Programming languages may, however, share the syntax with markup languages if a computational semantics is defined. XSLT, for example, is a Turing complete language entirely using XML syntax. Moreover, LaTeX, which is mostly used for structuring documents, also contains a Turing complete subset. Various visual programming languages have also been developed with the intent to resolve readability concerns by adopting non-traditional approaches to code structure and display. Integrated development environments aim to integrate all such help. The TIOBE Programming Community index is an indicator of the popularity of programming languages. The ratings are based on the number of skilled engineers world-wide, courses and third party vendors.
Other languages are regularly used to write many different kinds of applications. The static semantics defines restrictions on the structure of valid texts that are hard or impossible to express in standard syntactic formalisms.
The practical necessity that a programming language support adequate abstractions is expressed by the abstraction principle. All Turing complete languages can implement the same set of algorithms.
, Wikipedia, Amazon, YouTube and Baidu are used to calculate the ratings. It is important to note that the TIOBE index is not about the best programming language or the language in which most lines of code have been written. For the first time since the start of the TIOBE index nearly 20 years ago, Java and C don’t make up the top 2 positions any more. C is still number one, but it is Python that claims the second position now. Some say that Python’s recent surge in popularity is due to booming fields such as data mining, AI and numerical computing. I believe that Python’s popularity has to do with general demand.
For compiled languages, static semantics essentially include those semantic rules that can be checked at compile time. Examples include checking that every identifier is declared before it is used or that the labels on the arms of a case statement are distinct. Other forms of static analyses like data flow analysis may also be part of static semantics. Newer programming languages like Java and C# have definite assignment analysis, a form of data flow analysis, as part of their static semantics.
For example, PostScript programs are frequently created by another program to control a computer printer or display. More generally, a programming language may describe computation on some, possibly abstract, machine. It is generally accepted that a complete specification for a programming language includes a description, possibly idealized, of a machine or processor for that language. In most practical contexts, a programming language involves a computer; consequently, programming languages are usually defined and studied this way.