yaict/yaict

#!/usr/bin/node

const fs = require("node:fs");

/**
 * The tape of integers
 * @type {number[]}
 */
let tape = [];
/**
 * The current address of the tape being modified
 * 
 * Generally, each function that uses the tape pointer will first
 * progress the pointer by one position.
 */
let tapePointer = 0;
/**
 * A boolean value to determine whether a label is waiting to receive an address
 */
let labelStartActive = false;
/**
 * A dictionary of labels and the line numbers they start at
 */
const labelDictionary = {
    /** Stores labels that haven't had their address found yet */
    _toSet: undefined,
};
/**
 * A dictionary of variables created in the assembly
 */
const variableDictionary = {};
/**
 * The dictionary of opcodes and their values
 */
const OP_CODE_DICTIONARY = {
    ADDITION:               "01",
    MULTIPLY:               "02",
    INPUT:                  "03",
    OUTPUT:                 "04",
    JUMP_IF_TRUE:           "05",
    JUMP_IF_FALSE:          "06",
    LESS_THAN:              "07",
    EQUALS:                 "08",
    MODIFY_RELATIVE_BASE:   "09",
    HALT:                   "99",
};
/**
 * Dictionary of assembly instructions and their associated functions
 */
const ASM_DICTIONARY = {
    "ld": loadToAddress,
    "add": insertArithmetic.bind(null, OP_CODE_DICTIONARY.ADDITION),
    "mult": insertArithmetic.bind(null, OP_CODE_DICTIONARY.MULTIPLY),
    "in": instructionNotYetImplemented.bind(null, "IN"),
    "out": insertOutput,
    "jnz": insertTestJump.bind(null, OP_CODE_DICTIONARY.JUMP_IF_TRUE),
    "jz": insertTestJump.bind(null, OP_CODE_DICTIONARY.JUMP_IF_FALSE),
    "slt": insertLessThanCheck,
    "seq": insertEqualityCheck,
    "incb": instructionNotYetImplemented.bind(null, "INCB"),
    "hlt": insertHalt,
};

/**
 * The main parsing process
 * 
 * @param {string[][]} assembly The array of lines of assembly and their parameters
 */
function transpileAssembly(assembly) {
    for (const line of assembly) {
        let instruction = line.shift();
        // Check if the "instruction" is actually a label start
        if (isLabelStart(instruction)) {
            // Store the label in the dictionary, sans the colon
            labelDictionary._toSet = instruction.substring(0, instruction.length -1);
            labelStartActive = true;
            
            // If the line only contained the label start, continue to the next line
            if (line.length == 0) { continue; }
            // Otherwise, grab the next next string, which must be the instruction
            instruction = line.shift();
        }
        else if (!ASM_DICTIONARY[instruction]) {
            throw new Error(`No function defined for the ${instruction} instruction.`);
        }

        // If a label is waiting to be set, the tape pointer is currently where
        // the next instruction is going to be put, so we can set the label's
        // pointer here
        setLabelStart();

        // Call the function for this instruction, and pass the rest of the line as parameters
        ASM_DICTIONARY[instruction](...line);
    }

    // Replace variables with address
    placeVariables();

    // Clean the values on the tape
    tape = tape.map((inst) => strToDecimal(inst));
}

/* ASSEMBLY HANDLERS */

/**
 * Places a value at a given address on the tape
 *
 * @param {number} address The address to place the value at
 * @param {number} value
 */
function loadToAddress(address, value) {
    if (isVariable(address)) {
        if (!variableDictionary[address]) {
            variableDictionary[address] = {
                value: value,
                address: null,
            };
        } else {
            variableDictionary[address]["value"] = value;
        }
    }
    else {
        tape[strToDecimal(address)] = value;
    }
}

/**
 * Add an arthimetic instruction to the tape
 * 
 * @param {string} opCode The opCode of the arthimetic to perform. Provided by the asmDictionary
 * @param {string} operand1 The first operand for the operation
 * @param {string} operand2 The second operand for the operation
 * @param {string} outputDestination The address to put the result of the operation
 */
function insertArithmetic(opCode, operand1, operand2, outputDestination) {
    if (!isAddress(outputDestination)) {
        throw new WrongParameterModeError();
    }

    // Add the parameter mode for the two operands
    opCode = getParameterMode(operand2) + getParameterMode(operand1) + opCode;

    tape[tapePointer++] = opCode;
    tape[tapePointer++] = operand1;
    tape[tapePointer++] = operand2;
    tape[tapePointer++] = outputDestination;
}

/*
function insertInput() {

}
*/

/**
 * Insert the output instruction onto the tape
 *
 * @param {string} outputParameter The parameter of the value to output. May be an immediate value or an address
 */
function insertOutput(outputParameter) {
    tape[tapePointer++] = getParameterMode(outputParameter) + OP_CODE_DICTIONARY.OUTPUT;
    tape[tapePointer++] = outputParameter;
}

/**
 * Insert a jump instruction based on either a true or false test
 *
 * @param {"05" | "06"} opcode The opcode to execute
 * @param {string} testingParameter The parameter to test. Could be an immediate value or an address
 * @param {string} jumpDestination The address to jump to if the test passes
 */
function insertTestJump(opcode, testingParameter, jumpDestination, offset) {
    tape[tapePointer++] = getParameterMode(jumpDestination) + getParameterMode(testingParameter) + opcode;
    tape[tapePointer++] = testingParameter;
    tape[tapePointer++] = validateJumpDestination(jumpDestination, offset);
}

/**
 * Insert a less than check onto the tape
 *
 * @param {string} operand1 The first parameter to test. Can be either an immediate value or an address
 * @param {string} operand2 The parameter to test against. Can be either an immediate value or an address
 * @param {string} outputDestination The address to write the output to
 */
function insertLessThanCheck(operand1, operand2, outputDestination) {
    if (!isAddress(outputDestination)) {
        throw new WrongParameterModeError();
    }

    tape[tapePointer++] = getParameterMode(operand2) + getParameterMode(operand1) + OP_CODE_DICTIONARY.LESS_THAN;
    tape[tapePointer++] = operand1;
    tape[tapePointer++] = operand2;
    tape[tapePointer++] = outputDestination;
}

/**
 * Insert an equality check onto the tape
 *
 * @param {string} operand1 The first parameter to test. Can be either an immediate value or an address
 * @param {string} operand2 The parameter to test equality against. Can be either an immediate value or an address
 * @param {string} outputDestination The address to write the output to
 */
function insertEqualityCheck(operand1, operand2, outputDestination) {
    if (!isAddress(outputDestination)) {
        throw new WrongParameterModeError();
    }

    tape[tapePointer++] = getParameterMode(operand2) + getParameterMode(operand1) + OP_CODE_DICTIONARY.EQUALS;
    tape[tapePointer++] = operand1;
    tape[tapePointer++] = operand2;
    tape[tapePointer++] = outputDestination;
}

/**
 * Add the HALT opcode at the next address
 */
function insertHalt() {
    tape[tapePointer++] = 99;
}

/* HELPER FUNCTIONS */

/**
 * Places variables in the dictionary on the tape
 * 
 * Places the values loaded into variables at the end of the tape,
 * and stores those addresses.
 */
function placeVariables() {
    // move the tape pointer to the end of the tape
    tapePointer = tape.length;
    for (const variable of Object.keys(variableDictionary)) {
        variableDictionary[variable]["address"] = ++tapePointer;
        tape[tapePointer] = variableDictionary[variable]["value"];
    }
}

/**
 * Check if a given string matches a label start definition
 *
 * @param {string} parameter The parameter to check
 *
 * @returns {boolean}
 */
function isLabelStart(parameter) {
    return /^\w+:$/.test(parameter);
}

/**
 * Confirm that a label exists
 *
 * @param {string} labelName The possible label name to check
 *
 * @returns {boolean}
 */
function validateLabel(labelName) {
    return labelDictionary.hasOwnProperty(labelName);
}

/**
 * Get the address to jump to
 * 
 * @param {string} jumpDestination The destination to jump to. Could be either a memory address or 
 * @param {number} [offset] An offset for the jump destination. Only used if the jump destination is a label
 *
 * @returns {string|number} The address to jump to
 */
function validateJumpDestination(jumpDestination, offset = 0) {
    if (isAddress(jumpDestination)) { return jumpDestination; }
    if (validateLabel(jumpDestination)) {
        return labelDictionary[jumpDestination] + offset
    }
    return;
}

/**
 * Get the memory address a value represents
 *
 * @param {string} parameter A 0d prefixed value
 *
 * @returns {string} The memory address
 */
function isAddress(parameter) {
    return isVariable(parameter) || !!parameter.match(/^0d/);
}

/**
 * Check if a parameter resembles a variable
 *
 * @param {any} parameter 
 * @returns {boolean}
 */
function isVariable(parameter) {
    if (typeof parameter != "string") { return false; }
    return !!parameter.match(/^\@/);
}

/**
 * Get the parameter mode of a parameter for a function
 *
 * @param {string|number} parameter 
 * @returns {"1"|"0"}
 */
function getParameterMode(parameter) {
    return isAddress(parameter) ? "0" : "1";
}

/**
 * Convert a string to a base 10 integer
 *
 * @param {string} decimalValue
 * @returns {number}
 */
function strToDecimal(decimalValue) {
    if (typeof decimalValue == "number") {
        return decimalValue;
    }

    if (isVariable(decimalValue)) { return variableDictionary[decimalValue]["address"]; }

    return parseInt(decimalValue.replace(/^0d/, ""), 10);
}

/**
 * Alert that the opcode called hasn't been implemented yet
 *
 * @param {string} instruction
 */
function instructionNotYetImplemented(instruction) {
    throw new Error(`The ${instruction} instruction has not yet been implemented`);
}

/**
 * Assigns a label waiting an address to the current pointer position
 * 
 * @returns {void}
 */
function setLabelStart() {
    if (labelDictionary._toSet === undefined) { return };

    labelDictionary[labelDictionary._toSet] = tapePointer;
    labelDictionary._toSet = undefined;
}

/* MAIN FUNCTIONALITY */

/**
 * Read a file of IntCode Assembly
 *
 * @param {string} filename The name of the file to read
 *
 * @returns {string[][]} An array of assembly instructions
 */
function readFile(filename) {
    let instructions = fs.readFileSync(filename, "utf8");

    instructions = instructions.split("\n")
        // Remove comments and trailing spaces
        .map((line) => line.replace(/\s*(?:\/\/.+)?$/, ""))
        // Filter out empty lines
        .filter((line) => !!line)
        // Split each line into an array of parameters
        .map((line) => line.split(/,? /))
        // Find label markers;

    return Array.from(instructions);
}

function main() {
    const ret = readFile(process.argv[2]);

    console.log("Assembly provided: ", ret);

    console.log("Parsing assembly...");

    transpileAssembly(ret);

    console.log("Parsed IntCode: ", tape.join(", "));

    console.log("Labels:", labelDictionary);
}

main();

class WrongParameterModeError extends Error {
    constructor() {
        super("This parameter for this function is in the wrong parameter mode");
    }
}