oceani: add transparent AddressOf operator for function parameters.

[ocean] / csrc / oceani.mdc

diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index 1ec640f1b4ed6520b17723d36d00d15c1e3a011d..891ce74c2e4d097b0cb9e4143f9dac97c0ec1e77 100644 (file)
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -3327,7 +3327,7 @@ anything in the heap or on the stack.  A reference can be assigned
 ###### Expressions: dereference
 
 ###### Binode types
-       Deref,
+       Deref, AddressOf,
 
 ###### term grammar
 
@@ -3343,6 +3343,9 @@ anything in the heap or on the stack.  A reference can be assigned
                print_exec(b->left, -1, bracket);
                printf("@");
                break;
+       case AddressOf:
+               print_exec(b->left, -1, bracket);
+               break;
 
 ###### propagate binode cases
        case Deref:
@@ -3356,13 +3359,30 @@ anything in the heap or on the stack.  A reference can be assigned
                        return t->reference.referent;
                break;
 
+       case AddressOf:
+               /* left must be lval, we create reference to it */
+               if (!type || type->free != reference_free)
+                       t = propagate_types(b->left, c, perr, type, 0); // UNTESTED
+               else
+                       t = propagate_types(b->left, c, perr,
+                                           type->reference.referent, 0);
+               if (t)
+                       t = find_anon_type(c, &reference_prototype, "@%.*s",
+                                       t->name.len, t->name.txt);
+               return t;
+
 ###### interp binode cases
-       case Deref: {
+       case Deref:
                left = interp_exec(c, b->left, &ltype);
                lrv = left.ref;
                rvtype = ltype->reference.referent;
                break;
-       }
+
+       case AddressOf:
+               rv.ref = linterp_exec(c, b->left, &rvtype);
+               rvtype = find_anon_type(c, &reference_prototype, "@%.*s",
+                                       rvtype->name.len, rvtype->name.txt);
+               break;
 
 
 #### Functions
@@ -3462,6 +3482,14 @@ further detailed when Expression Lists are introduced.
                return 0;
        }
 
+       static struct exec *take_addr(struct exec *e)
+       {
+               struct binode *rv = new(binode);
+               rv->op = AddressOf;
+               rv->left = e;
+               return rv;
+       }
+
        static void function_check_args(struct parse_context *c, enum prop_err *perr,
                                        struct type *require, struct exec *args)
        {
@@ -3473,13 +3501,22 @@ further detailed when Expression Lists are introduced.
 
                while (param) {
                        struct var *pv = cast(var, param->left);
+                       struct type *t = pv->var->type, *t2;
                        if (!arg) {
                                type_err(c, "error: insufficient arguments to function.",
                                         args, NULL, 0, NULL);
                                break;
                        }
                        *perr = 0;
-                       propagate_types(arg->left, c, perr, pv->var->type, 0);
+                       t2 = propagate_types(arg->left, c, perr, t, Rrefok);
+                       if (t->free == reference_free &&
+                           t->reference.referent == t2 &&
+                           !(*perr & Erval)) {
+                               arg->left = take_addr(arg->left);
+                       } else if (!(*perr & Efail) && !type_compat(t2, t, 0)) {
+                               type_err(c, "error: cannot pass rval when reference expected",
+                                        arg->left, NULL, 0, NULL);
+                       }
                        param = cast(binode, param->right);
                        arg = cast(binode, arg->right);
                }