tisp

commit 3be6d85c774f18872bc2482221862c6211e82948
parent e54d2fd87a003d4cab9a1929c92db8ab9c87a3f8
Author: Ed van Bruggen <edvb@uw.edu>
Date:   Sat,  2 Feb 2019 18:35:26 -0800

If only one number is given to /, take its inverse

Diffstat:
test.c
 | 
2
++
tibs/math.c
 | 
11
+++++++++--

2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/test.c b/test.c
@@ -213,6 +213,8 @@ char *tests[][2] = {
 	{ "(/ 8 4)",            "2"                  },
 	{ "(/ 6 2.1)",          "2.85714285714286"   },
 	{ "(/ 4 4/3)",          "3"                  },
+	{ "(/ 5)",              "1/5"                },
+	{ "(/ 4473)",           "1/4473"             },
 	{ "(/ 10.42 5)",        "2.084"              },
 	{ "(/ 1.34e-2 4.3332)", "0.0030924028431644" },
 	{ "(/ 1.04 -15/4)",     "-0.277333333333333" },
diff --git a/tibs/math.c b/tibs/math.c
@@ -116,9 +116,16 @@ static Val
 prim_div(Env env, Val args)
 {
 	Val a, b;
-	tsp_arg_num(args, "/", 2);
+	int len = list_len(args);
+	if (len != 2 && len != 1)
+		tsp_warnf("/: expected 1 or 2 arguments, recieved %d", len);
 	EVAL_CHECK(a, car(args), "/", NUMBER);
-	EVAL_CHECK(b, car(cdr(args)), "/", NUMBER);
+	if (len == 1) {
+		b = a;
+		a = mk_int(1);
+	} else {
+		EVAL_CHECK(b, car(cdr(args)), "/", NUMBER);
+	}
 	if (a->t & DECIMAL || b->t & DECIMAL)
 		return mk_dub((a->v.n.num/a->v.n.den) / (b->v.n.num/b->v.n.den));
 	return (mk_num(a->t, b->t, 1))