A simple compiler for a custom language and computer simulator. This project is only made for educational use, to roughly demonstrate how a program code is compiled and ran in the computer. However, the inner workings of the compiler does not represent a real-world compiler -- it is just enough to translate a program code into machine code.

If you ran into any bugs or problems, or even just a question, please open an issue.

To run the program, simply download the provided release and run it. You can also run the following command:

# Make sure that the jar is present in the current working directory $ java -jar compiler.jar

Instructions to build the project are currently not available.

The first tab is the code editor. Once the program is compiled, the rest of the tabs will contain the compilation result.

Valid variable identifiers must match the regex [A-Za-z_][A-Za-z0-9_]*. It is important to note that all of these can only contain 4-byte unsigned integers.

This tells the program that the given variable exists. Doin so allocates 4 bytes of memory, and adds the identifier to the symbol table.

var <identifier> // For example: var abcd123 var _abc // Invalid syntax: var 123abc

On the current version, shorthand for multiple instantiations is not supported.

// Generates compile error var var1, var2, var3

Once a variable is instantiated, its content can be changed later in the program. An undeclared variable will of course generate a compile error, since it is not found on the symbol table.

The usage of complex arithmetic expressions on the right-hand side of an assignment is supported.

Supported operations in arithmetic: + - * /

<varname> = <arithmetic> var a var b a = 5 + 7 b = a + 10

The compiler also supports variable initialization.

var <varname> = <arithmetic> var c = 10 + a * (7 - b) / 2 // assuming the variables declared in the previous // example are in the same program

Once a variable is declared, it cannot be redeclared later (this will generate a compile error!).

var abcd = 5 var abcd // compile error!

The compiler supports the usage of arrays.

var <arrname>[<length_in_number>] // For example: var arr[10]

Array declaration is still limited, causing the following examples to generate compile errors.

// All of these generate compile errors var arr[] // length must be specified var arr[10 + 5] // length should strictly be a number var a = 5 var arr[a] // length cannot be inferred from another variable

Just like variable assignment, an array element can be assigned with the return value of an arithmetic expression. However, accessing an array can only be done using a strictly numerical index.

<arrname>[<index-in-number>] = <arithmetic> var arr[10] var a = 10 var b = 1 arr[0] = 10 + 5 * (a - 3 * b + arr[1]) // These will generate compile errors arr[1 + 2] = 5 // usage of arithmetic as index arr[b] = 5 // usage of variable as index

Unfortunately, unlike single variables, initializing an array with a list is not supported.

var a[5] = {1, 2, 3, 4, 5} // not supported

An array element can be accessed as a part of an arithemtic expression. However, just like before, they can only be accessed with a strictly numerical index.

var arr[5] var b = 3 arr[0] = b var arr[1] = arr[0] * 5 // These will generate compile errors var c = arr[1 + 2] // usage of arithmetic as index var d = arr[arr[0]] // usage of array element as index var e = arr[b] // usage of variable as index

The compiler supports complex boolean expressions. These can be put as a condition for if/else or while statements.

var a = 5 var b = 7 !(a + b > 5) && false || (true == false) && (5 <= b) && (5 != 6 + 7)

Supported logical operations include:

• Logical: negation !, conjunction &&, disjunction ||
• Comparison: < > <= >= == !=

The compiler supports if/else statements.

if (<condition>) // code endif if (<condition>) // code else // code endif

Limitation: else if statements not supported

The compiler also supports while statements.

while(<condition>) // code endwhile

The compiler is very much limited:

• for and do while unsupported
• negative numbers unsupported
• basic operators such as ++ -- % unsupported
• functions unsupported
• ternary operator not supported
• string unsupported
• all data types are 4 byte unsigned int

• Nicky Logan
• Madeleine J.
• Nadya F. Bachtiar
• Barjuan Davis

See the list of contributors for this project here

• Dr. Sutrisno, S.E., M.Kom. for the computer simulator code
• All external dependencies used in this project