Changes between Version 106 and Version 107 of IR2

Timestamp:

05/20/21 09:10:48 (5 years ago)

Author:

siegel

Comment:

--

IR2

@@ -312 +312 @@
 <T1,T2> struct $pair { T1 left; T2 right; };
 <T1,T2> typedef struct $pair<T1,T2> $pair;
-<T> $system alloc($heap * h, $int n);  // heap allocation of n elements of type T
-$system $free($void * p);  // frees something that was $alloc-ed
+<T> $system T * $alloc($heap * h, T obj);  // add an object to a heap
+$system $free($void * p);  // remove an object from the heap
 $system void $exit();  // terminate process immediately
 $system $bool $terminated($proc p);  // has the process terminated?
@@ -319 +319 @@
 
 }}}
+
+Notes
+
+A heap is an abstraction for a set of objects of possibly different types which can be referenced by pointers.   A C statement that mallocs 10 ints, e.g.,
+{{{
+int * p = malloc(10*sizeof(int));
+}}}
+could be modeled as
+{{{
+$int * p = $undef;
+$int (*p1)[] = $undef; // pointer to array of $int
+p1 = $alloc(&heap, $new_array(10, $int));
+p = ($int*)p1; // equivalently, p = &(*p1)[0];
+}}}
+
+More generally, if the type of objects being malloced is not known, or changes dynamically, one could define a general "object" type...
 
 === bundle.cvh ===