Learn ML with Real Code Examples
Updated Nov 20, 2025
Explain
ML supports functional programming paradigms with first-class functions and immutable data structures.
Its type system automatically infers types, reducing runtime errors.
Widely used in academic research, proof assistants, and language development.
Core Features
Let-bindings and recursion
Algebraic data types
Polymorphic functions
Pattern matching in function definitions and case analysis
Module system with signatures, structures, and functors
Basic Concepts Overview
Immutable variables and let-bindings
Recursive function definitions
Pattern matching on data types
Polymorphic types and type inference
Modules and functors for code abstraction
Project Structure
Source file (.ml)
Optional signature files (.mli)
Modules and functor definitions
Test scripts
Documentation and examples
Building Workflow
Define algebraic data types
Write functions using recursion and pattern matching
Use REPL to test small expressions
Organize code into modules
Compile and run larger ML programs
Difficulty Use Cases
Beginner: arithmetic and recursive functions
Intermediate: pattern matching and data structures
Advanced: compiler/interpreter components
Expert: theorem proving and symbolic computation
Comparisons
ML vs Haskell: strict vs lazy evaluation
ML vs Lisp: static vs dynamic typing
ML vs Python: functional vs multi-paradigm scripting
ML vs OCaml: closely related, OCaml adds OO features
ML vs Standard imperative languages: emphasizes immutability and recursion
Versioning Timeline
1973 – ML created as metalanguage for LCF theorem prover
1984 – Standard ML (SML) formalized
1990s – MLton compiler and SML/NJ gained popularity
1996 – OCaml gains traction as ML variant with OO support
2000s–present – ML used in formal methods and compiler research
Glossary
Type inference: compiler determines types automatically
Pattern matching: dispatch based on data structure forms
Functor: module parameterized by another module
Signature: type specification of a module
Algebraic data type: user-defined composite type