Causes The ‘unexpected end-of-input’ Error in Ruby Program?

This Ruby code defines a CommandModel class that accepts an array (raw) and initializes the raw and len attributes, with a method write_cmd to output a command string. The SomeCommand class inherits from CommandModel, allowing it to pass the raw

Ruby Code (with Errors):

codeclass CommandModel 
    attr_reader :raw
    attr_reader :len

    def initialize(raw)
        fail TypeError unless raw.is_a?(Array)
        @raw = raw
        @len = raw.length
    end

    def write_cmd
        cmd(
            "UUT PAYLOAD_WRITE with CCSDS_AP_ID 1, "\
            "LENGTH #{@len}, "\
            "RAW_BYTES #{@raw}")
    end
end

class SomeCommand < CommandModel
    def initialize(raw)
        super(raw)
    end
end

Mycmd = SomeCommand.new([0x01, 0x02, 0x03])
Mycmd.write_cmd()

What’s Wrong with My Code? | Ruby

At first glance, the provided Ruby code defines a CommandModel class to handle some payload data and a child class SomeCommand to extend it. However, when running the code, an error is likely to occur because of a missing method and a possible misunderstanding about how certain elements function.

Error: Undefined Method cmd

The method write_cmd calls cmd, but the method cmd is not defined in the code. Ruby will throw a NoMethodError because it does not know what cmd refers to. You’ll need to define this method or replace it with a proper output method like puts if the intent is to print the result.

Error: Naming Conventions

While this isn’t a hard error, Mycmd does not follow the Ruby naming convention for variables. Variables should be written in snake_case, so it’s better to name it my_cmd.

Fix:

• Replace the cmd method call with puts or define cmd if needed.
• Rename Mycmd to my_cmd for better readability.

Here’s the corrected code:

Corrected Code:

codeclass CommandModel 
    attr_reader :raw, :len

    def initialize(raw)
        fail TypeError unless raw.is_a?(Array)
        @raw = raw
        @len = raw.length
    end

    def write_cmd
        puts(
            "UUT PAYLOAD_WRITE with CCSDS_AP_ID 1, "\
            "LENGTH #{@len}, "\
            "RAW_BYTES #{@raw}"
        )
    end
end

class SomeCommand < CommandModel
    def initialize(raw)
        super(raw)
    end
end

my_cmd = SomeCommand.new([0x01, 0x02, 0x03])
my_cmd.write_cmd()

Summary:

After these changes, the code will run without issues and correctly output the shape details with the provided input.

The error occurred due to calling an undefined cmd method. This has been replaced with puts to print the output.

Following Ruby’s naming convention, Mycmd has been renamed to my_cmd to ensure clean and maintainable code.