Guide.md

Github: https://github.com/dhruvilmehta/Pascal-Compiler The whole compiler which you are running is made by me and the source code can be found at the above Github link or in the src/ directory. I have created this compiler in Java and you can view how parser and executors run. In this document I have tried to give a brief high-level overview of what I have built. I have also included my name in some of the inbuilt functions to show proof-of-work. Each and everything here is made from scratch using java. Details on how to run the code is found in Readme.md file.

Hello world into my compiler:(hello.pas for more details) PROGRAM hello (output); BEGIN {hello} writelndhruvil('Hello, world.'); END; END {hello}.

Example If-Else statement: (iftest.pas for more details) IF i = 1 THEN f := 10 ELSE IF i = 2 THEN f := 20 ELSE IF i = 3 THEN t := 30 ELSE IF i = 4 THEN f := 40 ELSE f := -1;

Example array program: Visit: arraytest.pas (in current directory)

A record in Pascal: (declarations.pas for more details) rec1 = RECORD i : integer; r : real; b1, b2 : boolean; c : char END;

For and nested for loops: (fortest.pas for more details) FOR k := j TO 5 DO n := k;

FOR k := n DOWNTO 1 DO j := k;

FOR i := 1 TO 2 DO 
    BEGIN
        FOR j := 1 TO 3 DO 
            BEGIN
                k := i*j
            END
    END

While loop: (whileloop.pas for more details) WHILE root*root - number > 0.000001 DO BEGIN root := (number/root + root)/2 END

Example Switch case: (casetest.pas for more details) CASE i+1 OF 1: j := i; -8: j := 8i; 5, 7, 4: j := 574i; END;

Example function and procedure: FUNCTION root(x : real) : real; VAR r : real;

    BEGIN
        r := 1;
        REPEAT
            r := (x/r + r)/2;
        UNTIL abs(x/sqr(r) - 1) < epsilon;
        root := r;
    END;

PROCEDURE print(n : integer; root : real);
    BEGIN
        writeln('The square root of ', number:4, ' is ', root:8:4);
    END;

Example read and write function: (readtest.pas for more details) write('Type an integer: '); readln(i); writeln('You typed: ', i); writeln;

Example Repeat statement in Pascal: (repeattest.pas for more details) REPEAT r := (n/r + r)/2 UNTIL r*r - n < epsilon;

Subrange type declaration: (range1.pas for more details) TYPE subrange = 10..20;

Nested Procedures: (routines.pas for more details) PROCEDURE nested(VAR n, m : integer); CONST ten = 10;

    TYPE
        subrange = five..ten;

    VAR
        a, b, c : integer;
        s : subrange;

    PROCEDURE deeply;

        VAR
            w : real;

        BEGIN
            w := i;
            nested(a, m);
            w := forwarded(b, w);
        END;

    BEGIN {nested}
        s := m;
        deeply;
        a := s;
    END {nested};

Assignment and decision making operations: (StringTest.pas for more details) PROCEDURE testStrings(VAR s5 : string5; s8 : string8);

    VAR
        b1, b2, b3 : boolean;

    BEGIN
        b1 := s5 > s8;
        b2 := s5 < 'goodbye';
        b3 := 'nobody' >= s8;

        writeln(b1:6, b2:6, b3:6);
    END;

Some inbuilt or Predefined Functions: Procedures 1. writedhruvil: Writes a string or expression to standard output. 2. writelndhruvil: Writes a string or expression to standard output with a new line at the end. 3. readdhruvil: Reads input from standard input (keyboard) and assigns it to a variable. 4. readlndhruvil: Reads a line of input from standard input (keyboard) and assigns it to a variable.

Functions
1. abs: Returns the absolute value of a number.
2. arctan: Returns the arctangent of a number.
3. chr: Converts an integer value to its corresponding character.
4. cos: Returns the cosine of a number (in radians).
5. eof: Returns true if the end of a file has been reached, false otherwise.
6. eoln: Returns true if the end of a line has been reached in the standard input, false otherwise.
7. exp: Returns e raised to the power of a given number.
8. ln: Returns the natural logarithm of a number.
9. odd: Returns true if a number is odd, false otherwise.
10. ord: Converts a character to its corresponding integer value.
11. pred: Returns the predecessor of a given ordinal value.
12. round: Rounds a number to the nearest integer.
13. sin: Returns the sine of a number (in radians).
14. sqr: Returns the square of a number.
15. sqrt: Returns the square root of a number.
16. succ: Returns the successor of a given ordinal value.
17. trunc: Truncates a floating-point number to its integer part, removing the fractional part.