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+mission
+-------
+
+minimal C to program the kernel.
+
+design desicions
+----------------
+
+Do we allow structs, functions etc. We could go with global variables
+only and basic types, makes the compiler simpler, but the code maybe
+not so well-structured.
+
+The kind of C dialect we use is a simplified version, so we
+rather write i = i + 1 than i++, ++i
+
+Constructs we need
+------------------
+
+From CPP
+--------
+
+In principle we would like to avoid having to implement CPP
+funtionality, but..
+
+header file includes
+--------------------
+
+#include "filename.h" (but we can go without preprocessor and make it
+a special command in the language itself. We don't want and need
+preprocessor tricks (we think).
+
+include guards
+--------------
+
+#import "a.h" is deprectated in gcc, was Microsoft extension and
+Objective-C.
+
+ok, no go then.
+
+#pragma once in a.h
+
+very simple to implement, avoids clashes of names of guard macros,
+which is very good.
+
+instead of
+
+#ifndef XXXX
+#define XXXX
+#include "a.h"
+#endif
+
+We could implement a simple preprocessor functionality which only
+works with defined symbols (names and no values).
+
+platform switches
+-----------------
+
+#ifdef HOSTED
+#define print(X) puts(X)
+#else
+// our own function print to our kernel
+#endif
+
+alternatives?
+
+Linking to specific implementation files io-host.c vs io-minios.c
+
+debug code
+----------
+
+#ifdef DEBUG
+#endif
+
+constants
+---------
+
+for array dimentions mainly.
+
+#define ACONSTANT 5
+int b[ACONSTANT];
+
+constants can be done with 'enum { ACONSTANT = 5 };'
+
+No this is really a problem when parts of standard C require a macro
+processor just to define things like NULL:
+
+#if !defined(NULL)
+    #define NULL ((void*)0)
+#endif
+
+runtime
+-------
+
+We need a minimalistic runtime (basically the functions needed to write
+the self-compiling first-stage compiler).
+
+crt0 type entry points:
+
+raise
+_start
+_exit
+
+testing
+-------
+
+From the simplest test program on, make sure we generate some output
+and verify it! Even if this means we must write special bootstrap test 
+code..
+
+Make sure we can output all phases of the compiler, lexing/parsing,
+semantics, code generation, etc.
+
+Have a pseudo code generator like "cucu", or maybe better something
+which even runs (Jasmin, Java byte-code), cucu has a Python interpreter
+for the pseudo assembler. The real target we should postpone, as it
+involves linking, ELF, GPT, Intel assembly code and other things which
+complicate issues in the beginning.
+
+Also having a small virtual CPU as in Oberon (where the virtual CPU
+actually can get real :-) ) or as in
+http://schweigi.github.io/assembler-simulator/instruction-set.html
+is an idea.
+The idea is even usable for a running system like
+erlm.github.io/OberonEmulator/
+
+header files
+------------
+
+Generate them, later make the compiler self-aware of source files
+in Oberon-style. For bootstrapping via another C compiler we
+need simple header file (#pragma once only, #include only in the
+C file. For including things which are prerequisites either:
+- the program can define a global series of includes
+- the library or component (like minilib) defines a facade header
+  file
+
+generating header files:
+http://www.hwaci.com/sw/mkhdr/
+
+But, we would like the minic compiler to do this, not yet another
+tool in the chain.
+
+makeheaders plays too many tricks with preprocessors. Another possibility
+is to have a modified C with other constructs which then first gets
+converted into plain C89 with full-preprocessor support.
+
+io.c:
+
+typedef struct Io {
+} Io;
+
+implicit
+-> #include "io.h"
+
+declaration gets moved into io.h
+
+user of a module uses:
+
+import io;