Allocate structs on the heap, not on the stack, in C backend.

TODO.md

@@ -1,23 +1,25 @@
 TODO
 ----
 
-Don't output final value.  Command-line arguments passed to `main`.  (`sysmain`?)
-
-Name mangling for compilers (prepend with `_` most likely.)
+### Tests ###
 
 Tests for unions of unions.
 
 Test for equality of union values.
 
 Tests for multiple occurrences of same type in a union.
 
+Test for casting a union to the same union or a different union.
+
 ### Implementation ###
 
+Name mangling for compilers (prepend with `_` most likely.)
+
 Struct equality in Javascript, stackmac backends.
 
 Figure out a way to do `input`, `read`, and `write` with node.js backend.
 
-Implement `int`, `str`, `chr`, `ord` for Ruby, Javascript, stackmac.
+Implement `int`, `chr`, `ord` for Ruby, Javascript, stackmac.
 
 TaggedValue -> just a tuple.
 
@@ -27,10 +29,17 @@ and void types in unions of (void, X) should only be one value.
 
 AST nodes should have source line numbers, it would be really nice.
 
-C backend.  Other backends (Python? Java? CIL? Scheme?)
+Finish C backend.
+
+Implement garbage collection of some sort in the C backend.  Either that
+or implement some kind of resource-awareness in the language itself.
+
+Other backends (Python? Java? CIL? Scheme?)
 
 ### Design ###
 
+Don't output final value.  Command-line arguments passed to `main`.  (`sysmain`?)
+
 Convenience:
 
 *   Should we have automatic promotion (value tagging?)

src/castile/backends/c.py

@@ -183,6 +183,26 @@ def compile(self, ast):
                 self.compile(child)
             self.indent -= 1
             self.write_indent('};\n\n')
+            self.write_indent('struct %s * make_%s(' % (ast.value, ast.value))
+
+            for child in ast.children[:-1]:
+                assert child.tag == 'FieldDefn'
+                self.write('%s, ' % self.c_decl(child.children[0].type, child.value))
+            child = ast.children[-1]
+            assert child.tag == 'FieldDefn'
+            self.write('%s' % self.c_decl(child.children[0].type, child.value))
+
+            self.write(') {\n')
+            self.indent += 1
+            self.write_indent('struct %s *x = malloc(sizeof(struct %s));\n' % (ast.value, ast.value))
+
+            for child in ast.children:
+                assert child.tag == 'FieldDefn'
+                self.write_indent('x->%s = %s;\n' % (child.value, child.value))
+
+            self.write_indent('return x;\n')
+            self.indent -= 1
+            self.write_indent('}\n')
         elif ast.tag == 'FieldDefn':
             self.write_indent('%s;\n' % self.c_decl(ast.children[0].type, ast.value))
         elif ast.tag == 'FunLit':
@@ -283,7 +303,7 @@ def compile(self, ast):
             self.write(' = ')
             self.compile(ast.children[1])
         elif ast.tag == 'Make':
-            self.write('&(struct %s){ ' % ast.type.name)
+            self.write('make_%s(' % ast.type.name)
             def find_field(name):
                 for field in ast.children[1:]:
                     if field.value == name:
@@ -292,7 +312,7 @@ def find_field(name):
             for field_name in ast.type.defn.field_names_in_order():
                 ordered_fields.append(find_field(field_name))
             self.commas(ordered_fields)
-            self.write(' }')
+            self.write(')')
         elif ast.tag == 'FieldInit':
             self.commas(ast.children)
         elif ast.tag == 'Index':