Improve documentation based on latest improvements

doc/mrbgems/README.md

@@ -9,13 +9,14 @@ By default mrbgems is currently deactivated. As long as mrbgems is deactivated
 there is no overhead inside of the mruby interpreter.
 
 To activate you have to make the following changes:
-* set *ENABLE_GEMS* to *true* in *$(MRUBY_ROOT)/Makefile*
-* define *ENABLE_GEMS* in *$(MRUBY_ROOT)/include/mrbconf.h*
+* set ```ENABLE_GEMS``` to ```true``` in *$(MRUBY_ROOT)/Makefile*
+* comment out ```DISABLE_GEMS``` in *$(MRUBY_ROOT)/include/mrbconf.h*
 * activate GEMs in *$(MRUBY_ROOT)/mrbgems/GEMS.active*
 
-Every activated GEM has to be listed with his absolute path in *GEMS.active*. It
-is possible to point to an alternative activate file:
-* set *ACTIVE_GEMS* to your customized GEM list in *$(MRUBY_ROOT)/Makefile*
+Every activated GEM has to be listed in *GEMS.active*. You have to point to
+the GEM directory absolute or relative (based on *mrbgems/g*). It is possible
+to point to an alternative activate file:
+* set ```ACTIVE_GEMS``` to your customized GEM list in *$(MRUBY_ROOT)/Makefile*
 
 ## GEM Structure
 
@@ -23,6 +24,8 @@ The maximal GEM structure looks like this:
 
 ```
 +- GEM_NAME         <- Name of GEM
+   |
+   +- include/      <- Header files for C extension
    |
    +- mrblib/       <- Source for Ruby extension
    |
@@ -37,23 +40,23 @@ The maximal GEM structure looks like this:
 
 The folder *mrblib* contains pure Ruby files to extend mruby. The folder *src*
 contains C files to extend mruby. The folder *test* contains pure Ruby files
-for testing purposes which will be used by *mrbtest*. The *Makefile* contains
-rules to build a *gem.a* file inside of the GEM directory. Which will be used
-for integration into the normal mruby build process. *README.md* is a short 
-description of your GEM.
+for testing purposes which will be used by ```mrbtest```. The *Makefile* contains
+rules to build a *mrb-GEMNAME-gem.a* file inside of the GEM directory. Which
+will be used for integration into the normal mruby build process. *README.md*
+is a short description of your GEM.
 
 ## Build process
 
-mrbgems will call *make* to build and *make clean* to clean your GEM. You
+mrbgems will call ```make``` to build and *make clean* to clean your GEM. You
 have to build a *mrb-GEMNAME-gem.a* file during this build process. How you
 are going to do this is up to you.
 
 To make your build process more easier and more standardized we suggest
 to include *mrbgems/Makefile4gem* which defines some helper rules. In
 case you include this Makefile you have to define specific pre-defined
-rules like *gem-all* for the build process and *gem-clean* for the clean
-process. There are additional helper rules for specific GEM examples 
-below.
+rules like ```gem-all``` for the build process and ```gem-clean``` for
+the clean process. There are additional helper rules for specific GEM
+examples below.
 
 ## C Extension
 
@@ -61,16 +64,16 @@ mruby can be extended with C. It is possible by using the C API to
 integrate C libraries into mruby.
 
 The *Makefile* is used for building a C extension. You should
-define *GEM* (GEM name), *GEM_C_FILES* (all C files) and
-*GEM_OBJECTS* (all Object files). Pay also attention that your
+define ```GEM``` (GEM name), ```GEM_C_FILES``` (all C files) and
+```GEM_OBJECTS``` (all Object files). Pay also attention that your
 *Makefile* has to build the object files. You can use
-*gem-c-files* to build a *mrb-GEMNAME-gem.a* out of your
-Object code and use *gem-clean-c-files* to clean the object files.
+```gem-c-files``` to build a *mrb-GEMNAME-gem.a* out of your
+Object code and use ```gem-clean-c-files``` to clean the object files.
 
 ### Pre-Conditions
 
 mrbgems expects that you have implemented a C method called
-*mrb_YOURGEMNAME_gem_init(mrb_state)*. YOURGEMNAME will be replaced
+```mrb_YOURGEMNAME_gem_init(mrb_state)```. ```YOURGEMNAME``` will be replaced
 by the name of you GEM. The directory name of your GEM is considered also
 as the name! If you call your GEM directory *c_extension_example*, your
 initialisation method could look like this:
@@ -111,15 +114,15 @@ classes or add new ones in this way. Put all Ruby files into the *mrblib*
 folder.
 
 The *Makefile* is used for building a Ruby extension. You should  define
-*GEM* (GEM name) and *GEM_RB_FILES* (all Ruby files). You can use
-*gem-rb-files* to build a *mrb-GEMNAME-gem.a* out of your Ruby code and use
-*gem-clean-rb-files* to clean the generated C files.
+```GEM``` (GEM name) and *GEM_RB_FILES* (all Ruby files). You can use
+```gem-rb-files``` to build a *mrb-GEMNAME-gem.a* out of your Ruby code and use
+```gem-clean-rb-files``` to clean the generated C files.
 
 ### Pre-Conditions
 
-mrbgems will automatically call the *gem-all* make target of your GEM.
+mrbgems will automatically call the ```gem-all``` make target of your GEM.
 
-mrbgems will also use the *gem-clean* make target to clean up your GEM. Implement
+mrbgems will also use the ```gem-clean``` make target to clean up your GEM. Implement
 this target with the necessary rules!
 
 ### Example
@@ -147,11 +150,11 @@ override existing classes or add new ones in this way. Put all Ruby files
 into the *mrblib* folder and all C files into the *src* folder.
 
 The *Makefile* is used for building a C and Ruby extension. You should
-define *GEM* (GEM name), *GEM_C_FILES* (all C files), *GEM_OBJECTS*
-(all Object files) and *GEM_RB_FILES* (all Ruby files). You can use
-*gem-c-and-rb-files* to build a *mrb-GEMNAME-gem.a* out of your Object
-and Ruby code. Use *gem-clean-c-and-rb-files* to clean the generated
-C files. 
+define ```GEM``` (GEM name), ```GEM_C_FILES``` (all C files),
+```GEM_OBJECTS``` (all Object files) and ```GEM_RB_FILES``` (all Ruby
+files). You can use ```gem-c-and-rb-files``` to build a
+*mrb-GEMNAME-gem.a* out of your Object and Ruby code. Use
+```gem-clean-c-and-rb-files``` to clean the generated C files. 
 
 ### Pre-Conditions