Added const qualifier to MuCString.

Now MuCString is a (const char*).  It has always been intended
that MuCString instances are not to be modified.  This change just makes
it explicit in the type.

muapiparser.py just ignores the const qualifier.

api.rst

@@ -48,13 +48,16 @@ The Mu Micro VM and Client Contexts
 Mu IDs and names are represented as::
 
     // C-style '\0'-terminated string
-    typedef char *MuCString;
+    typedef const char *MuCString;
 
     // Identifiers and names of Mu
     typedef uint32_t MuID;
     typedef MuCString MuName;
 
-``MuCString`` is the 0-terminated C string type.
+``MuCString`` is the 0-terminated C string type.  A ``MuCString`` points to a
+constant string.  Mu never modifies the string passed into Mu from the client.
+If Mu returns a ``MuCString`` (including aliases such as ``MuName``) to the
+client, the client must not write into the string content.
 
 A Mu instance is represented as a pointer to the struct ``MuVM``::
 

muapi.h

@@ -83,7 +83,7 @@ typedef MuGenRefValue MuIBRefValue;         // irbuilderref
 // Mu IR. If you want to build IR using this C API, use MuCtx->new_ir_builder.
 
 // C-style '\0'-terminated string
-typedef char *MuCString;
+typedef const char *MuCString;
 
 // Identifiers and names of Mu
 typedef uint32_t MuID;

scripts/muapiparser.py

@@ -15,7 +15,7 @@ r_param = re.compile(r'\s*(?P<type>\w+\s*\*?)\s*(?P<name>\w+)')
 
 r_define = re.compile(r'^\s*#define\s+(?P<name>\w+)\s*\(\((?P<type>\w+)\)(?P<value>\w+)\)\s*' + rfrag_commpragma + r'\s*$', re.MULTILINE)
 
-r_typedef = re.compile(r'^\s*typedef\s+(?P<expand_to>\w+\s*\*?)\s*(?P<name>\w+)\s*;', re.MULTILINE)
+r_typedef = re.compile(r'^\s*typedef\s+(?P<const>const\s+)?(?P<expand_to>\w+\s*\*?)\s*(?P<name>\w+)\s*;', re.MULTILINE)
 
 r_struct_start = re.compile(r'^struct\s+(\w+)\s*\{')
 r_struct_end = re.compile(r'^\};')
@@ -141,7 +141,7 @@ def extract_typedefs(text):
     typedefs = {}
     typedefs_order = []
     for m in r_typedef.finditer(text):
-        expand_to, name = m.groups()
+        const_qualifier, expand_to, name = m.groups()
         expand_to = expand_to.replace(" ","")
         typedefs[name] = expand_to
         typedefs_order.append((name, expand_to))