diff --git a/src/runtime/c/pgf/evaluator.c b/src/runtime/c/pgf/evaluator.c
index dcff1e854..3295b81f4 100644
--- a/src/runtime/c/pgf/evaluator.c
+++ b/src/runtime/c/pgf/evaluator.c
@@ -1,17 +1,17 @@
 #include "pgf/pgf.h"
 #include "pgf/data.h"
-#include "pgf/evaluator.h"
+#include "pgf/reasoner.h"
 #include <stdlib.h>
 
 #define PGF_ARGS_DELTA 5
 
 static inline PgfClosure*
-pgf_mk_pap(PgfEvalState* state, PgfClosure* fun,
+pgf_mk_pap(PgfReasoner* rs, PgfClosure* fun,
            size_t n_args, PgfClosure** args)
 {
 	if (n_args > 0) {
-		PgfValuePAP* val = gu_new_flex(state->pool, PgfValuePAP, args, n_args);
-		val->header.code = state->eval_gates->evaluate_value_pap;
+		PgfValuePAP* val = gu_new_flex(rs->pool, PgfValuePAP, args, n_args);
+		val->header.code = rs->eval_gates->evaluate_value_pap;
 		val->fun         = fun;
 		val->n_args      = n_args*sizeof(PgfClosure*);
 		for (size_t i = 0; i < n_args; i++) {
@@ -23,7 +23,7 @@ pgf_mk_pap(PgfEvalState* state, PgfClosure* fun,
 }
 
 PgfClosure*
-pgf_evaluate_expr_thunk(PgfEvalState* state, PgfExprThunk* thunk)
+pgf_evaluate_expr_thunk(PgfReasoner* rs, PgfExprThunk* thunk)
 {
 	PgfEnv* env  = thunk->env;
 	PgfExpr expr = thunk->expr;
@@ -39,7 +39,7 @@ repeat:;
 		PgfExprAbs* eabs = ei.data;
 
 		if (n_args > 0) {
-			PgfEnv* new_env  = gu_new(PgfEnv, state->pool);
+			PgfEnv* new_env  = gu_new(PgfEnv, rs->pool);
 			new_env->next    = env;
 			new_env->closure = args[--n_args];
 
@@ -47,7 +47,7 @@ repeat:;
 			expr = eabs->body;
 			goto repeat;
 		} else {
-			thunk->header.code = state->eval_gates->evaluate_value_lambda;
+			thunk->header.code = rs->eval_gates->evaluate_value_lambda;
 			thunk->expr = eabs->body;
 			res = &thunk->header;
 		}
@@ -56,8 +56,8 @@ repeat:;
 	case PGF_EXPR_APP: {
 		PgfExprApp* eapp = ei.data;
 		PgfExprThunk* thunk = 
-			gu_new(PgfExprThunk, state->pool);
-		thunk->header.code = state->eval_gates->evaluate_expr_thunk;
+			gu_new(PgfExprThunk, rs->pool);
+		thunk->header.code = rs->eval_gates->evaluate_expr_thunk;
 		thunk->env  = env;
 		thunk->expr = eapp->arg;
 		
@@ -72,7 +72,7 @@ repeat:;
 	case PGF_EXPR_LIT: {
 		PgfExprLit* elit = ei.data;
 		PgfValueLit* val = (PgfValueLit*) thunk;
-		val->header.code = state->eval_gates->evaluate_value_lit;
+		val->header.code = rs->eval_gates->evaluate_value_lit;
 		val->lit = elit->lit;
 		res = &val->header;
 		break;
@@ -81,28 +81,28 @@ repeat:;
 		PgfExprMeta* emeta = ei.data;
 
 		PgfValueMeta* val =
-			gu_new(PgfValueMeta, state->pool);
-		val->header.code = state->eval_gates->evaluate_meta;
+			gu_new(PgfValueMeta, rs->pool);
+		val->header.code = rs->eval_gates->evaluate_meta;
 		val->env = env;
 		val->id  = emeta->id;
-		res = pgf_mk_pap(state, &val->header, n_args, args);
+		res = pgf_mk_pap(rs, &val->header, n_args, args);
 		break;
 	}
 	case PGF_EXPR_FUN: {
 		PgfExprFun* efun = ei.data;
 
 		PgfAbsFun* absfun =
-			gu_seq_binsearch(state->pgf->abstract.funs, pgf_absfun_order, PgfAbsFun, efun->fun);
+			gu_seq_binsearch(rs->abstract->funs, pgf_absfun_order, PgfAbsFun, efun->fun);
 		gu_assert(absfun != NULL);
 
 		if (absfun->closure.code != NULL) {
-			res = pgf_mk_pap(state, (PgfClosure*) &absfun->closure, n_args, args);
+			res = pgf_mk_pap(rs, (PgfClosure*) &absfun->closure, n_args, args);
 		} else {
 			size_t arity = absfun->arity;
 
 			if (n_args == arity) {
-				PgfValue* val = gu_new_flex(state->pool, PgfValue, args, arity);
-				val->header.code = state->eval_gates->evaluate_value;
+				PgfValue* val = gu_new_flex(rs->pool, PgfValue, args, arity);
+				val->header.code = rs->eval_gates->evaluate_value;
 				val->con = (PgfClosure*) &absfun->closure;
 
 				for (size_t i = 0; i < arity; i++) {
@@ -112,10 +112,10 @@ repeat:;
 			} else {
 				gu_assert(n_args < arity);
 
-				PgfExprThunk* lambda = gu_new(PgfExprThunk, state->pool);
-				lambda->header.code = state->eval_gates->evaluate_value_lambda;
+				PgfExprThunk* lambda = gu_new(PgfExprThunk, rs->pool);
+				lambda->header.code = rs->eval_gates->evaluate_value_lambda;
 				lambda->env = NULL;
-				res = pgf_mk_pap(state, &lambda->header, n_args, args);
+				res = pgf_mk_pap(rs, &lambda->header, n_args, args);
 
 				for (size_t i = 0; i < arity; i++) {
 					PgfExpr new_expr, arg;
@@ -123,13 +123,13 @@ repeat:;
 					PgfExprVar *evar =
 						gu_new_variant(PGF_EXPR_VAR,
 									   PgfExprVar,
-									   &arg, state->pool);
+									   &arg, rs->pool);
 					evar->var = arity-i-1;
 
 					PgfExprApp *eapp =
 						gu_new_variant(PGF_EXPR_APP,
 									   PgfExprApp,
-									   &new_expr, state->pool);
+									   &new_expr, rs->pool);
 					eapp->fun = expr;
 					eapp->arg = arg;
 					
@@ -142,7 +142,7 @@ repeat:;
 					PgfExprAbs *eabs =
 						gu_new_variant(PGF_EXPR_ABS,
 									   PgfExprAbs,
-									   &new_expr, state->pool);
+									   &new_expr, rs->pool);
 					eabs->bind_type = PGF_BIND_TYPE_EXPLICIT;
 					eabs->id = "_";
 					eabs->body = expr;
@@ -162,7 +162,7 @@ repeat:;
 		while (i > 0) {
 			tmp_env = tmp_env->next;
 			if (tmp_env == NULL) {
-				GuExnData* err_data = gu_raise(state->err, PgfExn);
+				GuExnData* err_data = gu_raise(rs->err, PgfExn);
 				if (err_data) {
 					err_data->data = "invalid de Bruijn index";
 				}
@@ -171,7 +171,7 @@ repeat:;
 			i--;
 		}
 
-		res = pgf_mk_pap(state, tmp_env->closure, n_args, args);
+		res = pgf_mk_pap(rs, tmp_env->closure, n_args, args);
 		break;
 	}
 	case PGF_EXPR_TYPED: {
@@ -193,24 +193,24 @@ repeat:;
 }
 
 PgfClosure*
-pgf_evaluate_lambda_application(PgfEvalState* state, PgfExprThunk* lambda,
-                                                     PgfClosure* arg)
+pgf_evaluate_lambda_application(PgfReasoner* rs, PgfExprThunk* lambda,
+                                PgfClosure* arg)
 {
-	PgfEnv* new_env = gu_new(PgfEnv, state->pool);
+	PgfEnv* new_env = gu_new(PgfEnv, rs->pool);
 	new_env->next    = lambda->env;
 	new_env->closure = arg;
 
-	PgfExprThunk* thunk = gu_new(PgfExprThunk, state->pool);
-	thunk->header.code = state->eval_gates->evaluate_expr_thunk;
+	PgfExprThunk* thunk = gu_new(PgfExprThunk, rs->pool);
+	thunk->header.code = rs->eval_gates->evaluate_expr_thunk;
 	thunk->env         = new_env;
 	thunk->expr        = lambda->expr;
-	return pgf_evaluate_expr_thunk(state, thunk);
+	return pgf_evaluate_expr_thunk(rs, thunk);
 }
 
 static PgfExpr
-pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
+pgf_value2expr(PgfReasoner* rs, int level, PgfClosure* clos)
 {
-	clos = state->eval_gates->enter(state, clos);
+	clos = rs->eval_gates->enter(rs, clos);
 	if (clos == NULL)
 		return gu_null_variant;
 
@@ -218,20 +218,20 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 	size_t n_args = 0;
 	PgfClosure** args;
 
-	if (clos->code == state->eval_gates->evaluate_value) {
+	if (clos->code == rs->eval_gates->evaluate_value) {
 		PgfValue* val = (PgfValue*) clos;
 		PgfAbsFun* absfun = gu_container(val->con, PgfAbsFun, closure);
 
 		expr   = absfun->ep.expr;
 		n_args = absfun->arity;
 		args   = val->args;
-	} else if (clos->code == state->eval_gates->evaluate_value_lit) {
+	} else if (clos->code == rs->eval_gates->evaluate_value_lit) {
 		PgfValueLit* val = (PgfValueLit*) clos;
 
 		PgfExprLit *elit =
 			gu_new_variant(PGF_EXPR_LIT,
 						   PgfExprLit,
-						   &expr, pool);
+						   &expr, rs->out_pool);
 
 		GuVariantInfo i = gu_variant_open(val->lit);
 		switch (i.tag) {
@@ -242,7 +242,7 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 				gu_new_flex_variant(PGF_LITERAL_STR,
 									PgfLiteralStr,
 									val, strlen(lstr->val)+1,
-									&elit->lit, pool);
+									&elit->lit, rs->out_pool);
 			strcpy(new_lstr->val, lstr->val);
 			break;
 		}
@@ -252,7 +252,7 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 			PgfLiteralInt* new_lint =
 				gu_new_variant(PGF_LITERAL_INT,
 							   PgfLiteralInt,
-							   &elit->lit, pool);
+							   &elit->lit, rs->out_pool);
 			new_lint->val = lint->val;
 			break;
 		}
@@ -262,24 +262,24 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 			PgfLiteralFlt* new_lflt =
 				gu_new_variant(PGF_LITERAL_FLT,
 							   PgfLiteralFlt,
-							   &elit->lit, pool);
+							   &elit->lit, rs->out_pool);
 			new_lflt->val = lflt->val;
 			break;
 		}
 		default:
 			gu_impossible();
 		}
-	} else if (clos->code == state->eval_gates->evaluate_value_pap) {
+	} else if (clos->code == rs->eval_gates->evaluate_value_pap) {
 		PgfValuePAP *pap = (PgfValuePAP*) clos;
 
 		PgfValueGen* gen =
-			gu_new(PgfValueGen, state->pool);
-		gen->header.code = state->eval_gates->evaluate_gen;
+			gu_new(PgfValueGen, rs->pool);
+		gen->header.code = rs->eval_gates->evaluate_gen;
 		gen->level  = level;
 
 		size_t n_args = pap->n_args/sizeof(PgfClosure*);
-		PgfValuePAP* new_pap = gu_new_flex(state->pool, PgfValuePAP, args, n_args+1);
-		new_pap->header.code = state->eval_gates->evaluate_value_pap;
+		PgfValuePAP* new_pap = gu_new_flex(rs->pool, PgfValuePAP, args, n_args+1);
+		new_pap->header.code = rs->eval_gates->evaluate_value_pap;
 		new_pap->fun         = pap->fun;
 		new_pap->n_args      = pap->n_args+sizeof(PgfClosure*);
 		new_pap->args[0]     = &gen->header;
@@ -290,30 +290,30 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 		PgfExprAbs *eabs =
 			gu_new_variant(PGF_EXPR_ABS,
 						   PgfExprAbs,
-						   &expr, pool);
+						   &expr, rs->out_pool);
 		eabs->bind_type = PGF_BIND_TYPE_EXPLICIT;
-		eabs->id = gu_format_string(pool, "v%d", level);
-		eabs->body = pgf_value2expr(state, level+1, &new_pap->header, pool);
-	} else if (clos->code == state->eval_gates->evaluate_value_const) {
+		eabs->id = gu_format_string(rs->out_pool, "v%d", level);
+		eabs->body = pgf_value2expr(rs, level+1, &new_pap->header);
+	} else if (clos->code == rs->eval_gates->evaluate_value_const) {
 		PgfValuePAP* val = (PgfValuePAP*) clos;
 		
-		if (val->fun->code == state->eval_gates->evaluate_meta) {
+		if (val->fun->code == rs->eval_gates->evaluate_meta) {
 			PgfValueMeta* fun = (PgfValueMeta*) val->fun;
 
 			PgfExprMeta *emeta =
 				gu_new_variant(PGF_EXPR_META,
 				               PgfExprMeta,
-				               &expr, pool);
+				               &expr, rs->out_pool);
 			emeta->id = fun->id;
-		} else if (val->fun->code == state->eval_gates->evaluate_gen) {
+		} else if (val->fun->code == rs->eval_gates->evaluate_gen) {
 			PgfValueGen* fun = (PgfValueGen*) val->fun;
 
 			PgfExprVar *evar =
 				gu_new_variant(PGF_EXPR_VAR,
 				               PgfExprVar,
-				               &expr, pool);
+				               &expr, rs->out_pool);
 			evar->var = level - fun->level - 1;
-		} else if (val->fun->code == state->eval_gates->evaluate_sum) {
+		} else if (val->fun->code == rs->eval_gates->evaluate_sum) {
 			PgfValueSum* sum = (PgfValueSum*) val->fun;
 
 			PgfExpr e1,e2;
@@ -321,19 +321,19 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 				gu_new_flex_variant(PGF_EXPR_FUN,
 				                    PgfExprFun,
 				                    fun, 2,
-				                    &e1, pool);
+				                    &e1, rs->out_pool);
 			strcpy(efun->fun, "+");
 
 			PgfExprLit *elit =
 				gu_new_variant(PGF_EXPR_LIT,
 				               PgfExprLit,
-				               &e2, pool);
+				               &e2, rs->out_pool);
 			elit->lit = sum->lit;
 			
 			PgfExprApp* eapp =
 				gu_new_variant(PGF_EXPR_APP,
 				               PgfExprApp,
-				               &expr, pool);
+				               &expr, rs->out_pool);
 			eapp->fun = e1;
 			eapp->arg = e2;
 	
@@ -344,14 +344,14 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 
 				PgfExpr fun = expr;
 				PgfExpr arg = 
-					pgf_value2expr(state, level, con, pool);
+					pgf_value2expr(rs, level, con);
 				if (gu_variant_is_null(arg))
 					return gu_null_variant;
 
 				PgfExprApp* e =
 					gu_new_variant(PGF_EXPR_APP,
 					               PgfExprApp,
-					               &expr, pool);
+					               &expr, rs->out_pool);
 				e->fun = fun;
 				e->arg = arg;
 			}
@@ -369,14 +369,14 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 	for (size_t i = 0; i < n_args; i++) {
 		PgfExpr fun = expr;
 		PgfExpr arg = 
-			pgf_value2expr(state, level, args[i], pool);
+			pgf_value2expr(rs, level, args[i]);
 		if (gu_variant_is_null(arg))
 			return gu_null_variant;
 
 		PgfExprApp* e =
 			gu_new_variant(PGF_EXPR_APP,
 						   PgfExprApp,
-						   &expr, pool);
+						   &expr, rs->out_pool);
 		e->fun = fun;
 		e->arg = arg;
 	}
@@ -387,47 +387,33 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 PgfExpr
 pgf_compute(PgfPGF* pgf, PgfExpr expr, GuExn* err, GuPool* pool, GuPool* out_pool)
 {
-	size_t n_cafs =
-		(pgf->abstract.eval_gates->cafs == NULL) 
-			? 0 : gu_seq_length(pgf->abstract.eval_gates->cafs);
-
-	PgfEvalState* state = 
-		gu_new_flex(pool, PgfEvalState, cafs, n_cafs);
-	state->pgf   = pgf;
-	state->eval_gates = pgf->abstract.eval_gates;
-	state->pool  = pool;
-	state->err   = err;
-
-	PgfFunction* cafs = gu_seq_data(state->eval_gates->cafs);
-	for (size_t i = 0; i < n_cafs; i++) {
-		state->cafs[i].header.code = cafs[i];
-		state->cafs[i].val = NULL;
-	}
+	PgfReasoner* rs =
+		pgf_new_reasoner(pgf, err, pool, out_pool);
 
 	PgfExprThunk* thunk =
 		gu_new(PgfExprThunk, pool);
-	thunk->header.code = state->eval_gates->evaluate_expr_thunk;
+	thunk->header.code = rs->eval_gates->evaluate_expr_thunk;
 	thunk->env  = NULL;
 	thunk->expr = expr;
 
-	return pgf_value2expr(state, 0, &thunk->header, out_pool);
+	return pgf_value2expr(rs, 0, &thunk->header);
 }
 
 void
-pgf_evaluate_accum_init_int(PgfEvalState* state, 
+pgf_evaluate_accum_init_int(PgfReasoner* rs, 
                             PgfEvalAccum* accum, int val)
 {
 	PgfLiteralInt *lit_int =
 		gu_new_variant(PGF_LITERAL_INT,
 	                   PgfLiteralInt,
 	                   &accum->lit,
-					   state->pool);
+					   rs->pool);
 	lit_int->val = val;
 	accum->consts = NULL;
 }
 
 void
-pgf_evaluate_accum_init_str(PgfEvalState* state, 
+pgf_evaluate_accum_init_str(PgfReasoner* rs, 
                             PgfEvalAccum* accum, GuString val)
 {
 	if (val == NULL)
@@ -437,23 +423,23 @@ pgf_evaluate_accum_init_str(PgfEvalState* state,
 		gu_new_flex_variant(PGF_LITERAL_STR,
 							PgfLiteralStr,
 							val, strlen(val)+1,
-							&accum->lit, state->pool);
+							&accum->lit, rs->pool);
 	strcpy((char*) lit_str->val, (char*) val);
 	accum->consts = NULL;
 }
 
 void
-pgf_evaluate_accum_init_flt(PgfEvalState* state, 
+pgf_evaluate_accum_init_flt(PgfReasoner* rs, 
                             PgfEvalAccum* accum, float val)
 {
 	PgfLiteralFlt *lit_flt =
 		gu_new_variant(PGF_LITERAL_FLT,
 					   PgfLiteralFlt,
 					   &accum->lit,
-					   state->pool);
+					   rs->pool);
 	lit_flt->val = val;
-	accum->enter_stack_ptr = state->enter_stack_ptr;
-	state->enter_stack_ptr = ((void*)accum)-sizeof(void*)*2;
+	accum->enter_stack_ptr = rs->enter_stack_ptr;
+	rs->enter_stack_ptr = ((void*)accum)-sizeof(void*)*2;
 	accum->consts = NULL;
 }
 
@@ -480,19 +466,19 @@ pgf_evaluate_accum_add_helper(PgfEvalAccum* accum, PgfLiteral lit)
 }
 
 void
-pgf_evaluate_accum_add(PgfEvalState* state,
+pgf_evaluate_accum_add(PgfReasoner* rs,
                        PgfEvalAccum* accum, PgfClosure* closure)
 {
-	if (closure->code == state->eval_gates->evaluate_value_lit) {
+	if (closure->code == rs->eval_gates->evaluate_value_lit) {
 		PgfValueLit* val = (PgfValueLit*) closure;
 		pgf_evaluate_accum_add_helper(accum, val->lit);
-	} else if (closure->code == state->eval_gates->evaluate_value_const) {
+	} else if (closure->code == rs->eval_gates->evaluate_value_const) {
 		if (accum->consts == NULL)
-			accum->consts = gu_new_buf(PgfClosure*, state->pool);
+			accum->consts = gu_new_buf(PgfClosure*, rs->pool);
 
 		PgfValuePAP* pap = (PgfValuePAP*) closure;
 		
-		if (pap->fun->code == state->eval_gates->evaluate_sum) {
+		if (pap->fun->code == rs->eval_gates->evaluate_sum) {
 			PgfValueSum* val = (PgfValueSum*) ((PgfValuePAP*) closure)->fun;
 			pgf_evaluate_accum_add_helper(accum, val->lit);
 
@@ -510,18 +496,18 @@ pgf_evaluate_accum_add(PgfEvalState* state,
 }
 
 PgfClosure*
-pgf_evaluate_accum_done(PgfEvalState* state, PgfEvalAccum* accum)
+pgf_evaluate_accum_done(PgfReasoner* rs, PgfEvalAccum* accum)
 {
-	state->enter_stack_ptr = accum->enter_stack_ptr;
+	rs->enter_stack_ptr = accum->enter_stack_ptr;
 
 	if (accum->consts == NULL) {
-		PgfValueLit* val = gu_new(PgfValueLit, state->pool);
-		val->header.code = state->eval_gates->evaluate_value_lit;
+		PgfValueLit* val = gu_new(PgfValueLit, rs->pool);
+		val->header.code = rs->eval_gates->evaluate_value_lit;
 		val->lit = accum->lit;
 		return &val->header;
 	} else {
-		PgfValueSum* val = gu_new(PgfValueSum, state->pool);
-		val->header.code = state->eval_gates->evaluate_sum;
+		PgfValueSum* val = gu_new(PgfValueSum, rs->pool);
+		val->header.code = rs->eval_gates->evaluate_sum;
 		val->lit = accum->lit;
 		val->consts = accum->consts;
 		return &val->header;
diff --git a/src/runtime/c/pgf/evaluator.h b/src/runtime/c/pgf/evaluator.h
deleted file mode 100644
index 39d43559d..000000000
--- a/src/runtime/c/pgf/evaluator.h
+++ /dev/null
@@ -1,127 +0,0 @@
-#ifndef PGF_EVALUATOR_H_
-#define PGF_EVALUATOR_H_
-
-typedef struct {
-	PgfFunction code;
-} PgfClosure;
-
-typedef struct {
-	PgfClosure header;
-	PgfClosure* val;
-} PgfIndirection;
-
-typedef struct {
-	PgfPGF* pgf;
-	PgfEvalGates* eval_gates; // cached from pgf->abstr->eval_gates
-	GuPool* pool;
-	GuExn* err;
-	void* enter_stack_ptr;
-	void* tmp;              // for temporary register spills
-	PgfIndirection cafs[];  // derived from gu_seq_data(pgf->abstr->eval_gates->cafs)
-} PgfEvalState;
-
-typedef struct {
-	PgfLiteral lit;
-	GuBuf* consts;
-	void* enter_stack_ptr;
-} PgfEvalAccum;
-
-typedef struct PgfEnv PgfEnv;
-
-struct PgfEnv {
-	PgfEnv* next;
-	PgfClosure* closure;
-};
-
-typedef struct {
-	PgfClosure header;
-	PgfEnv*  env;
-	PgfExpr  expr;
-} PgfExprThunk;
-
-typedef struct {
-	PgfClosure header;
-	PgfClosure* con;
-	PgfClosure* args[];
-} PgfValue;
-
-typedef struct {
-	PgfClosure header;
-	int level;
-} PgfValueGen;
-
-typedef struct {
-	PgfClosure header;
-	PgfEnv*  env;
-	PgfMetaId id;
-} PgfValueMeta;
-
-typedef struct {
-	PgfClosure header;
-	PgfLiteral lit;
-} PgfValueLit;
-
-typedef struct {
-	PgfClosure header;
-	PgfLiteral lit;
-	GuBuf* consts;
-} PgfValueSum;
-
-typedef struct {
-	PgfClosure header;
-	PgfClosure* fun;
-	size_t      n_args;
-	PgfClosure* args[];
-} PgfValuePAP;
-
-struct PgfEvalGates {
-	PgfFunction evaluate_expr_thunk;
-	PgfFunction evaluate_indirection;
-	PgfFunction evaluate_value;
-	PgfFunction evaluate_value_lit;
-	PgfFunction evaluate_value_pap;
-	PgfFunction evaluate_value_lambda;
-	PgfFunction evaluate_value_const;
-	PgfFunction evaluate_meta;
-	PgfFunction evaluate_gen;
-	PgfFunction evaluate_sum;
-	PgfFunction evaluate_caf;
-
-	PgfFunction update_closure;
-	PgfFunction update_pap;
-
-	PgfFunction mk_const;
-
-	PgfClosure* (*enter)(PgfEvalState* state, PgfClosure* closure);
-
-	GuFinalizer fin;
-	GuSeq* cafs;
-};
-
-PgfClosure*
-pgf_evaluate_expr_thunk(PgfEvalState* state, PgfExprThunk* thunk);
-
-PgfClosure*
-pgf_evaluate_lambda_application(PgfEvalState* state, PgfExprThunk* lambda,
-                                                     PgfClosure* arg);
-
-void
-pgf_evaluate_accum_init_int(PgfEvalState* state, 
-                            PgfEvalAccum* accum, int val);
-
-void
-pgf_evaluate_accum_init_str(PgfEvalState* state, 
-                            PgfEvalAccum* accum, GuString val);
-                            
-void
-pgf_evaluate_accum_init_flt(PgfEvalState* state, 
-                            PgfEvalAccum* accum, float val);
-
-void
-pgf_evaluate_accum_add(PgfEvalState* state, 
-                       PgfEvalAccum* accum, PgfClosure* closure);
-
-PgfClosure*
-pgf_evaluate_accum_done(PgfEvalState* state, PgfEvalAccum* accum);
-
-#endif
diff --git a/src/runtime/c/pgf/hopu.c b/src/runtime/c/pgf/hopu.c
index 5767feac0..d94804625 100644
--- a/src/runtime/c/pgf/hopu.c
+++ b/src/runtime/c/pgf/hopu.c
@@ -1,10 +1,10 @@
 #include "data.h"
-#include "evaluator.h"
+#include "reasoner.h"
 #include "hopu.h"
 
-void pgf_pattern_unify(PgfEvalState* state, PgfClosure* c1, PgfClosure* c2)
+void pgf_pattern_unify(PgfReasoner* rs, PgfClosure* c1, PgfClosure* c2)
 {
-	c1 = state->eval_gates->enter(state, c1);
-	c2 = state->eval_gates->enter(state, c2);
+	c1 = rs->eval_gates->enter(rs, c1);
+	c2 = rs->eval_gates->enter(rs, c2);
 }
 
diff --git a/src/runtime/c/pgf/hopu.h b/src/runtime/c/pgf/hopu.h
index e012a3630..a2dfa6649 100644
--- a/src/runtime/c/pgf/hopu.h
+++ b/src/runtime/c/pgf/hopu.h
@@ -1,7 +1,7 @@
 #ifndef HOPU_H
 #define HOPU_H
 
-void pgf_pattern_unify(PgfEvalState* state, PgfClosure* c1, PgfClosure* c2);
+void pgf_pattern_unify(PgfReasoner* rs, PgfClosure* c1, PgfClosure* c2);
 
 #endif
 
diff --git a/src/runtime/c/pgf/jit.c b/src/runtime/c/pgf/jit.c
index 35ef3ca05..53b1d8756 100644
--- a/src/runtime/c/pgf/jit.c
+++ b/src/runtime/c/pgf/jit.c
@@ -3,7 +3,6 @@
 #include <gu/utf8.h>
 #include <pgf/data.h>
 #include <pgf/reasoner.h>
-#include <pgf/evaluator.h>
 #include <pgf/reader.h>
 #include "lightning.h"
 #ifdef __MINGW32__
@@ -387,7 +386,7 @@ pgf_jit_gates(PgfReader* rdr)
 	int closure_arg = jit_arg_p();
 	jit_getarg_p(JIT_VSTATE, es_arg);
 	jit_getarg_p(JIT_VCLOS,  closure_arg);
-	jit_stxi_p(offsetof(PgfEvalState, enter_stack_ptr), JIT_VSTATE, JIT_SP);
+	jit_stxi_p(offsetof(PgfReasoner, enter_stack_ptr), JIT_VSTATE, JIT_SP);
 	jit_ldr_p(JIT_R0, JIT_VCLOS);
 	jit_callr(JIT_R0);
 	jit_movr_p(JIT_RET, JIT_VHEAP);
@@ -430,7 +429,7 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_prepare(2);
 	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValuePAP));
 	jit_pusharg_ui(JIT_R0);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
+	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfReasoner,pool));
 	jit_pusharg_p(JIT_R0);
 	jit_finish(gu_malloc);
 	jit_popr_i(JIT_R1);
@@ -531,7 +530,7 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_prepare(2);
 	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValuePAP));
 	jit_pusharg_ui(JIT_R0);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
+	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfReasoner,pool));
 	jit_pusharg_p(JIT_R0);
 	jit_finish(gu_malloc);
 	jit_popr_i(JIT_R1);
@@ -563,15 +562,15 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_pushr_p(JIT_R0);
 	jit_jmpi(gates->mk_const);
 	jit_patch(ref2);
-	jit_ldxi_p(JIT_R1, JIT_VSTATE, offsetof(PgfEvalState,enter_stack_ptr));
+	jit_ldxi_p(JIT_R1, JIT_VSTATE, offsetof(PgfReasoner,enter_stack_ptr));
 	ref2 = jit_bner_p(jit_forward(), JIT_FP, JIT_R1);
-	jit_stxi_p(offsetof(PgfEvalState,tmp), JIT_VSTATE, JIT_R0);
+	jit_stxi_p(offsetof(PgfReasoner,tmp), JIT_VSTATE, JIT_R0);
 	jit_subr_p(JIT_R0, JIT_FP, JIT_SP);
 	jit_pushr_i(JIT_R0);
 	jit_prepare(2);
 	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValuePAP));
 	jit_pusharg_ui(JIT_R0);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
+	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfReasoner,pool));
 	jit_pusharg_p(JIT_R0);
 	jit_finish(gu_malloc);
 	jit_movr_p(JIT_VHEAP, JIT_RET);
@@ -588,7 +587,7 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_subi_i(JIT_R1, JIT_R1, sizeof(void*));
 	jit_jmpi(next);
 	jit_patch(ref);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,tmp));
+	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfReasoner,tmp));
 	jit_jmpr(JIT_R0);
 	jit_patch(ref2);
 	jit_ldxi_p(JIT_VCLOS, JIT_FP, sizeof(void*));
@@ -662,7 +661,7 @@ pgf_jit_function(PgfReader* rdr, PgfAbstr* abstr,
 				absfun->closure.code = abstr->eval_gates->evaluate_caf;
 				size_t caf_id = rdr->jit_state->n_cafs++;
 				absfun->closure.caf_offset = 
-					offsetof(PgfEvalState,cafs)+
+					offsetof(PgfReasoner,cafs)+
 					caf_id*sizeof(PgfIndirection);
 				gu_seq_set(abstr->eval_gates->cafs,
 				           PgfFunction,
@@ -807,7 +806,7 @@ pgf_jit_function(PgfReader* rdr, PgfAbstr* abstr,
 				jit_prepare(2);
 				jit_movi_ui(JIT_R0, size*sizeof(void*));
 				jit_pusharg_ui(JIT_R0);
-				jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
+				jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfReasoner,pool));
 				jit_pusharg_p(JIT_R0);
 				jit_finish(gu_malloc);
 				jit_retval_p(JIT_VHEAP);
diff --git a/src/runtime/c/pgf/pgf.h b/src/runtime/c/pgf/pgf.h
index 3e2e88006..80cbe29f2 100644
--- a/src/runtime/c/pgf/pgf.h
+++ b/src/runtime/c/pgf/pgf.h
@@ -90,16 +90,16 @@ pgf_parseval(PgfConcr* concr, PgfExpr expr, PgfCId cat,
              double *precision, double *recall, double *exact);
 
 PgfExpr
-pgf_compute(PgfPGF* pgf, PgfExpr expr, GuExn* err, 
+pgf_compute(PgfPGF* pgf, PgfExpr expr, GuExn* err,
             GuPool* pool, GuPool* out_pool);
 
 PgfExprEnum*
-pgf_generate_all(PgfPGF* pgf, PgfCId cat, GuPool* pool);
+pgf_generate_all(PgfPGF* pgf, PgfCId cat,
+                 GuExn* err, GuPool* pool, GuPool* out_pool);
 
 PgfExprEnum*
 pgf_parse(PgfConcr* concr, PgfCId cat, GuString sentence,
-          GuExn* err,
-          GuPool* pool, GuPool* out_pool);
+          GuExn* err, GuPool* pool, GuPool* out_pool);
 
 typedef struct PgfMorphoCallback PgfMorphoCallback;
 struct PgfMorphoCallback {
diff --git a/src/runtime/c/pgf/reader.c b/src/runtime/c/pgf/reader.c
index f8b4d198e..cb690a353 100644
--- a/src/runtime/c/pgf/reader.c
+++ b/src/runtime/c/pgf/reader.c
@@ -1,6 +1,6 @@
 #include "data.h"
 #include "expr.h"
-#include "evaluator.h"
+#include "reasoner.h"
 #include "reader.h"
 
 #include <gu/defs.h>
diff --git a/src/runtime/c/pgf/reader.h b/src/runtime/c/pgf/reader.h
index 38d691817..4280d1138 100644
--- a/src/runtime/c/pgf/reader.h
+++ b/src/runtime/c/pgf/reader.h
@@ -48,7 +48,7 @@ pgf_reader_done(PgfReader* rdr, PgfPGF* pgf);
 
 
 // JIT specific interface
-#ifdef PGF_EVALUATOR_H_
+#ifdef PGF_REASONER_H_
 
 typedef struct PgfJitState PgfJitState;
 
diff --git a/src/runtime/c/pgf/reasoner.c b/src/runtime/c/pgf/reasoner.c
index 352ca5ecd..dfc8905ac 100644
--- a/src/runtime/c/pgf/reasoner.c
+++ b/src/runtime/c/pgf/reasoner.c
@@ -58,18 +58,6 @@ typedef struct {
 	size_t choice;
 } PgfCombine2State;
 
-typedef GuStringMap PgfAbswersMap;
-
-struct PgfReasoner {
-	GuPool* pool;
-	GuPool* tmp_pool;
-	PgfAbstr* abstract;
-	PgfAbswersMap* table;
-	GuBuf* pqueue;
-	GuBuf* exprs;
-	PgfExprEnum en;
-};
-
 static int
 cmp_expr_state(GuOrder* self, const void* a, const void* b)
 {
@@ -136,16 +124,16 @@ pgf_print_expr_state(PgfExprState* st,
 #endif
 
 static PgfExprState*
-pgf_combine1_to_expr(PgfCombine1State* st, GuPool* tmp_pool) {
+pgf_combine1_to_expr(PgfCombine1State* st, GuPool* pool, GuPool* out_pool) {
 	PgfExprProb* ep =
 		gu_buf_get(st->exprs, PgfExprProb*, st->choice);
 
-	PgfExprState* nst = gu_new(PgfExprState, tmp_pool);
+	PgfExprState* nst = gu_new(PgfExprState, pool);
 	nst->base.continuation = st->parent->base.continuation;
 	nst->base.prob = st->base.prob;
 	nst->answers = st->parent->answers;
 	nst->expr =
-		gu_new_variant_i(tmp_pool, PGF_EXPR_APP,
+		gu_new_variant_i(out_pool, PGF_EXPR_APP,
 				PgfExprApp,
 				.fun = st->parent->expr,
 				.arg = ep->expr);
@@ -159,7 +147,7 @@ pgf_combine1_to_expr(PgfCombine1State* st, GuPool* tmp_pool) {
 }
 
 static PgfExprState*
-pgf_combine2_to_expr(PgfCombine2State* st, GuPool* tmp_pool)
+pgf_combine2_to_expr(PgfCombine2State* st, GuPool* pool, GuPool* out_pool)
 {
 	PgfExprState* parent =
 		gu_buf_get(st->parents, PgfExprState*, st->choice);
@@ -167,12 +155,12 @@ pgf_combine2_to_expr(PgfCombine2State* st, GuPool* tmp_pool)
 		return NULL;
 
 	PgfExprState* nst =
-		gu_new(PgfExprState, tmp_pool);
+		gu_new(PgfExprState, pool);
 	nst->base.continuation = parent->base.continuation;
 	nst->base.prob         = st->base.prob;
 	nst->answers = parent->answers;
 	nst->expr    =
-		gu_new_variant_i(tmp_pool, PGF_EXPR_APP,
+		gu_new_variant_i(out_pool, PGF_EXPR_APP,
 				PgfExprApp,
 				.fun = parent->expr,
 				.arg = st->ep->expr);
@@ -190,7 +178,7 @@ static void
 pgf_print_combine1_state(PgfCombine1State* st,
                          GuOut* out, GuExn* err, GuPool* tmp_pool)
 {
-	PgfExprState* nst = pgf_combine1_to_expr(st, tmp_pool);
+	PgfExprState* nst = pgf_combine1_to_expr(st, tmp_pool, tmp_pool);
 	pgf_print_expr_state(nst, out, err, tmp_pool);
 }
 
@@ -207,7 +195,7 @@ pgf_print_combine2_state(PgfCombine2State* st,
 static void
 pgf_combine1(PgfReasoner* rs, PgfCombine1State* st)
 {
-	PgfExprState* nst = pgf_combine1_to_expr(st, rs->tmp_pool);
+	PgfExprState* nst = pgf_combine1_to_expr(st, rs->pool, rs->out_pool);
 	nst->base.continuation(rs, &nst->base);
 
 	st->choice++;
@@ -228,9 +216,9 @@ pgf_reasoner_try_first(PgfReasoner* rs, PgfExprState* parent, PgfAbsFun* absfun)
 
 	PgfAnswers* answers = gu_map_get(rs->table, cat, PgfAnswers*);
 	if (answers == NULL) {
-		answers = gu_new(PgfAnswers, rs->tmp_pool);
-		answers->parents = gu_new_buf(PgfExprState*, rs->tmp_pool);
-		answers->exprs   = gu_new_buf(PgfExprProb*, rs->tmp_pool);
+		answers = gu_new(PgfAnswers, rs->pool);
+		answers->parents = gu_new_buf(PgfExprState*, rs->pool);
+		answers->exprs   = gu_new_buf(PgfExprProb*, rs->pool);
 		answers->outside_prob = parent->base.prob;
 
 		gu_map_put(rs->table, cat, PgfAnswers*, answers);
@@ -239,7 +227,7 @@ pgf_reasoner_try_first(PgfReasoner* rs, PgfExprState* parent, PgfAbsFun* absfun)
 	gu_buf_push(answers->parents, PgfExprState*, parent);
 
 	if (gu_buf_length(answers->parents) == 1) {
-		PgfExprState* st = gu_new(PgfExprState, rs->tmp_pool);
+		PgfExprState* st = gu_new(PgfExprState, rs->pool);
 		st->base.continuation = (PgfPredicate) absfun->predicate;
 		st->base.prob = answers->outside_prob + absfun->ep.prob;
 		st->answers = answers;
@@ -256,7 +244,7 @@ pgf_reasoner_try_first(PgfReasoner* rs, PgfExprState* parent, PgfAbsFun* absfun)
 			PgfExprProb* ep =
 				gu_buf_get(answers->exprs, PgfExprProb*, 0);
 
-			PgfCombine1State* nst = gu_new(PgfCombine1State, rs->tmp_pool);
+			PgfCombine1State* nst = gu_new(PgfCombine1State, rs->pool);
 			nst->base.continuation = (PgfPredicate) pgf_combine1;
 			nst->base.prob         = parent->base.prob + ep->prob;
 			nst->exprs             = answers->exprs;
@@ -274,7 +262,7 @@ pgf_reasoner_try_first(PgfReasoner* rs, PgfExprState* parent, PgfAbsFun* absfun)
 void
 pgf_reasoner_try_else(PgfReasoner* rs, PgfExprState* prev, PgfAbsFun* absfun)
 {
-	PgfExprState *st = gu_new(PgfExprState, rs->tmp_pool);
+	PgfExprState *st = gu_new(PgfExprState, rs->pool);
 	st->base.continuation = (PgfPredicate) absfun->predicate;
 	st->base.prob = prev->answers->outside_prob + absfun->ep.prob;
 	st->answers   = prev->answers;
@@ -290,7 +278,7 @@ pgf_reasoner_try_else(PgfReasoner* rs, PgfExprState* prev, PgfAbsFun* absfun)
 static void
 pgf_combine2(PgfReasoner* rs, PgfCombine2State* st)
 {
-	PgfExprState* nst = pgf_combine2_to_expr(st, rs->tmp_pool);
+	PgfExprState* nst = pgf_combine2_to_expr(st, rs->pool, rs->out_pool);
 	if (nst != NULL) {
 		nst->base.continuation(rs, &nst->base);
 	}
@@ -309,12 +297,12 @@ pgf_combine2(PgfReasoner* rs, PgfCombine2State* st)
 void
 pgf_reasoner_complete(PgfReasoner* rs, PgfExprState* st)
 {
-	PgfExprProb* ep = gu_new(PgfExprProb, rs->pool);
+	PgfExprProb* ep = gu_new(PgfExprProb, rs->out_pool);
 	ep->prob = st->base.prob - st->answers->outside_prob;
 	ep->expr = st->expr;
 	gu_buf_push(st->answers->exprs, PgfExprProb*, ep);
 
-	PgfCombine2State* nst = gu_new(PgfCombine2State, rs->tmp_pool);
+	PgfCombine2State* nst = gu_new(PgfCombine2State, rs->pool);
 	nst->base.continuation = (PgfPredicate) pgf_combine2;
 	nst->base.prob         = st->base.prob;
 	nst->parents           = st->answers->parents;
@@ -336,10 +324,7 @@ pgf_reasoner_try_constant(PgfReasoner* rs, PgfExprState* prev, PgfAbsFun* absfun
 
 static PgfExprProb*
 pgf_reasoner_next(PgfReasoner* rs)
-{
-	if (rs->tmp_pool == NULL)
-		return NULL;
-		
+{		
 	size_t n_exprs = gu_buf_length(rs->exprs);
 
 	while (gu_buf_length(rs->pqueue) > 0) {
@@ -363,9 +348,6 @@ pgf_reasoner_next(PgfReasoner* rs)
 		}
 	}
 
-	gu_pool_free(rs->tmp_pool);
-	rs->tmp_pool = NULL;
-	rs->pqueue   = NULL;
 	return NULL;
 }
 
@@ -376,21 +358,42 @@ pgf_reasoner_enum_next(GuEnum* self, void* to, GuPool* pool)
 	*(PgfExprProb**)to = pgf_reasoner_next(pr);
 }
 
-PgfExprEnum*
-pgf_generate_all(PgfPGF* pgf, PgfCId cat, GuPool* pool)
+PgfReasoner*
+pgf_new_reasoner(PgfPGF* pgf, GuExn* err, GuPool* pool, GuPool* out_pool)
 {
-	PgfReasoner* rs = gu_new(PgfReasoner, pool);
-	rs->pool = pool;
-	rs->tmp_pool = gu_new_pool(),
-    rs->abstract = &pgf->abstract,
-	rs->table = gu_new_string_map(PgfAnswers*, &gu_null_struct, rs->tmp_pool),
+	size_t n_cafs =
+		(pgf->abstract.eval_gates->cafs == NULL) 
+			? 0 : gu_seq_length(pgf->abstract.eval_gates->cafs);
 
-	rs->pqueue = gu_new_buf(PgfReasonerState*, rs->tmp_pool);
-	rs->exprs = gu_new_buf(PgfExprProb*, rs->tmp_pool);
+	PgfReasoner* rs = gu_new_flex(pool, PgfReasoner, cafs, n_cafs);
+	rs->pool = pool,
+	rs->out_pool = out_pool;
+	rs->err   = err;
+    rs->abstract = &pgf->abstract,
+	rs->table = gu_new_string_map(PgfAnswers*, &gu_null_struct, rs->pool),
+
+	rs->eval_gates = pgf->abstract.eval_gates;
+
+	rs->pqueue = gu_new_buf(PgfReasonerState*, rs->pool);
+	rs->exprs = gu_new_buf(PgfExprProb*, rs->pool);
 	rs->en.next = pgf_reasoner_enum_next;
 
-	PgfAnswers* answers = gu_new(PgfAnswers, rs->tmp_pool);
-	answers->parents = gu_new_buf(PgfExprState*, rs->tmp_pool);
+	PgfFunction* cafs = gu_seq_data(rs->eval_gates->cafs);
+	for (size_t i = 0; i < n_cafs; i++) {
+		rs->cafs[i].header.code = cafs[i];
+		rs->cafs[i].val = NULL;
+	}
+
+	return rs;
+}
+
+PgfExprEnum*
+pgf_generate_all(PgfPGF* pgf, PgfCId cat, GuExn* err, GuPool* pool, GuPool* out_pool)
+{
+	PgfReasoner* rs = pgf_new_reasoner(pgf, err, pool, out_pool);
+
+	PgfAnswers* answers = gu_new(PgfAnswers, rs->pool);
+	answers->parents = gu_new_buf(PgfExprState*, rs->pool);
 	answers->exprs   = rs->exprs;
 	answers->outside_prob = 0;
 	gu_map_put(rs->table, cat, PgfAnswers*, answers);
diff --git a/src/runtime/c/pgf/reasoner.h b/src/runtime/c/pgf/reasoner.h
index e314a2dd9..966ba11a5 100644
--- a/src/runtime/c/pgf/reasoner.h
+++ b/src/runtime/c/pgf/reasoner.h
@@ -1,6 +1,8 @@
 #ifndef PGF_REASONER_H_
 #define PGF_REASONER_H_
 
+typedef GuStringMap PgfAbswersMap;
+
 typedef struct PgfReasoner PgfReasoner;
 typedef struct PgfReasonerState PgfReasonerState;
 typedef struct PgfExprState PgfExprState;
@@ -19,4 +21,135 @@ pgf_reasoner_complete(PgfReasoner* rs, PgfExprState* st);
 void
 pgf_reasoner_try_constant(PgfReasoner* rs, PgfExprState* prev, PgfAbsFun* absfun);
 
+typedef struct {
+	PgfFunction code;
+} PgfClosure;
+
+typedef struct {
+	PgfClosure header;
+	PgfClosure* val;
+} PgfIndirection;
+
+typedef struct {
+	PgfLiteral lit;
+	GuBuf* consts;
+	void* enter_stack_ptr;
+} PgfEvalAccum;
+
+struct PgfReasoner {
+	GuPool* pool;
+	GuPool* out_pool;
+	PgfAbstr* abstract;
+	PgfAbswersMap* table;
+	GuBuf* pqueue;
+	GuBuf* exprs;
+	PgfEvalGates* eval_gates; // cached from pgf->abstr->eval_gates
+	GuExn* err;
+	void* enter_stack_ptr;
+	void* tmp;              // for temporary register spills
+	PgfExprEnum en;
+	PgfIndirection cafs[];  // derived from gu_seq_data(pgf->abstr->eval_gates->cafs)
+};
+
+typedef struct PgfEnv PgfEnv;
+
+struct PgfEnv {
+	PgfEnv* next;
+	PgfClosure* closure;
+};
+
+typedef struct {
+	PgfClosure header;
+	PgfEnv*  env;
+	PgfExpr  expr;
+} PgfExprThunk;
+
+typedef struct {
+	PgfClosure header;
+	PgfClosure* con;
+	PgfClosure* args[];
+} PgfValue;
+
+typedef struct {
+	PgfClosure header;
+	int level;
+} PgfValueGen;
+
+typedef struct {
+	PgfClosure header;
+	PgfEnv*  env;
+	PgfMetaId id;
+} PgfValueMeta;
+
+typedef struct {
+	PgfClosure header;
+	PgfLiteral lit;
+} PgfValueLit;
+
+typedef struct {
+	PgfClosure header;
+	PgfLiteral lit;
+	GuBuf* consts;
+} PgfValueSum;
+
+typedef struct {
+	PgfClosure header;
+	PgfClosure* fun;
+	size_t      n_args;
+	PgfClosure* args[];
+} PgfValuePAP;
+
+struct PgfEvalGates {
+	PgfFunction evaluate_expr_thunk;
+	PgfFunction evaluate_indirection;
+	PgfFunction evaluate_value;
+	PgfFunction evaluate_value_lit;
+	PgfFunction evaluate_value_pap;
+	PgfFunction evaluate_value_lambda;
+	PgfFunction evaluate_value_const;
+	PgfFunction evaluate_meta;
+	PgfFunction evaluate_gen;
+	PgfFunction evaluate_sum;
+	PgfFunction evaluate_caf;
+
+	PgfFunction update_closure;
+	PgfFunction update_pap;
+
+	PgfFunction mk_const;
+
+	PgfClosure* (*enter)(PgfReasoner* rs, PgfClosure* closure);
+
+	GuFinalizer fin;
+	GuSeq* cafs;
+};
+
+PgfReasoner*
+pgf_new_reasoner(PgfPGF* pgf, GuExn* err, GuPool* pool, GuPool* out_pool);
+
+PgfClosure*
+pgf_evaluate_expr_thunk(PgfReasoner* rs, PgfExprThunk* thunk);
+
+PgfClosure*
+pgf_evaluate_lambda_application(PgfReasoner* rs, PgfExprThunk* lambda,
+                                                 PgfClosure* arg);
+
+void
+pgf_evaluate_accum_init_int(PgfReasoner* rs, 
+                            PgfEvalAccum* accum, int val);
+
+void
+pgf_evaluate_accum_init_str(PgfReasoner* rs, 
+                            PgfEvalAccum* accum, GuString val);
+                            
+void
+pgf_evaluate_accum_init_flt(PgfReasoner* rs, 
+                            PgfEvalAccum* accum, float val);
+
+void
+pgf_evaluate_accum_add(PgfReasoner* rs, 
+                       PgfEvalAccum* accum, PgfClosure* closure);
+
+PgfClosure*
+pgf_evaluate_accum_done(PgfReasoner* rs, PgfEvalAccum* accum);
+
 #endif
diff --git a/src/runtime/haskell-bind/PGF2.hsc b/src/runtime/haskell-bind/PGF2.hsc
index dc3566627..3d9c44488 100644
--- a/src/runtime/haskell-bind/PGF2.hsc
+++ b/src/runtime/haskell-bind/PGF2.hsc
@@ -113,7 +113,8 @@ generateAll p cat =
     do genPl  <- gu_new_pool
        exprPl <- gu_new_pool
        enum   <- withCString cat $ \cat ->
-                   pgf_generate_all (pgf p) cat genPl
+                   exn <- gu_new_exn genPl
+                   pgf_generate_all (pgf p) cat exn genPl exprPl
        genFPl  <- newForeignPtr gu_pool_finalizer genPl
        exprFPl <- newForeignPtr gu_pool_finalizer exprPl
        fromPgfExprEnum enum genFPl (p,exprFPl)
diff --git a/src/runtime/haskell-bind/PGF2/FFI.hs b/src/runtime/haskell-bind/PGF2/FFI.hs
index 4f7618388..295c1fde9 100644
--- a/src/runtime/haskell-bind/PGF2/FFI.hs
+++ b/src/runtime/haskell-bind/PGF2/FFI.hs
@@ -209,7 +209,7 @@ foreign import ccall "pgf/expr.h pgf_print_expr"
   pgf_print_expr :: PgfExpr -> Ptr PgfPrintContext -> CInt -> Ptr GuOut -> Ptr GuExn -> IO ()
 
 foreign import ccall "pgf/pgf.h pgf_generate_all"
-  pgf_generate_all :: Ptr PgfPGF -> CString -> Ptr GuPool -> IO (Ptr GuEnum)
+  pgf_generate_all :: Ptr PgfPGF -> CString -> Ptr GuExn -> Ptr GuPool -> Ptr GuPool -> IO (Ptr GuEnum)
 
 foreign import ccall "pgf/pgf.h pgf_print"
   pgf_print :: Ptr PgfPGF -> Ptr GuOut -> Ptr GuExn -> IO ()
diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index 5913d1557..a5cd7f644 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -1154,11 +1154,12 @@ JNIEXPORT jobject JNICALL
 Java_org_grammaticalframework_pgf_Generator_generateAll(JNIEnv* env, jclass clazz, jobject jpgf, jstring jstartCat)
 {
 	GuPool* pool = gu_new_pool();
-
+	GuPool* out_pool = gu_new_pool();
     GuString startCat = j2gu_string(env, jstartCat, pool);
+    GuExn* err = gu_exn(pool);
 
 	GuEnum* res =
-		pgf_generate_all(get_ref(env, jpgf), startCat, pool);
+		pgf_generate_all(get_ref(env, jpgf), startCat, err, pool, out_pool);
 	if (res == NULL) {
 		throw_string_exception(env, "org/grammaticalframework/pgf/PGFError", "The generation failed");
 		gu_pool_free(pool);
@@ -1167,7 +1168,7 @@ Java_org_grammaticalframework_pgf_Generator_generateAll(JNIEnv* env, jclass claz
 
 	jclass expiter_class = (*env)->FindClass(env, "org/grammaticalframework/pgf/ExprIterator");
 	jmethodID constrId = (*env)->GetMethodID(env, expiter_class, "<init>", "(Lorg/grammaticalframework/pgf/PGF;JJJ)V");
-	jobject jexpiter = (*env)->NewObject(env, expiter_class, constrId, jpgf, p2l(pool), p2l(pool), p2l(res));
+	jobject jexpiter = (*env)->NewObject(env, expiter_class, constrId, jpgf, p2l(pool), p2l(out_pool), p2l(res));
 
 	return jexpiter;
 }
diff --git a/src/runtime/python/pypgf.c b/src/runtime/python/pypgf.c
index cd4d2d26d..6fea65fd1 100644
--- a/src/runtime/python/pypgf.c
+++ b/src/runtime/python/pypgf.c
@@ -2484,24 +2484,26 @@ PGF_generateAll(PGFObject* self, PyObject *args, PyObject *keywds)
 	pyres->source = (PyObject*) self;
 	Py_INCREF(self);
 
+	GuPool* out_pool = gu_new_pool();
+
+	PyObject* py_pool = PyPool_New(out_pool);
+	pyres->container = PyTuple_Pack(2, pyres->source, py_pool);
+	Py_DECREF(py_pool);
+
 	pyres->pool = gu_new_pool();
 	pyres->max_count = max_count;
 	pyres->counter   = 0;
 	pyres->fetch     = Iter_fetch_expr;
-	pyres->container = (PyObject*) pyres;
 
-	GuPool *tmp_pool = gu_local_pool();
+	GuExn* err = gu_exn(pyres->pool);
 
 	pyres->res =
-		pgf_generate_all(self->pgf, catname, pyres->pool);
+		pgf_generate_all(self->pgf, catname, err, pyres->pool, out_pool);
 	if (pyres->res == NULL) {
 		Py_DECREF(pyres);
-		gu_pool_free(tmp_pool);
 		return NULL;
 	}
 
-	gu_pool_free(tmp_pool);
-
 	return pyres;
 }