Data Types

• atoms
  • true, hello, 'WORLD'
• binary
  • <<"Hello World">>
  • Useful for unicode characters
• lists
  • [1,2,3]
  • "Hello, World" (a string of characters [which are just integers])
• tuples
  • {greeting, <<"Hello there!">>}
• integers
  • 12345
  • max value of ram

Pattern Matching

• Single assignment variables start with an uppercase character
• The = operator
  • A = 10.
  • {RecordType, Car} = {car, "Challenger"}.
  • Message = "Hello, world!".

Lists

• map (just like ruby map)
• filter (just like ruby select)
• List comprehension (map)
  • A = [1,2,3,4,5].
  • [X * 2 || X <- A].
  • [2,4,6,8,10]
• List comprehension (filter)
  • A = [1,2,3,4,5].
  • [X || X <- A, X rem 2 == 0]
• Build in reverse for constant time list insertion the use lists:reverse(List).

Functions

• Arity (number of parameters a function takes)

Recursions

• call function in tail position to reuse call frame (bindings)
• last call in function is "tail"

Processes

• Module and Process are useful for code decomposition
• Akin to a Class

Misc

• erlc (to compile .erl to .beam)
• erl -pa (for load path)
• m(module_name) gives info about module
• c("/path/to/file.erl") or c(demo) to compile
• _Variable (ignore variable)

Line terminators

• Comma separates sequentially executing statements (,)

  • X = 2, X1 = X+2, X2 = X1 + 2.

• Semicolon separates related but distinct things (;)

  • see even_or_odd

• Period terminates a block of things or a single thing (.)