diff --git a/b2/CURR b/b2/CURR
new file mode 100644
index 0000000..c43151a
--- /dev/null
+++ b/b2/CURR
@@ -0,0 +1,2 @@
+EUR  USD 1.3214 GBP 1.62542
+GBP  USD 0.615219
diff --git a/b2/Makefile b/b2/Makefile
index d578867..e3db6b7 100644
--- a/b2/Makefile
+++ b/b2/Makefile
@@ -83,4 +83,4 @@ spotless:	clean
 # ----- Experiments -----------------------------------------------------------
 
 try:
-	$(VALGRIND) ./boom HIERARCHY -c CHAR -i INV
+	$(VALGRIND) ./boom HIERARCHY -c CHAR -x CURR -i INV
diff --git a/b2/boom.c b/b2/boom.c
index ad8c3bf..307ca4e 100644
--- a/b2/boom.c
+++ b/b2/boom.c
@@ -42,6 +42,7 @@ static void usage(const char *name)
 "  file types:\n"
 "  -c  characteristics\n"
 "  -i  inventory\n"
+"  -x  currency exchange\n"
     , name);
 	exit(1);
 }
@@ -58,6 +59,8 @@ int main(int argc, char **argv)
 				parse = parse_characteristics;
 			else if (!strcmp(argv[i], "-i"))
 				parse = parse_inventory;
+			else if (!strcmp(argv[i], "-x"))
+				parse = parse_currencies;
 			else
 				usage(*argv);
 		} else {
diff --git a/b2/db.c b/b2/db.c
index 12e508c..432554a 100644
--- a/b2/db.c
+++ b/b2/db.c
@@ -173,7 +173,7 @@ static void dump_stock(FILE *file, const struct stock *s)
 	const struct price *p;
 
 	fprintf(file, "    %s  %d %d  %s %g",
-	    s->cat, s->avail, s->package, "???", s->add);
+	    s->cat, s->avail, s->package, s->curr->name, s->add);
 	for (p = s->price; p; p = p->next)
 		fprintf(file,  " %d %g", p->qty, p->value);
 	fprintf(file, "\n");
@@ -196,3 +196,64 @@ void part_dump(FILE *file, const struct part *part)
 	if (part->stock)
 		dump_stock(file, part->stock);
 }
+
+
+/* ----- Currencies -------------------------------------------------------- */
+
+
+static struct currency *currencies = NULL;
+
+
+const struct currency *currency_lookup(const char *name)
+{
+	const struct currency *c;
+
+	for (c = currencies; c; c = c->next)
+		if (c->name == name)
+			break;
+	return c;
+}
+
+
+double currency_convert(const struct currency *from, const struct currency *to,
+    double value)
+{
+	const struct exchange *ex;
+
+	for (ex = from->exchange; ex; ex = ex->next)
+		if (ex->dst == to)
+			return ex->rate*value;
+	fprintf(stderr, "cannot convert %s to %s\n", from->name, to->name);
+	exit(1);
+}
+
+
+struct currency *currency_add(const char *name)
+{
+	struct currency **c;
+
+	for (c = &currencies; *c; c = &(*c)->next)
+		if ((*c)->name == name)
+			return *c;
+	*c = alloc_type(struct currency);
+	(*c)->name = name;
+	(*c)->exchange = NULL;
+	(*c)->next = NULL;
+	return *c;
+}
+
+
+void currency_exchange(struct currency *from, const struct currency *to,
+    double rate)
+{
+	struct exchange **ex;
+
+	for (ex = &from->exchange; *ex; ex = &(*ex)->next)
+		if ((*ex)->dst == to)
+			yyerrorf("exchange %s -> %s is already defined",
+			    from->name, to->name);
+	*ex = alloc_type(struct exchange);
+	(*ex)->dst = to;
+	(*ex)->rate = rate;
+	(*ex)->next = NULL;
+}
diff --git a/b2/db.h b/b2/db.h
index d5e92e4..85fb505 100644
--- a/b2/db.h
+++ b/b2/db.h
@@ -18,7 +18,7 @@
 
 struct exchange {
 	const struct currency *dst;
-	double factor;
+	double rate;	/* dst = rate*src */
 	struct exchange *next;
 };
 
@@ -98,4 +98,11 @@ void part_finalize(struct part *part, const struct action *act);
 void part_add_stock(struct part *part, struct stock *stock);
 void part_dump(FILE *file, const struct part *part);
 
+const struct currency *currency_lookup(const char *name);
+double currency_convert(const struct currency *from, const struct currency *to,
+    double value);
+struct currency *currency_add(const char *name);
+void currency_exchange(struct currency *from, const struct currency *to,
+    double rate);
+
 #endif /* !DB_H */
diff --git a/b2/lang.h b/b2/lang.h
index ae61fca..6239d6b 100644
--- a/b2/lang.h
+++ b/b2/lang.h
@@ -16,6 +16,7 @@
 void parse_hierarchy(void);
 void parse_characteristics(void);
 void parse_inventory(void);
+void parse_currencies(void);
 
 void yywarnf(const char *fmt, ...);
 void yyerrorf(const char *fmt, ...);
diff --git a/b2/lang.l b/b2/lang.l
index ac27462..f74ee70 100644
--- a/b2/lang.l
+++ b/b2/lang.l
@@ -53,6 +53,14 @@ void parse_inventory(void)
 	yyparse();
 }
 
+void parse_currencies(void)
+{
+	start_token = START_EXCHANGE;
+	expose_nl = 1;
+	lineno = 1;
+	yyparse();
+}
+
 %}
 
 
diff --git a/b2/lang.y b/b2/lang.y
index 04b0bd9..708b8ff 100644
--- a/b2/lang.y
+++ b/b2/lang.y
@@ -24,6 +24,8 @@
 
 
 static struct action hierarchy;
+static struct currency *curr;
+
 
 static struct field_stack {
 	const struct field *field;
@@ -82,6 +84,7 @@ static const struct field *top_field(void)
 
 
 %token			START_HIERARCHY START_CHAR START_INVENTORY
+%token			START_EXCHANGE
 %token			TOK_LE TOK_GE TOK_NL
 %token	<s>		WORD
 
@@ -106,6 +109,7 @@ all:
 	START_HIERARCHY hierarchy
 	| START_CHAR characteristics
 	| START_INVENTORY inventory
+	| START_EXCHANGE exchange
 	;
 
 
@@ -432,7 +436,9 @@ stock:
 			$$->cat = $1;
 			$$->avail = $2;
 			$$->package = $3;
-			$$->curr = NULL; /* @@@ later -- currency($4); */
+			$$->curr = currency_lookup($4);
+			if (!$$->curr)
+				yyerrorf("unknown currency %s", $4);
 			$$->add = $5;
 			$$->price = $6;
 		}
@@ -481,3 +487,36 @@ float:
 				yyerrorf("\"%s\" is not a number", $1);
 		}
 	;
+
+
+/* ----- Currency exchange ------------------------------------------------- */
+
+
+exchange:
+	| TOK_NL
+	| currency exchange
+	;
+
+currency:
+	WORD
+		{
+			curr = currency_add($1);
+		}
+	    rates TOK_NL
+	;
+
+rates:
+	| rate rates
+	;
+
+rate:
+	WORD float
+		{
+			const struct currency *to;
+
+			/* add and not lookup, since we just introduce the
+			   currency here */
+			to = currency_add($1);
+			currency_exchange(curr, to, $2);
+		}
+	;