How Type Handling Distinguishes a Programming Language
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  • Writer's pictureEthan Paoletti
    • Dec 28, 2023
    • 8 min read

How Type Handling Distinguishes a Programming Language

Updated: Jan 22


Welcome back to our ongoing exploration of software programming languages. In this third installment, we'll delve into a critical aspect that sets languages apart: type handling. While our earlier discussions covered language levels and programming paradigms—essentially the architectural frameworks of programming languages—today, our focus shifts to defining how each programming language handles data types. We'll explore how these nuances differentiate each language and profoundly impact a software developer's workflow.

By the end of this article, complementing our previous articles, you'll be able to discern languages not just by their readability, development speed, or hardware control but also by how they architecturally frame their data. These three articles collectively serve as a comprehensive groundwork for upcoming discussions, including language-specific career pathways and the anticipated software language trends as we approach 2024.

Disclaimer: This information is provided for educational purposes only. Please research and confirm any information before making any career decisions.

Table of Contents

Understanding Type Handling

Understanding how programming languages handle data is essential for robust software development. The type system of a language, responsible for data organization, wields significant influence. This includes strong vs. weak type handling, static vs. dynamic type handling, and type safety.

Definitions

Language Type

In programming languages, a "type" refers to a classification system that defines the kind of data that a variable can hold or the operation that can be performed on it. It sets constraints on the values that a particular entity - such as a variable or object - can take. Types can range from basic data types like integers, float point numbers, double precision numbers, characters, and strings to more complex structures like arrays, objects, functions, or user-defined types. The type of an entity determines the operations that can be performed on it, helps in error detection during compilation or runtime, and aids in maintaining data integrity and program correctness.

Variables: Basic Data Labels

Variables are labels attached to specific data stored within a computer's memory and are pivotal for keeping the data organized within a program. Their primary function involves encapsulating a diverse spectrum of information, ranging from basic numerical values and text to intricate and multifaceted data structures. Essentially, these elements are responsible for storing and organizing data within the context of a computer program.


Geometric Equations: Examples of Variable Usage
Geometric Equations: Examples of Variable Usage - Credit Gerd Altmann from Pixabay

Objects: Packs of Data

Objects are a way to group related variables and their functionalities. They encapsulate both variables and operations, facilitating actions such as accessing variables, modifying variables, duplicating variables, executing calculations, and more. The key takeaway about these objects is that they define a specific type and are managed similarly to the predefined variable types within the programming language. While we'll keep the definition concise for this article, the concept of objects will be explored in more detail in a subsequent article.


Explicit vs. Implicit Type Declarations

Explicit type declarations in programming involve expressly stating the data type of variables within the code, leaving no room for assumptions or ambiguity. This method explicitly spells out the data type, providing clarity to both the programmer and the system executing the code. Implicit type declarations, on the other hand, occur when the programming language infers or assumes the data type of a variable without explicitly mentioning it in the code. It's akin to dropping hints or allowing the system to deduce the type based on the assigned value or contextual information without direct specification. This approach often streamlines coding by reducing verbosity and allowing for more concise and readable code.

Implicit Type Declaration:

x = 2;

Explicit Type Declaration:

int x = 2;

Type Handling Classifications

Strong and Weak Typing

In the world of programming languages, the terms "strongly typed" and "weakly typed" often pop up in discussions about how these languages handle data. Strongly typed languages prioritize stringent enforcement of data types, while weakly typed languages provide more flexibility in handling types during program execution.

However, classifying a language as strictly "strongly" or "weakly" typed is not always straightforward. Many of us have considered C++ a strongly typed language because it demands that you clearly label data types while writing code. That's what I used to say in all my interviews, and most engineers I have met agreed. It's like giving each piece of info a specific box to fit into, and once the code is set, these boxes don't change.

However, there's another school of thought that says C++ leans towards being weakly typed. The argument here is about it allowing relatively easy type conversion without explicitly stating the intended type. Some programmers argue that this flexibility, while convenient, can cause problems by shoving data into the wrong boxes and creating errors. We'll explore this further when discussing type conversion later in this article.

This discussion isn't confined to C++; it extends to many other programming languages. That's why, instead of boxing languages as strictly "strong" or "weak," it's more productive to focus on practical aspects. We'll discuss concepts like type safety – how secure and reliable the types are – and whether a language figures out types before running the code (statically typed) or while it's running (dynamically typed). By examining these concrete aspects, we can better understand how these languages operate in the real coding world, steering away from generalized classifications toward a more practical understanding.

Type Safety

Language type safety encompasses various mechanisms in programming languages to ensure data integrity and minimize errors arising from mismatched data types. This includes various mechanisms such as type inference, type constraints, type conversion, and type checking. These mechanisms are put in place by the creators of the language and are ultimately implemented in a programming language to ensure the safe handling of the creation of data, the conversion of data, and the quality control of data as it is handled throughout a program's runtime.


Type Inference

Type inference is a feature of some programming languages that allows a programmer to assign data to a variable, such as x = 3, without explicitly assigning what type it is. Later, the compiler or interpreter will infer the variable type from the data the programmer assigned to it. In the case of the example above, x = 3, the compiler would automatically assign the variable as an integer. Certain programming languages, such as Swift and Kotlin, implement type inference. This clever mechanism results in more streamlined, readable, and succinct code and increases writing speed.

On the flip side, some languages demand explicit type declarations for variables. For example, in C, you must write int x = 3 to assign the variable as an integer. This ensures an immediate and explicit understanding of what type a variable is at the time it is written by the programmer. Despite appearing more verbose, this explicit approach boosts code clarity by maintaining precision in defining variable types across the entire code base, potentially enhancing code safety and reliability.

I want to highlight that in languages emphasizing type inference without pre-runtime type checking, programmers often need to manually insert numerous error-checking statements across larger codebases. This is necessary to guarantee the correct passage of types between different areas of the code. Consequently, in such scenarios, the reduction in code verbosity, offered by type inference, can become insignificant. Understanding this distinction is crucial in discerning why certain languages excel in scalable software development, a topic we'll delve deeper into in our forthcoming article discussing how programming languages align with specific career paths.

The choice between utilizing type inference or opting for explicit type declarations often hinges on striking a balance between crafting concise code and ensuring upfront clarity regarding specified variable types. Certain programming languages, such as Rust and C#, allow for both type inference and explicit type declarations.

Code Safety
Code Safety - Credit Darwin Laganzon from Pixabay

Type Conversion

Type conversion refers to a feature within a programming language that allows for one type to be converted into another type directly or indirectly, such as within a mathematical expression. For example, float y = 3.2/x, where x is an integer, will implicitly convert x into a float. Languages such as C++ prioritize implicit type conversion. Other languages, like Python, emphasize explicit type conversion through a feature called casting. Explicit type casting refers to a function-based type conversion where the programmer hands the variable to a predefined function used to tell the language how and which type to convert a variable to. An example of this would be float y = 3.2/(float)x, where x is an integer and (float) is the function used to explicitly convert x into a float.

The choice between explicit and implicit type conversion impacts a language's predictability and type error likelihood. As we stated above, explicitness enhances clarity but can be more verbose, while implicitness offers convenience but might lead to unexpected behavior. Understanding these differences helps developers navigate a language's control over data integrity which impacts type safety.

Type Constraints

Type constraints are essentially rules imposed by a programming language on various variables. For instance, in some programming languages, if you attempt to divide an integer by zero, the code won't compile. These constraints act as guardians, preventing certain actions or operations that could lead to errors or unexpected behavior in the program. It's worth noting that while specific constraints might vary from one language to another, the concept itself is quite universal across modern programming languages. Some languages may have stricter constraints than others, defining a clearer set of rules governing what operations are allowed or disallowed. Other languages may simply present the programmer with a warning if they try to use a variable in a manner that it should not be used.


The landscape of type constraints constantly evolves as programming languages advance to newer versions. Language designers regularly incorporate new constraints, often in response to identified errors or to enhance the language's robustness and reliability. However, though an important subject when discussing type safety, discussing type constraints alone might not serve as a reliable differentiator between programming languages, since they are prevalent and varied in most modern languages.


Type Checking

Type checking is a feature that rigorously validates data types, ensuring strict adherence to predefined types. In programming languages, a robust type checking mechanism is used during either compilation or runtime. This process minimizes type errors, contributing significantly to code reliability and maintaining data consistency throughout the program's execution.


Static and Dynamic Type Handling

Among the various mechanisms employed by programming languages to uphold type safety, type checking is the one that drastically sets each language apart. Within type checking there are two distinct approaches: statically typed and dynamically typed languages.

Statically typed languages perform type-checking during the compilation phase of code. This means that, right from the start, they establish and enforce strict rules regarding variable types. This upfront scrutiny ensures that variables adhere to their declared types, creating a sturdy groundwork for the program's execution.

On the other hand, dynamically typed languages take a different approach by deferring type checks until runtime. This grants developers more flexibility in handling variable types during the implementation phase. It allows for on-the-fly changes to variable types, making the programming experience more fluid. However, this flexibility comes with a trade-off: when a type error occurs in a dynamically typed language during runtime, an error that might have been caught in a statically typed language before the program ever ran, leads to an exception (a runtime error). This often causes the program to crash, displaying an error to the user.

Understanding how programming languages handle types empowers developers to choose languages that best suit their project requirements. This knowledge enhances code quality and contributes to building stronger, more tailored software solutions.

Type Handling Summary Table

Use this table for a quick-glance summary of many of the most popular programming languages and how type-handling methods differentiate them:

Language

Type Inference

Implicit Type Conversion Allowed

Type Checking

AspectJ

Yes

No (but allowed through Java)

Statically Typed

C

No

Yes

Statically Typed

C#

Yes

Yes

Statically Typed

C++

Limited

Yes

Statically Typed

Elixir

Yes

Limited

Dynamically Typed

Go

Yes

No

Statically Typed

Haskell

Yes

No

Statically Typed

HTML

N/A

N/A

N/A (Markup Language)

Java

Yes

Yes

Statically Typed

JavaScript

Yes

Yes

Dynamically Typed

Kotlin

Yes

No

Statically Typed

Python

Yes

Yes

Dynamically Typed

R

Yes

Yes

Dynamically Typed

Ruby

Yes

Yes

Dynamically Typed

Rust

Yes

Limited

Statically Typed

Scala

Yes

No

Statically Typed

SQL

N/A

N/A

N/A (Query Language)

Swift

Yes

Limited

Statically Typed

Wrapping Things Up

In wrapping up our discussion on language type handling, we've explored the debates about strong versus weakly typed languages, stressed the importance of type safety, and highlighted the distinctions between static and dynamic type handling. This discussion sheds light on the diversity found among programming languages. Looking ahead, our next chapter will explore different career paths aligned with specific languages. After that, we'll take a closer look at the evolving trends influencing software languages as we head into 2024, concluding our comprehensive series on software programming languages.


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