Week 3

Notes from Zain

Compilation process

Forgot first one (slide 21)

Syntax analyzer:

Checks syntax and grammar if its part of the PL. Creates a parse tree or abstract syntax tree (AST). Output: Shows statement order, block structure.

Semantic analysis:

Checks type checking error (undeclared variables or functions) and scope rules and makes sure operations make sense. (Cant add integer to string) Output: a verified AST with no semantic errors (if any errors found the compiler will produce with an error message)

Optimization:

Removes redundant operations, simplifies expressions and applies other optimizations. Output: optimized version of the code.

Code generation:

Translates optimized intermediate representation into machine code or assembly language.

Assembly:

Converts the assembly code into machine code (binary).

Linking:

Replaces function names and variables names with memory addresses and combines separate object files into one executable. Output: Final executable file. (.exe on Windows, or a binary file on Linux/Unix)

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Interpretation process

Will translate the entire program into machine
code beforehand, line by line.

• easier debugging
• more memory efficient
• slower program

Lexical Analysis (Tokenization)

Breaks down source code into tokens. Tokens are smallest units of meaning in the language such as keywords operations identifiers and literals.

Parsing (Syntax Analysis)

Checks sequence of tokens to ensure syntax is correct. Builds a parse tree that represents the logical structure of the program.

Semantic Analysis

Checks if the programs logic is correct.

Execution

The interpreter executes the code directly. The interpreter does not generate separate machine code file like a compiler, instead it executes code immediately.

Runtime Errors and Feedback

since the process is line by line it can encounter runtimes errors during execution. if it runs into an error it reports it immediately.

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Hybrid process

hybrid process is context of PLs that use both compilation and interpretation to execute a program Uses advantages of both compiling (efficient optimized machine code) and interpreting (blah blah).
Hybrid has two major components: Compilation and Interpretation.
Steps:

• Compilation to Intermediate code (Bytecode)
• Execution by Virtual Machine (VM)
• Just-In-Time (JIT) Compilation (Optional Optimization):
  improves performance.

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Compiler vs interpreter

Check slide: 39 & 40

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Java example

java is compiled before program runs. If there is an error, the compiler will stop and report it, but the program won’t execute.

public class Main {
	public static void main(String[] args) {
		int x = 10;
		int y = "text";
		System.out.println(x + y);
    }
}

Python example

In python (interpreted language), the program is executed line by line. Errors are caught as the code is executed. Error below is a runtime error.

print("Hello World")
x = 10
10 y = "text"
print(x + y)

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Programming environments

Integrated Development Environment (IDE):

Comprehensive suit of tools like code editor, compiler, debugger and other utilities to support development process.

• Visual Studio
  For .NET and C++
• Eclipse
  For Java
• PyCharm
  For Python

Text Editors:

Lightweight tools used for writing code. not feature-rich like IDEs but can be customized with plugins for language specific features.

• Sublime Text
• Atom
• Notepad+++

Command Line Interface (CLI):

interface used for executing programs, running scripts, using version control system.

• Bash (Unix)
• PowerShell (Windows)
• Terminal (MacOS)

Online/Cloud Based:

Run code directly from a browser. These environments often offer collaborative features and eliminate need for setting up local development tools.

• Repl.it
• GitHub Codespaces
• Google Colab (for Python)

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