Programming Languages Test 1

Syntax is the form or structure of expressions, statements, and program units.

Semantics is the meaning of expressions, statements, and program units.

Syntax and semantics together define a programming language.

A lexeme is the lowest-level syntactic unit of a language, such as a symbol or keyword.

A token is a category of lexemes, like identifiers or operators.

A recognizer reads input strings and determines if they belong to the language.

Noam Chomsky developed Context-Free Grammars in the mid-1950s.

BNF is a notation used to describe the syntax of programming languages.

Non-terminal symbols in BNF are abstractions representing syntactic structures.

A derivation is a repeated application of rules starting with the start symbol, leading to a sentence.

A sentential form is any string of symbols in a derivation process.

A grammar is ambiguous if it generates a sentential form with two or more distinct parse trees.

The three primary methods of semantics description are operational, denotational, and axiomatic.

To increase the ability to express ideas, choose appropriate languages, and improve learning and implementation of languages.

They require large numbers of floating point computations and use arrays, often in Fortran.

They produce reports and use decimal numbers and characters, commonly in COBOL.

Efficiency is crucial due to the continuous use of system resources.

LISP is frequently used in artificial intelligence for manipulating symbols rather than numbers.

Readability, writability, reliability, and cost.

It depends on simplicity, orthogonality, data types, and syntax considerations.

Writability refers to how easily a language can be used to create programs, relying on simplicity, abstraction, and expressivity.

Reliability refers to a language’s conformance to specifications and its ability to avoid errors through type checking and exception handling.

Compilation, pure interpretation, and hybrid implementation.

It is a computer architecture where data and programs are stored in memory, with instructions and data piped from memory to the CPU.

It refers to the limited connection speed between a computer's memory and processor, which restricts computing speed.

They initially translate programs to an intermediate language and then compile it to machine code during execution, as used in Java and .NET.

It is a collection of tools used for software development, such as UNIX or Microsoft Visual Studio.

Balancing reliability, cost, readability, and writability.

It was designed in 1945 but not published until 1972, and featured advanced data structures like floating-point arrays and records.

Pseudocodes improved readability, modifiability, and addressed the limitations of machine code, like the lack of indexing and floating-point operations.

Fortran was designed for scientific applications, emphasizing machine efficiency and array handling, without string or decimal handling.

Fortran I was the first implemented version of Fortran, introduced in 1957, and was known for post-test loops and fast code.

Fortran 77 introduced character string handling, logical loop control, and the IF-THEN-ELSE statement.

LISP, designed for AI research, is a functional language that processes data in lists rather than arrays and uses symbolic computation.

LISP only has two data types: atoms and lists.

ALGOL 60 was the first machine-independent language, with a block structure and formal syntax definition using BNF.

COBOL was based on FLOW-MATIC and used for business applications, featuring English-like syntax and separate data and code.

BASIC was designed for non-science students, aiming to be easy to learn and use, with fast homework turnaround and time-sharing capabilities.

PL/I combined features of scientific and business computing, designed by IBM to support both types of applications.

Both APL and SNOBOL had dynamic typing and storage allocation, with APL excelling in array operations and SNOBOL in string pattern matching.

SIMULA 67 introduced classes, objects, inheritance, and coroutines, pioneering data abstraction.

ALGOL 68 influenced Pascal, which became widely used for teaching structured programming.

Java is an object-oriented language based on C++, known for eliminating unsafe features and supporting concurrency, applets, and portability.

C# combines features from C++, Java, and Delphi, evolving rapidly as part of the .NET platform.

Scripting languages like Perl, PHP, and Python are often used for web development, with client-side or server-side processing.