From 6a3d3e78e063096d4ad17e217bac3ad33fbfa81a Mon Sep 17 00:00:00 2001
From: Jeremiah Orians <jeremiah@pdp10.guru>
Date: Thu, 24 Dec 2020 14:41:14 -0500
Subject: [PATCH] expand the known issues list

---
 known_issues.org | 140 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 123 insertions(+), 17 deletions(-)

diff --git a/known_issues.org b/known_issues.org
index 8d17aa1..6734ee8 100644
--- a/known_issues.org
+++ b/known_issues.org
@@ -1,21 +1,12 @@
 M2-Planet is subset of the C programming language.
 
-Mostly eliminating features that have yet to be proven useful in building compilers, linkers or assemblers.
+Mostly by eliminating features that have yet to be proven useful in building compilers, linkers or assemblers.
 
-* Global variables
-** Assignment
-*** struct initialization
-M2-Planet doesn't support static initialization for structs yet.
-
-Simply because time hasn't been made available for the effort.
-
-Patches for adding support are welcome.
-
-*** AMD64 & AArch64 int initialization wrong
+* AMD64 & AArch64 int initialization wrong
 right now the code in cc_core.c in the function void program() simply doesn't output the correct output for AArch64 or AMD64.
 As the function should numerate the string global_token to determine if the leading 32bits should be 0 or 0xFFFFFFFF and output %0 or %0xFFFFFFFF accordingly.
 
-**** example of failing code
+** example of failing code
 #include<stdlib.h>
 #include<stdio.h>
 #include<string.h>
@@ -44,10 +35,9 @@ int main()
 	return 0;
 }
 
-* Arrays
-** multidimensional arrays return wrong results
+* multidimensional arrays return wrong results
 
-*** example of failing code
+** example of failing code
 #include <stdio.h>
 
 char** env_argv;
@@ -66,20 +56,97 @@ int main(int argc, char** argv)
 
 run with: ./example 12345 abcdef ABCDEF
 
-*** work around code
+** work around code
 char getargchar(int n, int k)
 {
 	char *tmp = env_argv[n];
 	return tmp[k];
 }
 
+* Pointer arithmetic wrong
+It isn't uncommon for complex C programs to iterate over an array using a pointer.
+
+** example of failing code
+#include <stdio.h>
+#include <stdlib.h>
+
+void walk_array(char** array, char** array_end)
+{
+	char** i = array;
+	while(i < array_end)
+	{
+		fputs(i[0], stdout);
+		fputc('\n', stdout);
+		i = i + 1;
+	}
+}
+
+int main()
+{
+	char** array = calloc(10, sizeof(char*));
+	array[0] = "hello";
+	array[1] = "world";
+	array[2] = "how";
+	array[3] = "are";
+	array[4] = "you";
+	array[5] = "today";
+	array[6] = "I";
+	array[7] = "am";
+	array[8] = "doing";
+	array[9] = "fine";
+	walk_array(array, array + 10);
+	return 0;
+}
+
+** work around code
+#include <stdio.h>
+#include <stdlib.h>
+
+// CONSTANT pointer_size sizeof(char*)
+#define pointer_size 1
+
+void walk_array(char** array, char** array_end)
+{
+	char** i = array;
+	while(i < array_end)
+	{
+		fputs(i[0], stdout);
+		fputc('\n', stdout);
+		i = i + pointer_size;
+	}
+}
+
+int main()
+{
+	char** array = calloc(10, sizeof(char*));
+	array[0] = "hello";
+	array[1] = "world";
+	array[2] = "how";
+	array[3] = "are";
+	array[4] = "you";
+	array[5] = "today";
+	array[6] = "I";
+	array[7] = "am";
+	array[8] = "doing";
+	array[9] = "fine";
+	walk_array(array, array + (10 * pointer_size));
+	return 0;
+}
+
+* struct initialization
+M2-Planet doesn't support static initialization for structs yet.
+
+Simply because time hasn't been made available for the effort.
+
+Patches for adding support are welcome.
+
 * typedef doesn't work
 M2-Planet doesn't support this function yet as the time for its development has not been allocated yet.
 
 Patches are welcome
 
 * C style function pointers
-M2-Planet supports universal function pointers FUNCTION
+M2-Planet supports universal function pointer FUNCTION
 Simply delete the typedef and the code works fine in M2-Planet
 
 ** example of failing code
@@ -113,3 +180,42 @@ int main ()
 	fun_make_cell_.name = "bar\n";
 	fun_make_cell_.function();
 }
+
+* logical and do not short circuit
+Both sides of && evaluate because it hasn't been shown to be worth the effort of implementation of short-circuit logic
+
+** example of failing code
+#include <stdlib.h>
+#include <stdio.h>
+
+int boom()
+{
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char* argv)
+{
+	if((0 == argc) && boom())
+	{
+		fputs("impossible code\n", stderr);
+	}
+	return 0;
+}
+
+** work around code
+#include <stdlib.h>
+#include <stdio.h>
+
+int boom()
+{
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char* argv)
+{
+	if(0 == argc)
+	{
+		if(boom())fputs("impossible code\n", stderr);
+	}
+	return 0;
+}