Doc & build process improvement (#5)

* added example to the main Readme

* made a change to avoid duplication of LDFLAGS

Author: aodinokov

README.md

@@ -11,5 +11,54 @@ Reflection implementation is based on [DWARF](https://en.wikipedia.org/wiki/DWAR
 
 **Features**:
 
-* 'Deep' functionality for printing, copying, comparing, and freeing memory of complex data structures: [demo link](/doc/demo/README.md#how-to-demo).
-* Supported on Ubuntu, macOS, Windows (msys2) with gcc or clang
+* Reflection for all native C types.
+* 'Deep' functionality for printing, copying, comparing, and freeing memory of complex data structures.
+* Supported on **Ubuntu, macOS, Windows (msys2)** with **gcc** or **clang**.
+
+[**Example**](/examples/c_app_simplest/):
+
+```c
+#include <stdio.h>  // printf
+#include <stdlib.h> // free
+#include <math.h>   // M_PI, M_E
+#include "metac/reflect.h"
+
+struct test {
+    int y;
+    char c;
+    double pi;
+    double e;
+    short _uninitialized_field;
+};
+
+int main(){
+    // we need to use this construction to wrap variable declaration
+    // to get its type information
+    WITH_METAC_DECLLOC(decl_location,
+        struct test t = {
+            .y = -10,
+            .c = 'a',
+            .pi = M_PI,
+            .e = M_E,
+        };
+    )
+    metac_value_t *p_val = METAC_VALUE_FROM_DECLLOC(decl_location, t);
+
+    char * s;
+    s = metac_entry_cdecl(metac_value_entry(p_val));
+    // next will output "struct test t = "
+    printf("%s = ", s);
+    free(s);
+
+    s = metac_value_string(p_val);
+    // next will output "{.y = -10, .c = 'a', .pi = 3.141593, .e = 2.718282, ._uninitialized_field = 0,};\n"
+    printf("%s;\n", s);
+    free(s);
+
+    metac_value_delete(p_val);
+
+    return 0;
+}
+```
+
+To get more details please refer to the [How to](/doc/demo/README.md#how-to-demo) document.

doc/demo/README.md

@@ -413,6 +413,7 @@ TPL-_meta_demodb=bin_target
 IN-_meta_demodb= \
 	main.meta.o \
 	demodb.meta.o
+LDFLAGS-_meta_demodb=-Lsrc -lmetac
 POST-_meta_demodb=$(METAC_POST_META)
 
 TPL-demodb.reflect.c:=metac_target

doc/demo/step_03/Makefile

@@ -40,6 +40,7 @@ TPL-_meta_demodb=bin_target
 IN-_meta_demodb= \
 	main.meta.o \
 	demodb.meta.o
+LDFLAGS-_meta_demodb=-Lsrc -lmetac
 POST-_meta_demodb=$(METAC_POST_META)
 
 TPL-demodb.reflect.c:=metac_target

doc/demo/step_04/Makefile

@@ -40,6 +40,7 @@ TPL-_meta_demodb=bin_target
 IN-_meta_demodb= \
 	main.meta.o \
 	demodb.meta.o
+LDFLAGS-_meta_demodb=-Lsrc -lmetac
 POST-_meta_demodb=$(METAC_POST_META)
 
 TPL-demodb.reflect.c:=metac_target

doc/demo/step_05/Makefile

@@ -40,6 +40,7 @@ TPL-_meta_demodb=bin_target
 IN-_meta_demodb= \
 	main.meta.o \
 	demodb.meta.o
+LDFLAGS-_meta_demodb=-Lsrc -lmetac
 POST-_meta_demodb=$(METAC_POST_META)
 
 TPL-demodb.reflect.c:=metac_target

examples/c_app_simplest/main.c

@@ -1,6 +1,6 @@
-#include <stdio.h> // printf
+#include <stdio.h>  // printf
 #include <stdlib.h> // free
-#include <math.h> // M_PI, M_E
+#include <math.h>   // M_PI, M_E
 #include "metac/reflect.h"
 
 struct test {

mk/bin.mk

@@ -1,8 +1,8 @@
 # generates target to build binaries and .so
 define bin_target_tpl
 
-# add extra LDFLAGS specific for this target
-$$(addprefix $1/,$2): LDFLAGS+=$$(LDFLAGS-$2)
+# add extra LDFLAGS specific for this target (don't add duplicates)
+$$(addprefix $1/,$2): LDFLAGS=$(filter-out $$(LDFLAGS-$2),$(LDFLAGS)) $$(LDFLAGS-$2)
 
 ifneq ($$(CC-$2),)
 $$(addprefix $1/,$2): CC=$$(CC-$2)

mk/test.mk

@@ -78,7 +78,7 @@ IN-$(2:.checkmk=_checkmk.reflect.c)=$$(dir $(2:.c=))_meta_$$(notdir $(2:.checkmk
 
 TPL-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk)):=bin_target
 IN-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk))=$(2:.checkmk=_checkmk.meta.o)
-LDFLAGS-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk))=$$(LDFLAGS-$(2:.checkmk=))
+LDFLAGS-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk))=$$(LDFLAGS-$(2:.checkmk=_checkmk))
 DEPS-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk))=$$(DEPS-$(2:.checkmk=))
 POST-$$(dir $(2:.checkmk=_checkmk))_meta_$$(notdir $(2:.checkmk=_checkmk))=$$(METAC_POST_META)