COMPILER

     COMPILER

What Is A Compiler?     

A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or “code” that a computer’s processor uses. Typically, a programmer writes language statements in a language such as pascal or c one line at a time using an editor. The file that is created contains what are called the source statements. The programmer then runs the appropriate language compiler, specifying the name of the file that contains the source statements. When executing (running), the compiler first parses (or analyzes) all of the language statements syntactically one after the other and then, in one or more successive stages or “passes”, builds the output code, making sure that statements that refer to other statements are referred to correctly in the final code.

 How and Why Was First Compiler Compiled?

The A-0 system, written by Grace Hopper in 1951 and 1952 for the UNIVAC I, was the first compiler ever developed for an electronic computer.The A-0 functioned more as a loader or linker than the modern notion of a compiler. A program was specified as a sequence of subroutines and arguments. The subroutines were identified by a numeric code and the arguments to the subroutines were written directly after each subroutine code. The A-0 system converted the specification into machine code that could be fed into the computer a second time to execute the program.The A-0 system was followed by the A-1, A-2, A-3 (released as ARITH-MATIC), AT-3 (released as MATH-MATIC) and B-0 (released as FLOW-MATIC).

The FORTRAN team led by John Backus at IBM is generally credited as having introduced the first complete compiler, in 1957.

Grace Hopper said that she invented it because she was lazy and wished that “the programmer may return to being a mathematician.” She is also well known for her important role in the development of the COBOL programming language (which is still in widespread use for business applications), including the development of the first COBOL compiler.