The Survey of Programming Language Classification

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ABSTRACT

 

1.INTRODUCTION

    With the increasing of programming language varieties, more and more programmers have to study and make use of several programming languages in the meantime. Different languages's nature is the same. According to several criteria, languages can be devided into several categories respectively. By studying the criteria and methods of classification, programmers could understand the nature of programming language, and master quickly new languages. But some definitions about language classification on the net are ambiguous and even incorrect at present. To distinguish and definitize these related definitions, this paper surveys Wikis and some technical blogs, and determines clearer definitions in terms of dynamism of language, dynamism of type system,  intensity of type system and compilation of language in sequence. In addition, this paper would classify several frequently-used langueges based on the definitions mentioned above. What calls for special attention is that, this paper doesn't seek precise and theoretic definitions or classification. It just provides relatively plain explanations for development practice.

 

2.CLASSIFICATION OF PROGRAMMING LANGUAGES

2.1 Dynamism of Language

    Dynamic Programming Language(DPL) is sometimes also called Dynamic Language unofficially, a class of high-level programming language that execute many common behaviors at runtime that Static Programming Languages might perform during compilation, including extension of the program, by adding new code, by extending objects and definitions, or by modifying the type system, all during program execution. Most dynamic languages are also dynamically typed, but not all are[1].

    Static Programming Language(SPL) is sometimes also called Static Language unofficially, relative to Dynamic Language.

2.2 Dynamism of Type System

    Dynamically Typed Language, sometimes called Dynamic Type-Checking Language(DCL) is a language in which types are discovered at execution time, the opposite of Statically Typed Language[2].

    Statically Typed Language, sometimes called Static Type-Checking Language(SCL), is a language in which types are fixed at compile time. Most Statically Typed Languages enforce this by requiring you to declare all variables with their datatypes before using them[2].

2.3 Intensity of Type System

    Strongly Typed Language(STL) is a language in which types are always enforced. If you have an integer, you can't treat it like a string without explicitly converting it[3].

    Weakly Typed Language(WTL) is a language in which types may be ignored, the opposite of Strongly Typed Language. WTL doesn't mean no variable types, but one variable's type can be seemed alterable in its life cycle, just with no strict type constraints, and without any explicit conversion. Generally speaking, there is no need to distinguish dynamism of type system for WTL.

2.4 Compilation of Language

    A compiled language is a language whose implementations are typically compilers , and not interpreters[4].

    A interpreted language is a language that avoids explicit program compilation. The interpreter executes the program source code directly, as a processor or scripting does[5].

    A combination of both solutions is also increasingly common: a compiler can translate the source code into some intermediate form (often called bytecode), which is then passed to an interpreter which executes it[4].

    A scripting language or script language isn't a traditional programming language, similar to a "dummy programming language". It supports the writing of scripts, programs written for a special runtime environment that can interpret and automate the execution of tasks which could alternatively be executed one-by-one by a human operator. So maybe we could call it a new interpreted language[6].

 

3.DISCUSSIONG OF SEVERAL LANGUAGES

Table 1. Classification of several frequently-used langueges

 STLWTLSCLC/C++(SPL), C#(DPL), Java(DPL)PHP(DPL), Javascript(DPL)DCLObjective-C(SPL)

3.1 C/C++

    C/C++ are SPLs, SCLs. Generally speaking, we call C/C++ STLs, as it have a declared type, and support the use of explicit casts of arithmetic values to other arithmetic types. But C/C++ are sometimes said to be more weakly typed than C#, Java and so on[7], probably based on the fact that C/C++ supports more kinds of implicit conversions, and allows pointer values to be explicitly cast while Java do not[3].

3.2 C#

    C# is a DPL as a result of its reflection mechanism, and generally speaking, a SCL. But C# added a keyword called "var" from version 4.0, so it also looks like a SCL now. C# is also belonged to STL though it allows disabling dynamic type checking by explicitly putting code segments in an "ansafe context".

3.3 Objective-C

    Objective-C is extension of C, so wo just discuss the extended portion. Objective-C is a SPL, and a DCL due to "id" keyword. Objective-Cis also a STL.

3.4 Java

    Java is a DPL as a result of its reflection mechanism like C#, a SCL and a STL.

3.5 Python

    Python is a DPL, a DCL and a STL.

3.6 PHP

    PHP is a DPL. Although PHP is usually called a WTL, but we could get variable's datatype by gettype() function. Maybe it can be seemed as implicit type conversion like C/C++.

3.7 Javascript

    Javascript is DPL, a WTL.

 

4.CONCLUSION

    This paper surveys determines clearer definitions in terms of dynamism of language, dynamism of type system,  intensity of type system, compilation of language and type safety in sequence, and classify several frequently-used langueges based on these definitions. As we see, a practical programming language tending to be compound of several classifications, or classification boundary being too blurred to make a classification, so frequently causes suspicion and dispute.

 

5.REFERENCES

[1]  http://en.wikipedia.org/wiki/Dynamic_programming_language

[2]  http://en.wikipedia.org/wiki/Type_system

[3]   http://en.wikipedia.org/wiki/Strong_and_weak_typing

[4]  http://en.wikipedia.org/wiki/Compiled_language

[5]  http://en.wikipedia.org/wiki/Interpreted_language

[6]  http://en.wikipedia.org/wiki/Scripting_language

[7]  http://bbs.csdn.net/topics/380249796

(This paper comes from http://blog.csdn.net/nerv3x3/article/details/9199259, Author: nerv3x3)