1 files changed, 113 insertions, 0 deletions
diff --git a/proc.c b/proc.c
new file mode 100644
index 0000000..ff1197f
--- /dev/null
+++ b/proc.c
@@ -0,0 +1,113 @@
+#include <string.h>
+#include "proc.h"
+
+/* procedures */
+
+void proc_init(Proc *proc, Str name) {
+	memset(proc, 0, sizeof(Proc));
+	Graph *g = &proc->graph;
+	proc->pool.arena = &proc->perm;
+	proc->scope.arena = &proc->perm;
+	g->pool = &proc->pool;
+	g->start = node_new(g, N_START, NULL);
+	g->start->type = (Type) {
+		.lvl = T_BOT,
+		.t = T_TUPLE,
+		.next = NULL
+	};
+	g->stop = node_new_empty(g, N_STOP);
+	g->ctrl = g->start;
+	g->keepalive = node_new(g, N_KEEPALIVE, NULL);
+	proc->name = name;
+}
+
+void proc_free(Proc *proc) {
+	arena_free(&proc->perm);
+	arena_free(&proc->scratch);
+}
+
+/* scope */
+
+NameBinding *scope_find(Scope *scope, Str name) {
+	for (ScopeFrame *f = scope->tail; f; f = f->prev) {
+		for (NameBinding *b = f->latest; b; b = b->prev) {
+			if (str_eql(b->name, name)) {
+				return b;
+			}
+		}
+	}
+	return NULL;
+}
+
+ScopeFrame *scope_push(Scope *scope) {
+	ScopeFrame *f;
+	if (scope->free_scope) {
+		f = scope->free_scope;
+		*f = (ScopeFrame) { 0 };
+		scope->free_scope = f->prev;
+	} else {
+		f = new(scope->arena, ScopeFrame);
+	}
+	f->prev = scope->tail;
+	scope->tail = f;
+	return f;
+}
+
+ScopeFrame *scope_pop(Scope *scope, Graph *g) {
+	ScopeFrame *f = scope->tail;
+	scope->tail = f->prev;
+	f->prev = scope->free_scope;
+	scope->free_scope = f;
+	for (NameBinding *b = f->latest; b; ) {
+		NameBinding *p = b->prev;
+		b->prev = scope->free_bind;
+		scope->free_bind = b;
+		node_remove(g, b->node, g->keepalive);
+		b = p;
+	}
+	return scope->tail;
+}
+
+/* returns previous value */
+NameBinding *scope_bind(Scope *scope, Str name, Node *value, LexSpan pos, Graph *g) {
+	NameBinding *prev = scope_find(scope, name);
+	NameBinding *b;
+	if (scope->free_bind) {
+		b = scope->free_bind;
+		*b = (NameBinding) { 0 };
+		scope->free_bind = b->prev;
+	} else {
+		b = new(scope->arena, NameBinding);
+	}
+	b->name = name;
+	b->prev = scope->tail->latest;
+	scope->tail->latest = b;
+	b->node = value;
+	b->src_pos = pos;
+	node_add(g, value, g->keepalive);
+	return prev;
+}
+
+NameBinding *scope_update(NameBinding *b, Node *to, Graph *g) {
+	Node *n = b->node;
+	node_add(g, to, g->keepalive);
+	b->node = to;
+	node_remove(g, n, g->keepalive);
+	return b;
+}
+
+/* adds to keepalive so these aren't invalidated */
+void scope_collect(Scope *scope, Graph *g, ScopeNameList *nl, Arena *arena) {
+	for (ScopeFrame *f = scope->tail; f; f = f->prev) {
+		for (NameBinding *b = f->latest; b; b = b->prev) {
+			node_add(g, b->node, g->keepalive);
+			ZDA_PUSH(arena, nl, (ScopeName) { b->name, b->node });
+		}
+	}
+}
+
+void scope_uncollect(Scope *scope, Graph *g, ScopeNameList *nl) {
+	for (int i = 0; i < nl->len; i++) {
+		node_remove(g, nl->data[i].node, g->keepalive);
+	}
+}