Computer systems use binary language. All the inputs given in other complex languages are analyzed using compilers or interpreters and then translated into the language of the system. Hence, the instructions are executed. The machine code is generated using these. But both works differently. An interpreter is memory efficient but time-consuming. While compilers are swift enough but need linking and higher memory.
Compilers vs Interpreters
The main difference between compiler and interpreter is that a compiler analyses the source code entirely and translates it, but an interpreter goes through a single line at a time to translate. Both compiler and interpreters are used to execute the instructions in a programming language. The source code or the input provided to systems is usually in a high-level language that cannot be recognized by the computer. Interpreters are preferred by beginners as they tend to make mistakes more. The error spotting in interpreters makes it handy. But it is time-consuming. So advanced programmers will not benefit from this feature.
Compilers read the source code wholly at once and translate it into the machine language. C, C++, and C# are examples of such. The errors in the source code will be highlighted once after the compiler analyses it. Grace Hopper gave it the name compiler. They are large programs with many abilities. Compiled programs are efficient. It also protects the source code and related programs.
Interpreters analyze a line at a time and change it into machine language. If an error is found, the interpreter halts the process and restarts only when it is removed. Therefore, removing bugs is simple. There is no requirement for object code generation. Python, MATLAB, Ruby, and Perl are examples of interpreters.
Comparison Table Between Compilers and Interpreters
| Parameters of Comparison | Compilers | Interpreters |
| Functioning | The whole source code is translated into machine language and then executed. | Each line is translated and finally executed. |
| Time | Less time to execute | Requires more time |
| Error detection | Only after the whole source code is analyzed | Stops when an error is detected and resumes when it is corrected |
| Generation of object code | Present | Absent |
| Examples | C, C++, C# | Ruby, Python, Perl |
What are Compilers?
A compiler translates the high-level language into the language of the processing unit. The system uses object code. Therefore, all the inputs must be translated into their language. This is where a compiler comes into action. It converts the received source code to the computer’s programming language. A computer uses binary language to operate. So the instructions should be in the same language.
The process is known as compilation. It has multiple steps. Starting from analysis where the compiler understands the source code to convert it and acting is a rapid process. In analysis, there are three sub-steps: initially, the collective meaning is formed using linear analysis. Secondly, the hierarchical analysis to divides the collective meaning groups called tokens, and finally, the semantic analysis assures that the source code has a meaning.
There is a structure for the compilation process. The lexical analyzer step involves the source code and scans it thoroughly to find the mistakes. Then the syntax analyzer uses the input received from the lexical analyzer to check the grammar. Its input is taken by the semantic analyzer that checks the validity of the code. In the next phase, intermediate code is generated, which is optimized by a code optimizer. Thus, the target code is generated.
Three types of compilers are there. This classification is based on a broader sense. Single-pass compilers translate the source code into machine code directly. A two-pass compiler has two sections called the front end and back end. The final type is a multi-pass compiler that processes the input language multiple times. Cross compilers, threaded code compiler, just-in-time compiler, load and go compiler, and incremental compiler are some other types of compilers.
What are Interpreters?
Interpreters change the source code into a comprehensible language by going through one statement at a time. It does not generate the object code. The intermediate form generated by the interpreter is directly executed. It helps programmers to analyze each line without much time. The source code is not changed into an object code which makes interpreters resourceful.
The interpreter uses certain strategies to perform its functions. It may syntactically analyze the input language like the Lisp programming language or translate it to an intermediate representation as Python or carry out the instruction derived from the precompiled code in the system like UCSD Pascal. Either of the three strategies is used.
The programs are inserted before, and the interpreter is linked to execute the functions. Some systems combine two strategies to perform functions like Java. Interpreting systems can do translation jobs similar to compilers. There are different types of interpreters. Bytecode interpreters that convert source code into bytecode and execute it. Threaded code interpreters make use of pointers. Self-interpreters interpret themselves. Abstract syntax tree interpreters change the source code to AST and execute.
Main Differences Between Compilers and Interpreters
- Compilers are less time-consuming than interpreters.
- Compilers generate object code. It is absent in interpreters.
- Information regarding errors is given at last the analysis in compilers. Whereas in interpreters, if an error is found, it stops the process. Thus, it is easier to detect errors in interpreters than compilers.
- Source code is required for later execution in compilers. Interpreters do not require that.
- Compilers translate the whole source code at once, but interpreters take a line at a time for translation.
Conclusion
Both compilers and interpreters have their benefits and perils. Compilers take less time to execute a program, but it is advanced. Changes can be brought into source code only after the complete analysis of the program in compilers. This makes error detection and correction strenuous. Although interpreters need too much time, error correction is easier. Even beginners can use it. Dynamic typing is applicable for interpreted language. It is highly beneficial for programming and development. Compilers can perform well in the production environment.
References
- https://books.google.com/books?hl=en&lr=&id=obI0AAAAQBAJ&oi=fnd&pg=PT4&dq=compiler+&ots=-p9sB7XZzQ&sig=6O7rNokygw1dA9aDxK5wiVsEZAU
- https://dl.acm.org/doi/abs/10.1145/800194.805852