EQ_OP==
12. NE_OP!=
13. LT_OP<
14. GT_OP>
15. LE_OP<=
16. GE_OP>=
17. ASSIGN_OP=
18. BIT_OR_OP|
19. & -> for REF and bitwise-and
20. BIT_XOR_OP^
21. BIT_LSHIFT_OP<<
22. BIT_RSHIFT_OP>>
23. BIT_NOT_OP~

symbols

1. LEFT_PAREN(
2. RIGHT_PAREN)
3. LEFT_SQ_BRACKET[
4. RIGHT_SQ_BRACKET]
5. LEFT_CURLY_BRACKET{
6. RIGHT_CURLY_BRACKET}
7. COMMA,
8. DOT.
9. SEMICOLON;
10. QUESTION_MARK?

Other tokens

1. IDENT
2. CONST_INT
3. CONST_FLOAT
4. CONST_CHAR
5. STRING_LITERAL

Comments

• Single line: // this is a single line comment
• Multi-line: /_ This is a Multi-line Comment _/

Grammar design

Declarations

Variables

a. examples

String S = "hello, world !"; // this is a string

String S2 = 'hii !'; // this is also a string

String _S = 5; // invalid indentifier

float float_number2 = .6; // invalid float

float float_number3 = 0.; // valid float

float float_number4 = 00.6 // invalid float

float float_number5 = -0.006 // valid float

integer x = 000 // invalid integer

Constants

Expressions

Assignments

If-statement

if(expression logical_operator expression){ // the parenthesis are optional
}elif(expression logical_operator expression){// the parenthesis are optional
}else{
}

Swicth...case

switch (expression){ // the parenthesis are optional
    case constant1:
      // statements
      break;

    case constant2:
      // statements
      break;
    .
    .
    .
    default:
      // default statements
}

while-loops

while(condition){ // parenthesis are optional


}

Do Until loops

do{
...
}until(condition); // parenthesis are optional

for-statements

for(var; cond; postfix;){
// parenthesis are optional
}

Functions

func function_name(type name, ...) return_type{
return value;
}

enums

enum Level {
  LOW,
  MEDIUM,
  HIGH
};

enum a{
x = 0,
y= 1
};

Quadruples

Quadruple	Quadruple Description
push J	used for the variables declarations (i.e int J;)
Add	used for the addtion of the two previous operands (i.e J = 1 + 2 will be 1 , 2, ADD)
store J	used for the store of the previous value in the variable J (i.e J = 1 + 2 will be 1 , 2, ADD, store J)
if false goto #	if condition false goto the else part at line (#)

Quadruples

Quadruple	Quadruple Description
push J	used for the variables declarations (i.e int J;)
Add,Sub,Mul,<,>	used for the addtion of the two previous operands (i.e J = 1 + 2 will be 1 , 2, ADD)
store J	used for the store of the previous value in the variable J (i.e J = 1 + 2 will be 1 , 2, ADD, store J)
if false goto #	if condition false goto the else part at line (#)

How To Run

cd to the project directory "design/tests"

• Run the following command to compile the code

bison -d  parser.y
flex lex.l
gcc -o compiler parser.tab.c lex.yy.c
rm lex.yy.c parser.tab.c

• to run a test file, run the following command

.\compiler test_file_name symbol_table_file_name revisit_queue_file_name

example:

.\compiler full_example.kak  symbol_table_full_example.out revisit_queue_full_example.out

Resources

Links

C Operator Precedence

https://en.cppreference.com/w/c/language/operator_precedence

C Grammar

http://marvin.cs.uidaho.edu/Teaching/CS445/c-Grammar.pdf