How To Convert Python Source Code To Bytecode

The function compile() is a built-in function in Python that is used to compile source code into bytecode or code object. In this article, I will tell you how to use the compile function to convert python source code into bytecode with examples.

1. Python compile() Function Definition.

  1. The compile() function returns a code object that can be executed by the exec() function, evaluated by the eval() function, or interactively executed by the interact() function.
  2. The syntax for compile() function is:
    compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
  3. source is the source code to be compiled. It can be a string, a code object, or a file object.
  4. filename is the name of the file from which the code was read. If the code is not read from a file, you can pass an arbitrary string as the filename.
  5. mode specifies the mode in which the code should be compiled. It can be one of the following three strings:
    'exec': If you want to compile a module-level code or a code block that doesn't return a value.
    'eval': If you want to compile a single expression that returns a value.
    'single': If you want to compile a single interactive statement.
  6. flags is an optional parameter that can be used to specify additional compiler flags. You can use bitwise OR (|) to combine multiple flags.
  7. dont_inherit is an optional boolean parameter that specifies whether to inherit the compiler flags from the current scope (False) or to use a fresh set of flags (True).
  8. optimize is an optional integer parameter that specifies the optimization level of the compiler. The default value is -1, which means that the compiler will use the default optimization level.

2. How To Use Python compile() Function To Convert Python Code To Bytecode Examples.

  1. Here are some examples that demonstrate how to use the compile() function in Python.

2.1 Compile a string and execute it using exec().

  1. Below is the example source code.
    code_str = 'print("Hello, World!")'
    code_obj = compile(code_str, '<string>', 'exec')
    exec(code_obj)  # Output: Hello, World!
  2. When you run the above code, it will output the below message on the screen.
    Hello, World!
  3. In this example, we first create a string containing the Python code that we want to compile.
  4. We then use the compile() function to compile the code string into a code object.
  5. Finally, we use the exec() function to execute the compiled code.

2.2 Compile a string and evaluate it using eval().

  1. Below is the example source code.
    code_str = '123 * 456'
    code_obj = compile(code_str, '', 'eval')
    result = eval(code_obj)
  2. When you run the above code, it will output the number 56088 (123 * 456) on the screen.
  3. In this example, we use the eval() function to evaluate the compiled code and print the result.

2.3 Compile a string with additional compiler flags.

  1. Below is the example source code.
    import ast
    code_str = 'print("Hello, World!")'
    code_obj = compile(code_str, '<string>', 'exec', flags=ast.PyCF_ALLOW_TOP_LEVEL_AWAIT)
    exec(code_obj)  # Output: Hello, World!
  2. In this example, we use the ast module to specify an additional compiler flag PyCF_ALLOW_TOP_LEVEL_AWAIT.
  3. This flag allows the use of top-level await statements in the compiled code.
  4. We then compile the code string using the compile() function, specifying the additional flag, and execute it using the exec() function.
  5. You should first import the ast module use the import ast command, otherwise, it will throw the error NameError: name ‘ast’ is not defined.

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