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/* closure.c -- operations on bindings, closures, lambdas, and thunks ($Revision: 1.1.1.1 $) */
#include "es.h"
#include "gc.h"
/*
* Closure garbage collection support
*/
DefineTag(Closure, static);
extern Closure *mkclosure(Tree *tree, Binding *binding) {
gcdisable();
Ref(Closure *, closure, gcnew(Closure));
closure->tree = tree;
closure->binding = binding;
gcenable();
RefReturn(closure);
}
static void *ClosureCopy(void *op) {
void *np = gcnew(Closure);
memcpy(np, op, sizeof (Closure));
return np;
}
static size_t ClosureScan(void *p) {
Closure *closure = p;
closure->tree = forward(closure->tree);
closure->binding = forward(closure->binding);
return sizeof (Closure);
}
/* revtree -- destructively reverse a list stored in a tree */
static Tree *revtree(Tree *tree) {
Tree *prev, *next;
if (tree == NULL)
return NULL;
prev = NULL;
do {
assert(tree->kind == nList);
next = tree->u[1].p;
tree->u[1].p = prev;
prev = tree;
} while ((tree = next) != NULL);
return prev;
}
typedef struct Chain Chain;
struct Chain {
Closure *closure;
Chain *next;
};
static Chain *chain = NULL;
static Binding *extract(Tree *tree, Binding *bindings) {
assert(gcisblocked());
for (; tree != NULL; tree = tree->u[1].p) {
Tree *defn = tree->u[0].p;
assert(tree->kind == nList);
if (defn != NULL) {
List *list = NULL;
Tree *name = defn->u[0].p;
assert(name->kind == nWord || name->kind == nQword);
defn = revtree(defn->u[1].p);
for (; defn != NULL; defn = defn->u[1].p) {
Term *term;
Tree *word = defn->u[0].p;
NodeKind k = word->kind;
assert(defn->kind == nList);
assert(k == nWord || k == nQword || k == nPrim);
if (k == nPrim) {
char *prim = word->u[0].s;
if (streq(prim, "nestedbinding")) {
int i, count;
Chain *cp;
if (
(defn = defn->u[1].p) == NULL
|| defn->u[0].p->kind != nWord
|| (count = (atoi(defn->u[0].p->u[0].s))) < 0
) {
fail("$&parse", "improper use of $&nestedbinding");
NOTREACHED;
}
for (cp = chain, i = 0;; cp = cp->next, i++) {
if (cp == NULL) {
fail("$&parse", "bad count in $&nestedbinding: %d", count);
NOTREACHED;
}
if (i == count)
break;
}
term = mkterm(NULL, cp->closure);
} else {
fail("$&parse", "bad unquoted primitive in %%closure: $&%s", prim);
NOTREACHED;
}
} else
term = mkstr(word->u[0].s);
list = mklist(term, list);
}
bindings = mkbinding(name->u[0].s, list, bindings);
}
}
return bindings;
}
extern Closure *extractbindings(Tree *tree0) {
Chain me;
Tree *volatile tree = tree0;
Binding *volatile bindings = NULL;
gcdisable();
if (tree->kind == nList && tree->u[1].p == NULL)
tree = tree->u[0].p;
me.closure = mkclosure(NULL, NULL);
me.next = chain;
chain = &me;
ExceptionHandler
while (tree->kind == nClosure) {
bindings = extract(tree->u[0].p, bindings);
tree = tree->u[1].p;
if (tree->kind == nList && tree->u[1].p == NULL)
tree = tree->u[0].p;
}
CatchException (e)
chain = chain->next;
throw(e);
EndExceptionHandler
chain = chain->next;
Ref(Closure *, result, me.closure);
result->tree = tree;
result->binding = bindings;
gcenable();
RefReturn(result);
}
/*
* Binding garbage collection support
*/
DefineTag(Binding, static);
extern Binding *mkbinding(char *name, List *defn, Binding *next) {
assert(next == NULL || next->name != NULL);
validatevar(name);
gcdisable();
Ref(Binding *, binding, gcnew(Binding));
binding->name = name;
binding->defn = defn;
binding->next = next;
gcenable();
RefReturn(binding);
}
extern Binding *reversebindings(Binding *binding) {
if (binding == NULL)
return NULL;
else {
Binding *prev, *next;
prev = NULL;
do {
next = binding->next;
binding->next = prev;
prev = binding;
} while ((binding = next) != NULL);
return prev;
}
}
static void *BindingCopy(void *op) {
void *np = gcnew(Binding);
memcpy(np, op, sizeof (Binding));
return np;
}
static size_t BindingScan(void *p) {
Binding *binding = p;
binding->name = forward(binding->name);
binding->defn = forward(binding->defn);
binding->next = forward(binding->next);
return sizeof (Binding);
}
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