Say prints is handed to proveNumber, and give shortestDecimals its own const

builtins.go

@@ -16,10 +16,11 @@ import (
 const (
 	maxLen      = 1 << 20
 	maxDecimals = 1024
-	// shortestDecimals prints the fewest digits that read back as the same float64.
-	shortestDecimals = -1
 )
 
+// shortestDecimals prints the fewest digits that read back as the same float64.
+const shortestDecimals = -1
+
 // builtins is the registry of {name(args)} functions. Derivations read the digits
 // emitted so far in the current expansion (place them after their payload);
 // samples read only the rng. A time-based id (uuid v7, ulid) draws its timestamp

format.go

@@ -129,9 +129,9 @@ type builtin struct {
 	// datatypes that text is not; set it where every render reads as a finite number, which
 	// makes the call a calc operand, and leave it nil otherwise.
 	proveNumber func(token string, prints DataType, args []string) proven
-	// prints is the datatype every render's text is, which a typed column holds the call to:
+	// prints is the datatype a call's text is, handed to proveNumber: DataTypeString where it
-	// DataTypeString where it reads as a number but no column should type it, as digits'
+	// reads as a number no column should type, as digits' leading zeros; unset where
-	// leading zeros; unset where proveNumber is nil.
+	// proveNumber is nil.
 	prints DataType
 }