Functional Programming

Independentwork №4

Done by: Rasulov A

Checked by: Karshieva T

Karshi branch of the Tashkent University of Information Technologies named after Muhammad Al – Khorazmi

Evolution of Languages

• 1940’s: connecting wires to represent 0’s and 1’s
• 1950’s: assemblers, FORTRAN, COBOL, LISP
• 1960’s: ALGOL, BCPL (→ B → C), SIMULA
• 1970’s: Prolog, FP, ML, Miranda
• 1980’s: Eiffel, C++
• 1990’s: Haskell, Java, Python
• 2000’s: D, C#, Spec#, F#, X10, Fortress, Scala, Ruby, . . .
• 2010’s: Agda, Coq
• . . .

Evolution has been and is toward higher level of abstraction

Implementing a Programming Language – How to Undo the Abstraction

Source
program
Lexer
Parser
Type
checker
Interpreter
Optimizer
Code
generator
Machine code
Bytecode
Machine
Virtual machine
I/O
JIT
I/O
I/O

Compiling and Interpreting (2)

• Borderline between interpretation and compilation not clear (not that important either)
• Same goes with machine code vs. byte code.
• Examples of modern compiling/interpreting/executing scenarios:
• C and C++ can be compiled to LLVM bytecode
• Java compiled to bytecode, bytecode interpreted by JVM, unless it is first JITted to native code, which can then be run on a virtual machine such as VMWare

Lexical Analysis

From a stream of characters

if (a == b) return;

to a stream of tokens

keyword[‘if‘]

symbol[‘(‘]

identifier[‘a‘]

symbol[‘==‘]

identifier[‘b‘]

symbol[‘)‘]

keyword[‘return‘]

symbol[‘;‘]

Syntactic Analysis (Parsing)

From a stream of characters

if (a == b) return;

to a stream of tokens

keyword[‘if‘]