Cfront was the original
compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...
for
C++ (then known as "
C with Classes") from around 1983, which converted C++ to C; developed by
Bjarne Stroustrup
Bjarne Stroustrup (; ; born 30 December 1950) is a Danish computer scientist, most notable for the invention and development of the C++ programming language. As of July 2022, Stroustrup is a professor of Computer Science at Columbia Universit ...
at AT&T Bell Labs. The
preprocessor
In computer science, a preprocessor (or precompiler) is a program that processes its input data to produce output that is used as input in another program. The output is said to be a preprocessed form of the input data, which is often used by s ...
did not understand all of the
language
Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of ...
and much of the
code was written via
translations
Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...
. Cfront had a complete
parser
Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lati ...
, built
symbol table
In computer science, a symbol table is a data structure used by a language translator such as a compiler or interpreter, where each identifier (or symbols), constants, procedures and functions in a program's source code is associated with inf ...
s, and built a
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
for each
class,
function, etc. Cfront was based on CPre, a C compiler started in 1979.
As Cfront was written in C++, it was a challenge to
bootstrap on a machine without a C++ compiler/translator. Along with the Cfront C++ sources, a special "half-preprocessed" version of the C code resulting from compiling Cfront with itself was also provided. This C code was to be compiled with the native C compiler, and the resulting executable could then be used to compile the Cfront C++ sources.
Most of the porting effort in getting Cfront running on a new machine was related to standard I/O. Cfront's C++ streams were closely tied in with the C library's buffered I/O streams, but there was little interaction with the rest of the C environment. The compiler could be ported to most
System V
Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...
derivatives without many changes, but
BSD
The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Be ...
-based systems usually had many more variations in their C libraries and associated stdio structures.
Cfront defined the language until circa 1990, and many of the more obscure corner cases in C++ were related to its C++-to-C translation approach. A few remnants of Cfront's translation method are still found in today's C++ compilers;
name mangling
In compiler construction, name mangling (also called name decoration) is a technique used to solve various problems caused by the need to resolve unique names for programming entities in many modern programming languages.
It provides a way of e ...
was originated by Cfront, as the relatively primitive
linkers at the time did not support type information in symbols, and some template instantiation models are derived from Cfront's early efforts. C++ (and Cfront) was directly responsible for many improvements in
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
linkers and
object file
An object file is a computer file containing object code, that is, machine code output of an assembler or compiler. The object code is usually relocatable, and not usually directly executable. There are various formats for object files, and the ...
format
Format may refer to:
Printing and visual media
* Text formatting, the typesetting of text elements
* Paper formats, or paper size standards
* Newspaper format, the size of the paper page
Computing
* File format, particular way that informati ...
s, as it was the first widely used language which required link-time type checking,
weak symbols, and other similar features.
Cfront 4.0 was abandoned in 1993 after a failed attempt to add
exception support.
Scott Meyers
Scott Douglas Meyers (born April 9, 1959) is an American author and software consultant, specializing in the C++ computer programming language. He is known for his ''Effective C++'' book series. During his career, he was a frequent speaker at co ...
The Most Important C++ Software...Ever
2006 The C++ language had grown beyond its capabilities; however a compiler with similar approach became available later, namely
Comeau C/C++.
References
;Notes
*
*
*
External links
Cfront Releasesa
C++ Historical Sources Archive
C++ compilers
Unix programming tools
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