Is Haskell case sensitive ?

(Note:  We may earn commissions from products/services you click on.  This is at no extra cost to you.)

Table of Contents

Haskell is a case-sensitive programming language because functions must begin with capital letters. By contrast, types must start with an upper case letter. However, it is essential to note that in Haskell, the capitalization of the identifier usually encodes information about semantics.

While this flexibility is highly admirable, it can prove quite a challenge to beginner developers. A single mistype can cause a great deal of change in the entire program – it can alter the intent of a code piece or make the program run the way it was intended. That means dealing with case-sensitive codes requires a deeper understanding of coding, so it is easy and possible to type everything correctly.

For writing lettered characters, upper case letters were initially the standard way. These letters are distinguished because of their standard and height. Lower case letters came much later, and they have different heights – for example, in height – h ascends while g descends.
The topic of case sensitivity is quite broad and touches on different aspects differently. Its application in programming languages may differ from others, such as file systems and text searches. So, there are additional requirements when it comes to case sensitivity/insensitivity.
Keep in mind that case insensitive programs have recognizable functions, classes, and declarations, which code writers can easily understand. However, a few programmers find the aspect of case sensitivity helpful in their programs, which opposite to the other group that finds it a terrible idea.

is Haskell case sensitive

In Data.Text values suggest comparing the various requirement for case sensitivity, especially when using NLP tasks. While searching tokens for information extraction tasks, you can search based on either standard string quality or equality relationship. The equality relationship route is less restrictive. 

Take a positive step and enhance your career.  Click this affiliate link to register for Data Science Certification Training.

Case sensitivity is among the commonest changes; however, it’s often a function of a specific token. Usually, a term like “activate” might be in lower case. Nevertheless, if it is the first term in a sentence, it should start with a leading capital. Similarly, if it is used in the title text, it may all be in upper case. Sometimes capitalization mid-sentence may be needed. Therefore, comparisons ignoring cases make sense. On the other hand, acronyms such as the US have different semantic depending on capitalization. 

It might be impossible to create a type-class wrapper for specific equality classes as they are value-driven aspects. In this case, a case insensitive package seems like it wouldn’t work. You can use toLower to make canonical representation and compare the representations to create custom versions of text comparison functions that consider text sensitivity. 

A Better Way: Perhaps toCaseFold might work better than the toLower for case insensitive comparisons. 

Unicode Characters

Comparing alphabetical and non-alphabetical, a symbol or control character isn’t well understood and is a bit of a minefield. That makes ordinal comparisons quite tricky. One-to-one mapping between lower case and upper case in Unicode characters isn’t possible; therefore, character comparison at a time doesn’t make the comparison valid. Worse, some applications might order differently – for instance, ordering “Apple” ahead of “apple.” Still, others may prefer them to be equal.

Case sensitive meaning

Case sensitivity means setting apart lower case from upper case letters in a program, software, or computer system. Some other terms with a similar meaning are case-preserving or case-specific. Case sensitivity means words that sound or appear identical, but they use different letter cases; thus, not considered equal. That explains why case sensitivity started as a distinguishing method of types or words to indicate the beginning of sentences or designating someone’s Name. 

Case sensitivity in computer programs 

A case-sensitive program can distinguish and recognize different cases in a file name and queries. However, they may not return the correct file or perform the intended function without the proper letter case. This means that case-sensitive systems can refuse to pill up a file titled English_1003_Syllabus if you type “syllabus.”

This is different from case blindness/case-insensitivity cases, which don’t distinguish between upper and lower case. Case insensitive applications don’t notice letter cases and will usually function regardless of whether a user enters. The best example here is email, which works regardless of the type the case type you use. However, email password is case sensitive. 

Case sensitivity comes with many benefits, including:

  • Flexibility – programmers can choose to use upper, lower, or mixed cases in their programs. Earlier programs were exclusively for lower case, which is easier to type. 
  • Makes parsing easier – you can force particular identifies, to begin with, upper or lower case; in turn, that produces a clean syntax. 
  • Allows many convenient coding conventions resulting in cleaner and easier to understand codes 

Case Sensitive/Insensitive Technology 

Databases, software, programs, and most other technologies have a different response to different letter cases. Commands, file names, usernames, passwords, and programming language tags are often but not always case sensitive. 

Advance to the next level in your career.  Click this affiliate link to register for the Data Science Masters Program.

In programming languages, case sensitivity offers variety, as earlier stated. But the resulting program can very difficult to handle. Different things can be easily confusing, making the entire process challenging. 

  1. The use of keywords and case sensitivity: how many keyword elements in your program do you want to be case sensitive? Declaration of terminologies varies. For instance, you can tailor the program to accept the aspect ‘int’ in various ways – ‘INT,’ ‘iNT,’ ‘Int’ or ‘inT.’ Or, it can accept all of them as the same word. 
  2. The case sensitivity of user-defined elements of languages like functions, variables, and structs. How you design the Haskell compiler to decides what happens with different functions matters. For instance, what happens with int B and int b? 
  3. Run time programs – you can create run time programs to be case sensitive or case insensitive. So, the system can decide how to print different aspects – for instance, Mrs. Janet or MRS. JANET. 

Databases and case sensitivity have a complex relationship. Some databases have software that can automatically read a set case – this makes queries challenging. Coders can reset the software manually to ignore cases, allowing users to make queries easily. Identifies are often case sensitive in some databases, e.g., items, within columns and tables. 

What is case sensitive example?

There is a lot of examples that can help to understand the meaning of case sensitivity. A computer can treat upper case letters distinct from each other (case-sensitive) or similar (case-insensitivity). For instance, if you search for a book titled “Cow,” both Cow and cow are significant to the searcher. In this case, they perform a case insensitive search. 

Google treats search queries as case-insensitive – it interprets the requests in lowercase. So, whether you type cow, Cow, or COW, the google search engine will return the same result. 

However, some searches are strictly case sensitive – for instance, some searches in the online encyclopedia. In this case, it’s crucial to use letters as required – either upper or lower case. 

If a similar word has the same letter meaning different meanings, other cases are essential. For example, RAM, i.e., stands for Random Access Memory, a computer part, and Ram, a Hindu deity, can make it difficult for a search engine to differentiate and interpret the terms correctly due to the absence of case sensitivity.

Ideally, case sensitivity differs with the situation.

  • Searching: most search systems aren’t case sensitive, but that depends on the nature of the operation. Most searchers want to get results based on the input, especially when searching for trademarks or human names. For example, a search for ‘Jade’ should return ‘Jade’ and not ‘jade.’ If you search for Friendly fire on Wikipedia, you get a military article. However, if you search Friendly Fire, it returns the disambiguation page.
  • Passwords: passwords usually are treated as case-sensitive by authentication systems. This lets users increase the complexity of passwords. 
  • Usernames: to facilitate memorization, eliminate mistake and fraud possibility and reduce typing complexities, authentication systems treat user names as case sensitive. Sometimes, two users can be identical in every aspect. But the systems aren’t case blind. 
  • File names: Microsoft office OS is case insensitive, while Unix-like OS is case sensitive on the aspect of file names. However, most file systems are case-sensitive. 
  • URLs: for the path, fragment, query, and authority portion of a URL, it may or may not be case sensitive. Typically, it depends on the receiving web server. However, the host and scheme parts are strictly lower case. 
  • Variable names: this varies with the programming language type – some are case sensitive while others are not. C++, C, and Java have identified case-sensitive cases, while Ada and ABAP are case insensitive. 

Which language is case sensitive?

Currently, almost all languages are case-sensitive. Loo, while writing a source code, some languages expect that some words are either lower case or upper case. If you register them otherwise, there will be a problem. So you have to write them as it demands; else, the compiler or interpreter won’t understand that specific word resulting in an error. 

Take a look at these two codes:

Code A.

document.write(‘Hello, world!’);

Code B

document.Write(‘Hello, world!’);

These are JavaScript codes, and they look pretty much similar. But the second code is not correct because the word Write begins in uppercase. 

Case-sensitive programming languages include C++, Java, C#, Verilog, JavaScript Ruby, Python, and Swift. These languages are case-sensitive for their identifiers. 

Programming languages that do not care how developers write the source code are case insensitive. Developers can use all lower case, all upper case, or capitalize only the first letter and not the outcome. Such languages include Pascal, Basic, and SQL. 

Program identifier

A program identifier is simply a name that a user assigns to program elements like the template, variable, type, function, namespace, or function. Typically, it is limited to digits, underscores, and letters. Words like ‘int,’ ‘new,’ and ‘break’ are reserved keywords. As such, they cant be used as identifiers. In basic terms, identifiers are used to identify the elements of a program in the code. 

In Haskell, an identifier features a letter followed by zero or more digits, letters, underscores, and single quotes, just as in other languages. There is a lexical distinguish in two namespaces:

  • Those beginning with lower case letter, i.e., the variable identifier 
  • Those starting with an upper case letter – construct identifier 

Identifiers are case-preserving. The three distinct identifiers are Name, naMe, and Name. The first two terms represent variable identifiers, while the last is the constructor identifier. 

Haskell treats underscore (_) as a lowercase letter and occurs where a lower case letter occurs. However, by itself, “_” is a reserved identifier and is used as a wild card in patterns. 

Recognizing the Difference

Different languages represent the same word differently. For instance, the term ‘true’ in python is in the capital, while Swift is all in lower case. 

Python :

if currentScore > highScore :

    return True

else :

    return False


if currentScore > highScore {

    return true

} else {

    return false


However, some words are similar across all programming languages. If you are just getting started in programming, it might not sound apparent; keep on learning, and you’ll be able to notice and remember the difference. The programmer text editor can offer the best help – they easily identify when you are writing the wrong syntax. 

Haskell data case insensitive

Haskell is known to be case-sensitive particularly when dealing with identifiers. But a deep understanding of Haskell data structures can help developers deal with the case insensitive part of the data structure in Haskell. 

Mainly, developers deal with unordered data but indexed by a key. Unix users must list user IDs as well as the textual usernames corresponding to them. The exact value lies in the ability to look up a textual username for a given user ID but not the order of the data – that implies that the user ID is the key to the database. 

If Data Analytics is your thing – click this affiliate link to registers for the Data Analytics Masters Program.

Haskell offers various ways to handle data structured in this manner. The standard basic methods are map types supplied by the and association lists. The association lists are simple, making them more convenient. Typically, they are standard lists in Haskell – here, all normal list functions work with association lists. If you have large data sets, Map offers the best edge over the association list.

While Haskell remains case sensitive, developers can employ a module to perform data insensitive acts – Data.CaseInsensitive.

During documentation, the use of continuous integration (CI) is needed. This coding philosophy sets practices that drive developers to implement small changes in a code. Besides, it allows checking code and version control repository as required. Modern applications need developing code in various tools and platforms; so, having a mechanism that integrates and validates its changes is excellent. 

CI’s technical goal is to is establishing an automated and consistent way of building, packaging, and testing applications. Code changes can be done more frequently within the integration process, leading to better collaboration and better software quality. 

data CI Source#

A CI offers case insensitive comparison for string-like types –Text, Strings, and ByteStrings. A CI structure features an instance for the IsString, which alongside the OverloadedStrings language extension, lets developers write case insensitive string literals such as 

> (“Content-Type” :: CI Text) == (“CONTENT-TYPE” :: CI Text)


Data.String features string type and associated operations. A string is merely a list of characters. In Haskell, string constants are value string types. By contrast, the class IsString a where the overloaded string extension uses a class for string-like data structures. 

Now performing case insensitive codes in Haskell requires using a module that supports each of the operations. That will mean have a clear understanding of the methods and data. Besides, strings play a critical role. So, developers need to understand methods on lines, functions on the string, and map effectively.   

Are variable names case sensitive?

A variable is a reference to information or a symbolic name. The Name of the variable represents the information that the variable contains. Why are they called variables? The reason is that the designated information is liable to changes, but the variables’ operations remain the same. 

Generally, programs are written with symbolic notation, making the statement to be true symbolically – for instance, the average of two values can be arrived at by average = (grade_1 + grade_2) / 2.0. the average of the variable contains the average grade regardless of the scores stored in the two variables – grade_1 and grade_2.

A variable name is, thus, any mixture of lower and uppercase characters. The case is usually preserved for display purposes. The storage and display of variable names should be precisely specified on the commands that read data or create new variables. Examples given: Compute NewVar = 1 creates a new variable, displayed as NewVar in your Data Editor and output from any procedures, showing variable names.

Commands referring to existing variable names aren’t case-sensitive. For instance:


All these functionalities are equivalent. However, in some languages like Japanese, some characters exist in both wide and narrow forms. In this case, they are considered different and are displayed in the form they are entered. 

Sometimes long variable names many require to wrap onto many lines in the output. In this case, attempts are made to break lines at periods, underscores, and lower to upper case changes.

At times, you can use RENAME VARIABLES command to change the case of any characters in a variable name.

RENAME VARIABLES (newvariable = NewVariable).

The case is usually ignored for the existing variable name specification – any type of lower and upper case combination works. And in the case of the new variable Name, case preservation occurs as entered for display purpose. 

Variable actions

A variable allows to do a few things: 

  • Creating a variable: you can create a variable and name it – naming allows developers to represent all possible values within it. For example – data_points, midterm_score, midterm_scores, course_name, etc.
  • Insert information in that variable – this new information destroys what was there before. 
  • ‘Place’ information into a variable using assignment operator such as midterm_score = 93
  • Copy the information by writing the Name of the variable. The computer completes the action as in the case of average – for instance, average = (grade_1 + grade_2) / 2.

Are identifiers case sensitive?

The underlying operating system determines whether or not an identifier is case-sensitive. Windows-based operating systems aren’t case sensitive, while Unix-based systems are case sensitive. On the other hand, Mac OS X is usually not case sensitive but can be in case UFS volumes are used.

System case sensitivity may affect tables, databases, table aliases, and trigger names. However, column aliases, columns, index, event names, and stored routine aren’t case sensitive. 

There is no specified limit to the maximum identifier length, and an identifier includes a letter, digits, and special characters. However, an identifier may not start with a digit as well as must not have any spaces. 

Tibbo BASIC compiler is case insensitive, where abc, ABC, and Abc refer to the same identifier. This is the BASIC tradition. On the other hand, the Tibbo C compiler is case-sensitive. Therefore ABC, abc, and Abc make up three different identifiers. These fully correspond to the ANSI C standard.

The Linker is case insensitive, as it sees everything in lowercase. That means that abc, ABC, and Abc is just the same identifier.

For both Tibbo BASIC and Tibbo C, the parser is case-preserving. Additionally, in BASIC files, the parser is much more case-preserving as it views ABC and abc as two separate entities. Practically, case sensitivity in C is unique due to the case insensitivity of Linker. You can therefore deduce the following:

Developers can define local variables X and y in the same local scope without any challenges. 

Developers can’t define functions FUNC() and func() or global variables Y and y. the impossible is due to the Linker. 

Also, the log file group names are sensitive to letter cases, and the server system of the lower_case_table_names variable plays a key role. Essentially, it determines whether the comparison of aliases table names and database names is case-sensitive. 

If set to zero, Unix-based systems default, the comparison of the table names, aliases, and database names are case-sensitive. On the other hand, if set to 1, which is default to windows, the names are stored in lower case, and the comparison is not in a case-sensitive manner.  

When set at 2 (default for Mac OS X), the names are compared in lower case but stored as declared. 

With these revelations, developers can finetune a Unix-based system to behave like Windows and ignore case sensitivity. However, it is impossible to make a windows system behave like a Unix-based system. The reason is underlying Windows filesystem doesn’t support this.

Luis Gillman
Luis Gillman

Hi, I Am Luis Gillman CA (SA), ACMA
I am a Chartered Accountant (SA) and CIMA (SA) and author of Due Diligence: A strategic and Financial Approach.

The book was published by Lexis Nexis on 2001. In 2010, I wrote the second edition. Much of this website is derived from these two books.

In addition I have published an article entitled the Link Between Due Diligence and Valautions.

Disclaimer: Whilst every effort has been made to ensure that the information published on this website is accurate, the author and owners of this website take no responsibility  for any loss or damage suffered as a result of relience upon the information contained therein.  Furthermore the bulk of the information is derived from information in 2018 and use therefore is at your on risk. In addition you should consult professional advice if required.