Pascal

Pascal holds a special place in computing history as the language that taught a generation of programmers the principles of structured programming. Designed with clarity and discipline in mind, Pascal proved that code could be both readable and efficient.

History & Origins

In the late 1960s, Niklaus Wirth at ETH Zürich was dissatisfied with the complexity of ALGOL 68. He set out to create a smaller, more elegant language that would be suitable for teaching programming while remaining powerful enough for practical use.

Named after the French mathematician and philosopher Blaise Pascal, the language was published in 1970. Wirth’s design goals were clear:

1. Educational clarity - Easy to learn and teach
2. Structured programming - Enforce good programming habits
3. Strong typing - Catch errors at compile time
4. Efficient compilation - Fast compilation to encourage experimentation

The Turbo Pascal Revolution

While academic Pascal implementations were useful for teaching, Borland’s Turbo Pascal (1983) changed everything. For just $49.95, developers got:

• A blazingly fast compiler (compile times measured in seconds)
• An integrated editor
• Excellent error messages
• Small executable sizes

This was revolutionary when competitors cost thousands of dollars and took minutes to compile. Turbo Pascal democratized programming and created a generation of Pascal developers.

Why Pascal Still Matters

1. Teaching Structured Programming

Pascal’s strict enforcement of declaring variables before use, its clear block structure, and its readable syntax make it an excellent teaching language. Many computer science programs still use Pascal or Pascal-derived languages.

2. Delphi and RAD Development

Object Pascal (Delphi) remains one of the most productive environments for building Windows applications. Its visual form designer and component-based architecture influenced many later tools, including Visual Basic, C# Windows Forms, and modern IDEs.

3. Cross-Platform Development

Modern Pascal tools like Free Pascal and Lazarus provide true cross-platform development:

• Windows, macOS, Linux, FreeBSD
• iOS and Android
• Embedded systems (ARM, AVR)
• WebAssembly (experimental)

Pascal Dialects

Several Pascal variants exist today:

Modern Pascal Compilers

Free Pascal (FPC)

The open-source compiler supporting multiple platforms and Pascal dialects:

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# Install on macOS
brew install fpc

# Install on Ubuntu/Debian
sudo apt install fpc

# Compile and run
fpc hello.pas
./hello

Lazarus IDE

A Delphi-compatible RAD IDE built on Free Pascal:

• Visual form designer
• Component library (LCL)
• Cross-platform GUI development
• Free and open-source

Delphi (Commercial)

Embarcadero’s commercial IDE:

• Professional RAD environment
• FireMonkey cross-platform framework
• Enterprise database tools
• Active development and support

Language Features

Pascal introduced or popularized many features now common in programming:

program Features;

type
    // Enumerated types
    Color = (Red, Green, Blue);

    // Record types (like structs)
    Person = record
        Name: string;
        Age: Integer;
    end;

    // Set types
    CharSet = set of Char;

var
    c: Color;
    p: Person;
    vowels: CharSet;

begin
    c := Blue;
    p.Name := 'Alice';
    p.Age := 30;
    vowels := ['A', 'E', 'I', 'O', 'U'];

    if 'A' in vowels then
        WriteLn('A is a vowel');
end.

Getting Started

Pascal code is stored in .pas files. The basic structure:

program ProgramName;

{ Declarations go here }

begin
    { Main code goes here }
end.

Continue to the Hello World tutorial to write your first Pascal program.