This documentation is for: ctocpp, version 0.1
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These scripts allow to convert a C file or a whole C project to C++.
I have written it because I have not found a such tool over the Net.
These are simple scripts, anyway. To work, they require the C source
written with a good programming style: one statement per line is
required in most case.
Programs are available over the web to format properly C sources.
Before to start, you need to mark as "static", any variable or function
you want not to be included as class members.
The scripts build classes, and global variables will become members of
the classes, functions will become methods.
Being an all static system at this stage, the new program is not very
different of the C one, apart to be more readable.
But this is a basis to add new classes and methods or to integrate it
in a larger C++ project.
For Windows, Linux and others, as Python is universal.
Requires the python language (www.python.org) installed.
To convert your C project into a C++ one, you need for:
- Some files with ".c" extensions.
- The python interpreter installed. (Get it at www.python.org)
- The files below, from the current archive:
wstring.py pattern.py mklist.py lexer.py mover.py
mkclass.py allhead.py iscomp.py mkcpp.py mkheader.py
Under Windows only:
ctocpp.bat mkclass.bat mkcpp.bat
allhead.bat mover.bat mklist.bat mkheader.bat
Under Unix only:*
ctocpp mkclass mover mkheader mklist allhead mkcpp
Conventions:
- C sources must have the .c extension.
- C headers must have the .h extension.
- a variable with the "static" modifier remain global and doesn't
become a class member (nothing to do with a C++ static member!
class attributes are declared as static from variable not
declared as static, because static for C++ class is a different
thing).
Conversion requires several passes:
1) Use mkheader.py to produces correct header files.
2) Use mkclass.py to create the C++ classes.
The name of a class is the name of the C file,
all variables and functions will be declared static.
You can change manually the class produced into ".hpp" files.
3) Use mkmethod.py to produce ".cpp" files inside which
all c functions are transformed into methods according to
the class declaration.
Global variables are removed from the .cpp files.
4) Use mkcpp.py to transform any C references of variables and
functions to C++ equivalents references to attributes and
methods, according to the classes declarations.
You need also a makefile to build your C++ program. This
depends the compiler you use and is not covered here.
A sample batch is included that works with bcc 5.5 and a shell script
that use GCC.
These tools may be used for a more general purpose:
- makehead.py
may also be used as a standalone tool to make and update
c header files.
- search.py
is a general purpose search-replace tool to process strings
or identifiers inside text files.
- mover.py
translates a project from a directory to another one. Changes
#include statements.
- some .py files not named above are modules called by the named
scripts.
- The program assumes the C code is written with a good
programming style. What is hard to read for an human will
be hard to parse for the program too.
- Define statements used in code must be moved to header
file, they are processed only in some cases by the scripts.
- The step 3 and 4 are the more complex ones. If the conversion
doesn't work, then perform them manually instead, they are also
the less fastidious ones. The other ones should work without
problem, and luckily, what they do is also the more annoying part!
- If your project uses a list of files as the ones of Turbo C,
you don't need for mklist.
Mklist is able to build this list providing that all functions
have a prototyp in header file and this header file is included
in each source using the function. Otherwise you have to complete
the list.
- The #include statements should use the "" enclosures for your
header files and the <> ones, for external libraries.
For example: #include <stdlib.h>
#include "myheader.h"
- The script doesn't manage conditional compilation.
Statements as #if or #ifdef are not managed when building
the header file.
- Functions may take macro arguments as the FILE one.
This can be a problem inside an header file. Such problem is
already solved if each function has a prototype in the original
source, but this is no always the case, as old compiler allows
to omit them.
When such problems are encoutered in producing the header file,
change manually the file.
- The name automatically choosen, that of the file, may conflict.
A function with the same name that the file will has same name
that a class and will be considered as a constructor.
If your source are are saved and if you are sure your code is
compatible with C++ conventions that are more restrictive than
C ones, but compatible with it, you can type a single command:
COMMAND: ctocpp mainfile.c projectlist
In other cases, process step by step as below...
Step 1: Move the files. This is optional.
COMMAND: mover mainfile.c olddir@newdir [olddir@newdir]
- mainfile.c is the file that holds the main() function.
- olddir is a directories where the files are stored.
- newdir is the new location.
- several old@new couples are required if the project stays
inside several directories.
You can move all directories into a single one.
N.B.: If you move the files with a file manager, the #include
statements will not be updated.
Step 2: Make the project list with mklist.py
COMMAND: mklist mainfile.c prjlist
- mainfile.c is the file that holds the main() function.
- prjlist is the name of the file that will contains the list of
all .c sources of the project (you choose a name for it).
It will be overwritten without prompting.
Step 3: Make declarations inside headers, matching the
definitions inside sources.
C compiler are less restrictive than C++ one, a function
can be used without prototypes.
To update your sources to C++ rules, use mkheader.py
COMMAND: mkheader @prjlist
- do not forget the @ before the project's filename.
Step 4:
If you want to define you own classes, skip this step.
mkclass allows to make a class from variables and prototypes
from an header file. If produces a new .hpp file and doesn't
change the previous header.
COMMAND: mkclass @prjlist
- Do not forget the symbol before the project's filename.
- If a function has name that is that of the file, it will
be considered as a constructor. The class name must be changed.
When all C++ headers are created you may change the default
classes names or move their members from class to class if
you want.
If a method has the same name that the class, you must to
rename the class, as the name is reserved to a constructor.
Step 5:
Now you need the list of all header files.
This is not the same that the list of sources, as the project
may use header to include with no corresponding source.
COMMAND: allhead mainfile.c headlist
- Headlist if the name of the file to create, that will hold
all header filenames. No symbol at this stage (It is used
to differentiate a source from a list of files).
- The file is overwritten without prompting.
Step 6:
The last step produces a full set of C++ files with .cpp
extensions, from .c and .hpp files.
- Function are transformed in methods.
- Global variables are made static and integrated into class declarations.
- Call of functions are replaced by call of methods.
- Global variables references are replaced by references to members.
COMMAND: mkcpp @prjlist @headlist
- Prjlist is the name of the file that hold all .c sources
in the project. The symbol prefixes the name.
- Headlist is a file that holds all .h headers. Symbol before it.
Now you are ready to compile your C++ project.
N.B.: If you omit the "@" symbol in front of a filename
when required, the script will process the file itself,
not a list of files. This allows to convert a single file.
Example: CDList
The / symbol is inverted for Windows.
The scripts are installed into the /ctocpp directory.
The CDList files are in the /cdwin directory.
The program use a personal GUI library, in the /gui directory.
The main function is inside the listit.c file.
I choose to move all necessary file into the /cdnew directory
and give the new project file the "cdlist" name:
A single script, "ctocpp.bat" performs the steps 2 to 6:
You can type simply: ctocpp \cdnew\listit.c \cdnew\cdlist
But this is not recommend, as you may have to rename classes
automatically created.
Or you can perform detailed steps:
From the /ctocpp directory:
Step 1: mover /cdwin/listit.c /gui:/cdnew /cdwin:/cdnew
Step 2: mklist /cdnew/listit.c /cdnew/cdlist.prj
Step 3: mkheader @/cdnew/cdlist.prj
Step 4: mkclass @/cdnew/cdlist.prj
Step 5: allhead /cdnew/listit.c /cdnew/cdlist.hpj
Step 6: mkcpp @/cdnew/cdlist.prj @/cdnew/cdlist.hpj
N.B.:
- the @ symbol is used when the file is a list of files and
when it is read, not when it is created.
- under Windows, python xxx.py may be replaced by xxx.bat
The new C++ project may be compiled with the cdcpp.mak
makefile for Turbo C++ 3.1 in the cdwin directory.
Delete the .c files and type: make -fcdcpp.mak