1 files changed, 201 insertions, 83 deletions

diff --git a/starts/meaning-vm/helpers.cpp b/starts/meaning-vm/helpers.cpp
index e29962b..da1a974 100644
--- a/starts/meaning-vm/helpers.cpp
+++ b/starts/meaning-vm/helpers.cpp
@@ -4,74 +4,111 @@
 #include "memorystore.hpp"
 
 #include <unordered_map>
+#include <functional>
+
+// sometimes we use an assignment as an expression.
+// is there any reason not to support this?
+// 	well, we would evaluate the assignment when it is converted to a ref
+// 	and currently that is used for something else
+// what is it used for?
+// 	I don't remember ... the assignment is destroyed and unevaluated, so it's likely
+// 	throughout the internal implemntation
+// 		it's used for the comma operator, which doesn't want evaluation.
+// okay, hmm.
+// 	well, if we wanted to support this, we could change the comma operator to not do the
+// 	conversion.  use some other trick.
+// 	[ ] change comma operator to not do conversion: instead take statementcallref object
+// 	[ ] change statementcallref::operator ref() to evaluate and return the statement
+// since we're accumulating more possible bugs, let's think about design.
+// really, ref should be different from syntax sugar.  we should have a special syntax sugar
+// object, and it should not use its own functions at all.  that means not using meaning functions
+// that use them eiher.
+// 	work also brings to light how the product will be made in layers, with each layer using more interdependence and automatic meaning, etc, than the lower one.
+// 	layer0 is raw references and allocations
+//	layer1 is very core meaning
+// 	layer2 is very core syntax sugar
+// 		each layer can only use layers below it.
+
+// concept names are for bootstrapping convenience,
+// to make hardcoding structures easier.
+// hence there is just one single list of them
+std::unordered_map<std::string,concept*,std::hash<std::string>,std::equal_to<std::string>> conceptsByName;
+
+struct name_t : public ref
+{
+	name_t();
+} name;
+
+static ref statement_function("statement-function");
+static ref statement_evaluated("statement-evaluated");
+static ref true_ref("true");
+static ref false_ref("false");
 
 ref operator-(ref a, ref b)
 {
 	return ref(a.name() + "-" + b.name());
 }
 
-statementevaluable ref::operator=(ref that)
+statementcallref ref::operator=(ref that)
 {
 	// for single-line evaluation, we'll need to return a special object
 	declrefs(assign, expression);
 	decllnks(value, to);
-	return {
-		a(assign-expression)[
-			to = *this,
-			value = that
-		],
-		[](ref expr) {
-			declrefs(link, target, unknown, source, type);
-			decllnks(value, to);
-			lnks(link-target, link-type, link-source);
-			decllnks(name, is);
-			ref lhs = expr.get(to);
-			ref rhs = expr.get(value);
-			if (lhs.isa(link) && lhs->get(link-target) == unknown) {
-				// we are a link missing a target: our assignment is making the link happen
-				lhs->unlink(link-target, unknown);
-				lhs->link(link-target, rhs);
-				ref src = lhs->get(link-source);
-				if (lhs->get(link-type) != unknown && src != unknown) {
-					src->link(lhs->get(link-type), rhs);
-					dealloc(lhs);
-					dealloc(expr);
-				} else {
-					throw std::logic_error("not sure what to do with incomplete link assignment");
-				}
-			} else if (rhs->linked(anonymous, true) && !lhs->linked(anonymous, true)) {
-				// this is assignment of anonymous content to empty named concept
-				bool donealready = false;
-				for (auto & l : lhs->links) {
-					if (ref(l.first) == name) { continue; }
-					if (ref(l.first) == is && ref(l.second) == link-type) { continue; }
-					donealready = true;
-				}
-				if (donealready) {
-					// if we have links, and that has links we do not have, an error has been made
-					for (auto & link : rhs->links) {
-						if (ref(link.first) == anonymous) { continue; }
-						if (ref(link.first) == name) { continue; }
-						if (!lhs->linked(ref(link.first), ref(link.second))) {
-							throw std::logic_error(lhs.name() + " already defined otherwise from " + rhs->get(is).name());
-						}
+	statementcallref ret(assign-expression, [](ref expr){
+		declrefs(link, target, unknown, source, type);
+		decllnks(value, to);
+		lnks(link-target, link-type, link-source);
+		decllnks(name, is, anonymous);
+		ref lhs = expr->get(to);
+		ref rhs = expr->get(value);
+		if (lhs.isa(link) && lhs->get(link-target) == unknown) {
+			// we are a link missing a target: our assignment is making the link happen
+			lhs->unlink(link-target, unknown);
+			lhs->link(link-target, rhs);
+			ref src = lhs->get(link-source);
+			if (lhs->get(link-type) != unknown && src != unknown) {
+				src->link(lhs->get(link-type), rhs);
+				expr->unlink(to, lhs);
+				dealloc(lhs);
+			} else {
+				throw std::logic_error("not sure what to do with incomplete link assignment");
+			}
+		} else if (rhs->linked(anonymous, true) && !lhs->linked(anonymous, true)) {
+			// this is assignment of anonymous content to empty named concept
+			bool donealready = false;
+			for (auto & l : lhs->links) {
+				if (ref(l.first) == name) { continue; }
+				if (ref(l.first) == is && ref(l.second) == link-type) { continue; }
+				donealready = true;
+			}
+			if (donealready) {
+				// if we have links, and that has links we do not have, an error has been made
+				for (auto & link : rhs->links) {
+					if (ref(link.first) == anonymous) { continue; }
+					if (ref(link.first) == name) { continue; }
+					if (!lhs->linked(ref(link.first), ref(link.second))) {
+						throw std::logic_error(lhs.name() + " already defined otherwise from " + rhs->get(is).name());
 					}
-					donealready = true;
-				}
-				rhs->unlink(anonymous, true);
-				auto nam = rhs->get(name);
-				rhs->unlink(name, nam);
-				if (!donealready) {
-					ptr->links.insert(rhs->links.begin(), rhs->links.end());
 				}
-				rhs->link(name, nam);
-				dealloc(rhs);
-				dealloc(nam);
-			} else {
-				throw std::logic_error("unexpected bare assignment");
+				donealready = true;
+			}
+			rhs->unlink(anonymous, true);
+			auto nam = rhs->get(name);
+			rhs->unlink(name, nam);
+			if (!donealready) {
+				lhs->links.insert(rhs->links.begin(), rhs->links.end());
 			}
+			rhs->link(name, nam);
+			expr->unlink(value, rhs);
+			dealloc(rhs);
+			dealloc(nam);
+		} else {
+			throw std::logic_error("unexpected bare assignment");
 		}
-	}
+	});
+	ret.r->link(to, *this);
+	ret.r->link(value, that);
+	return ret;
 /*
 	decllnks(anonymous, is, name);
 	declrefs(link, source, type, target, unknown);
@@ -95,49 +132,127 @@ statementevaluable ref::operator=(ref that)
 */
 }
 
-ref ref::operator<<(ref target)
+/*ref ref::operator<<(ref target)
 {
 	// prep a link
 	ref ret = alloc();
 	ret->link(*this, target);
 	return ret;
+}*/
+
+void statementcallref::destatement()
+{
+	auto func = r->get(statement_function);
+	r->unlink(statement_function);
+	dealloc(func);
 }
 
-ref ref::operator[](ref expr) {
-	declrefs(assign, expression);
-	decllnks(value, to);
-	declrefs(link, type, unknown);
+statementcallref::statementcallref(ref type, std::function<void(ref)> func)
+: r(a(type).ptr)
+{
+	r->link(statement_function, valloc<std::function<void(ref)>>(func));
+}
 
-	if (expr.isa(assign-expression)) {
+statementcallref::statementcallref(ref const & that)
+: r(that.ptr)
+{
+	if (!that->linked(statement_function)) {
+		throw std::logic_error(std::string(that) + " has no statement-function");
 	}
-	expr.take();
-	ref lhs = expr.get(to);
-	ref rhs = expr.get(value);
-	if (that.isa(link-type)) {
-		return ::link(*this, that, unknown);
-	} else {
-		ptr->links.insert(that->links.begin(), that->links.end());
-		dealloc(that);
-		return *this;
+}
+
+statementcallref::operator ref()
+{
+	ref ret(r);
+	destatement();
+	r.ptr = 0;
+	return ret;
+}
+
+#include <iostream>
+statementcallref::~statementcallref() noexcept
+{
+	if (r.ptr == 0) { return; }
+	if (r->linked(statement_evaluated, true_ref)) {
+		std::cerr << "statement already evaluated: " << r << std::endl;
+		return;
 	}
+	try {
+		auto func = r->vget<std::function<void(ref)>>(statement_function, true);
+		func->data(r);
+		destatement();
+		r->link(statement_evaluated, true_ref);
+		dealloc(r);
+		r.ptr = 0;
+	} catch (std::out_of_range &) { }
 }
 
-ref operator,(ref a, ref b)
+statementcallref::statementcallref(statementcallref && that) noexcept
+: r(that.r.ptr)
 {
-	a->links.insert(b->links.begin(), b->links.end());
-	dealloc(b);
-	return a;
+	that.r.ptr = 0;
 }
 
-// concept names are for bootstrapping convenience,
-// to make hardcoding structures easier.
-// hence there is just one single list of them
-std::unordered_map<std::string,concept*,std::hash<std::string>,std::equal_to<std::string>> conceptsByName;
+statementcallref::statementcallref(statementcallref & that)
+: r(that.r.ptr)
+{
+	if (that.r.ptr == 0) { throw std::logic_error("empty ref"); }
+	if (that.r->linked(statement_function)) {
+		// statements are moved, for evaluation
+		that.r.ptr = 0;	
+	}
+}
 
-struct name_t : public ref
+ref ref::operator[](ref expr) {
+	declrefs(assign, comma, expression);
+	decllnks(value, to, what);
+	declrefs(link, type, unknown);
+
+	if (expr.isa(assign-expression)) {
+		ref lhs = expr->get(to);
+		ref rhs = expr->get(value);
+		ptr->link(lhs, rhs);
+		dealloc(expr);
+		return *this;
+	} else if (expr.isa(comma-expression)) {
+		auto parts = expr->getAll(what);
+		dealloc(expr);
+		for (ref part : parts) {
+			if (!part.isa(assign-expression)) {
+				throw std::logic_error("[,] argument is not an assignment");
+			}
+			operator[](part);
+		}
+		return *this;
+	} else if (expr.isa(link-type)) {
+		return ::link(*this, expr, unknown);
+	} else {
+		throw std::logic_error("[] argument is neither a link nor an assignment");
+	}
+}
+
+statementcallref operator,(statementcallref a, statementcallref b)
 {
-	name_t();
-} name;
+	declrefs(comma, expression);
+	decllnks(what);
+	if (a.r.isa(comma-expression)) {
+		if (b.r.isa(comma-expression)) {
+			a.r->links.insert(b.r->links.begin(), b.r->links.end());
+			dealloc(b); b.r.ptr = 0;
+		} else {
+			a.r->link(what, b.r); b.r.ptr = 0;
+		}
+		return a;
+	} else if (b.r.isa(comma-expression)) {
+		b.r->link(what, a.r); a.r.ptr = 0;
+		return b;
+	} else {
+		statementcallref ret(comma-expression, [](ref) { throw std::logic_error("bare comma-expression"); });
+		ret.r->link(what, a.r); a.r.ptr = 0;
+		ret.r->link(what, b.r); b.r.ptr = 0;
+		return ret;
+	}
+}
 
 template <>
 vref<std::string>::vref(std::string const & s)
@@ -146,7 +261,7 @@ vref<std::string>::vref(std::string const & s)
 	ptr->link(::name, ptr);
 }
 name_t::name_t()
-: ref(alloc())
+: ref(alloc().ptr)
 {
 	vref nam(std::string("name"));
 	ptr->link(::name, nam);
@@ -171,7 +286,7 @@ vref<std::string> ref::name() const
 {
 	try {
 		return ptr->vget<std::string>(::name, true);
-	} catch (std::out_of_range) {
+	} catch (std::out_of_range &) {
 		declrefs(UNNAMED);
 		return UNNAMED.name();
 	}
@@ -185,7 +300,10 @@ ref a(ref what)
 {
 	static unsigned long long gid = 0;
 	decllnks(is, anonymous);
-	return ref(what.name() + "-" + std::to_string(gid++))[is = what, anonymous = true];
+	ref ret(what.name() + "-" + std::to_string(gid++));
+	ret->link(is, what);
+	ret->link(anonymous, true);
+	return ret;
 }
 ref a(ref what, ref name)
 {