From 8ca887aa7d6e75a9aafddb9a793a1272306d4e05 Mon Sep 17 00:00:00 2001
From: Lilleman auf Larv <lilleman@larvit.se>
Date: Tue, 15 Sep 2026 14:39:25 +0200
Subject: [PATCH] Name digits among an operand's spellings, and document number
 by what its text is

---
 template.go | 2 +-
 value.go    | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/template.go b/template.go
index 0b9e76b..1e5d3e6 100644
--- a/template.go
+++ b/template.go
@@ -73,7 +73,7 @@ type builtin struct {
 	// for a builtin that reads none.
 	operands func(args []string) []string
 	// number bounds the number a call prints and names the datatype its text is; nil
-	// for a builtin that prints text.
+	// for a builtin whose text is no number.
 	number func(args []string) (proven, DataType)
 }
 
diff --git a/value.go b/value.go
index 56c3d93..5d580b5 100644
--- a/value.go
+++ b/value.go
@@ -92,7 +92,9 @@ func (p *valueProof) template(t *template) proven {
 	case t.fixed:
 		return literalValue(t.lit)
 	case len(t.ops) != 1:
-		return unproven(fmt.Sprintf("%q is not one value; write one literal or one {int()}, {float()}, {seq()} or {calc()}, or read one", t.format))
+		v := unproven(notOneValue(t.format, "{int()}, {float()}, {seq()} or {calc()}"))
+		v.notNumber = notOneValue(t.format, "{int()}, {float()}, {seq()}, {digits()} or {calc()}")
+		return v
 	}
 	body := t.format[1 : len(t.format)-1]
 	name, args, isFunc := funcCall(body)
@@ -227,6 +229,10 @@ func printing(token string, prints DataType, v proven) proven {
 	return v
 }
 
+func notOneValue(format, calls string) string {
+	return fmt.Sprintf("%q is not one value; write one literal or one %s, or read one", format, calls)
+}
+
 // unproven is a render no datatype and no calc can take, for why.
 func unproven(why string) proven {
 	v := proven{notNumber: why}