Paulo Costa schrieb:
An interesting idea, but probably too hard for a student project, would
be the capability of using a C library without having to manually create
the pas file that translates the c header.
This is what ToPas can already do. But...
That is tedious, error prone
and a mess when the .h changes and we continue to use the wrong .pas and
strange error creep in.
Right, the translator needs exactly the header files as used to create
the library.
I'm aware of possible changes in C libraries and header files, and
that's why now I suggest an Pascal compiler with the added ability to
process C files. Then that compiler would both compile a changed
library, and create an Pascal interface unit at the same time. This is
exactly what the CBuilder does for Delphi.
A transformation of C files into Pascal units, as ToPas can do (to some
degree), IMO is only a provisional solution. When manual intervention is
required in this step, it will be required for every following bugfix or
improvement to the C code.
Also there are a lot of C libraries that are not available to fpc
because nobody had the time to create the bindings. I know that there is
h2pas but it is a off line tool and needs a lot of help from the
programmer.
A better way could be to hack a C compiler (GCC ?) and use only the
parser and the first compilation stage to have the symbols related to
the available functions and structures
This part of ToPas is already finished :-)
and create the pas header from
that information. With such tool we could have almost automatic use of
any c library...
The hardest problem I found in ToPas is an automated handling of the
#defines. They should be classified into literal constants, functions,
macros, and (incomplete) code snippets - where code snippets IMO are of
no use in a Pascal unit. Such classification could be done easily by an
LR parser, but an LL parser only can deal with complete source files.
DoDi
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