diff --git a/go/src/miller/dsl/cst/function_manager.go b/go/src/miller/dsl/cst/function_manager.go
index 16a28d6cf..d903cd0c1 100644
--- a/go/src/miller/dsl/cst/function_manager.go
+++ b/go/src/miller/dsl/cst/function_manager.go
@@ -341,6 +341,10 @@ var BUILTIN_FUNCTION_LOOKUP_TABLE = []FunctionInfo{
 		name:        "?:",
 		ternaryFunc: TernaryShortCircuitPlaceholder,
 	},
+	{
+		name:        "ssub",
+		ternaryFunc: types.MlrvalSsub,
+	},
 
 	// Variadic built-in functions
 	{
diff --git a/go/src/miller/types/mlrval_accessors.go b/go/src/miller/types/mlrval_accessors.go
index 8c9b833de..c1334a4f7 100644
--- a/go/src/miller/types/mlrval_accessors.go
+++ b/go/src/miller/types/mlrval_accessors.go
@@ -14,6 +14,10 @@ func GetTypeName(mvtype MVType) string {
 }
 
 // ----------------------------------------------------------------
+func (this *Mlrval) IsErrorOrAbsent() bool {
+	return this.mvtype == MT_ERROR || this.mvtype == MT_ABSENT
+}
+
 func (this *Mlrval) IsError() bool {
 	return this.mvtype == MT_ERROR
 }
@@ -34,6 +38,10 @@ func (this *Mlrval) IsString() bool {
 	return this.mvtype == MT_STRING
 }
 
+func (this *Mlrval) IsStringOrVoid() bool {
+	return this.mvtype == MT_STRING || this.mvtype == MT_VOID
+}
+
 func (this *Mlrval) IsInt() bool {
 	return this.mvtype == MT_INT
 }
diff --git a/go/src/miller/types/mlrval_functions.go b/go/src/miller/types/mlrval_functions.go
index 8a991afa4..b9c9eb06d 100644
--- a/go/src/miller/types/mlrval_functions.go
+++ b/go/src/miller/types/mlrval_functions.go
@@ -2,6 +2,7 @@ package types
 
 import (
 	"math"
+	"strings"
 	"time"
 
 	"miller/lib"
@@ -1704,3 +1705,28 @@ func NumericAscendingComparator(ma *Mlrval, mb *Mlrval) int {
 func NumericDescendingComparator(ma *Mlrval, mb *Mlrval) int {
 	return NumericAscendingComparator(mb, ma)
 }
+
+// ================================================================
+func MlrvalSsub(ma, mb, mc *Mlrval) Mlrval {
+	if ma.IsErrorOrAbsent() {
+		return *ma
+	}
+	if mb.IsErrorOrAbsent() {
+		return *mb
+	}
+	if mb.IsErrorOrAbsent() {
+		return *mc
+	}
+	if !ma.IsStringOrVoid() {
+		return MlrvalFromError()
+	}
+	if !mb.IsStringOrVoid() {
+		return MlrvalFromError()
+	}
+	if !mc.IsStringOrVoid() {
+		return MlrvalFromError()
+	}
+	return MlrvalFromString(
+		strings.Replace(ma.printrep, mb.printrep, mc.printrep, 1),
+	)
+}
diff --git a/go/u/try-cst b/go/u/try-cst
index 279aa82b3..67f2b240d 100755
--- a/go/u/try-cst
+++ b/go/u/try-cst
@@ -230,3 +230,5 @@ echo; run_mlr --from u/s.dkvp put 'if (NR == 1) { $z = 100 } else { $z = 900 }'
 echo; run_mlr --from u/s.dkvp put 'if (NR == 1) { $z = 100 } elif (NR == 2) { $z = 200 }'
 echo; run_mlr --from u/s.dkvp put 'if (NR == 1) { $z = 100 } elif (NR == 2) { $z = 200 } else { $z = 900 }'
 echo; run_mlr --from u/s.dkvp put 'if (NR == 1) { $z = 100 } elif (NR == 2) { $z = 200 } elif (NR == 3) { $z = 300 } else { $z = 900 }'
+
+echo x=eeee | run_mlr put '$y=ssub($x, "e", "X")'
diff --git a/go/u/try-cst.out b/go/u/try-cst.out
index 65d5d7510..5630ea15a 100644
--- a/go/u/try-cst.out
+++ b/go/u/try-cst.out
@@ -2416,3 +2416,7 @@ a=pan,b=pan,i=1,x=0.3467901443380824,y=0.7268028627434533,z=100
 a=eks,b=pan,i=2,x=0.7586799647899636,y=0.5221511083334797,z=200
 a=wye,b=wye,i=3,x=0.20460330576630303,y=0.33831852551664776,z=300
 a=eks,b=wye,i=4,x=0.38139939387114097,y=0.13418874328430463,z=900
+
+----------------------------------------------------------------
+mlr put $y=ssub($x, "e", "X")
+x=eeee,y=Xeee
diff --git a/go/u/try-verbs.out b/go/u/try-verbs.out
index 22babe586..a5b4e9e9c 100644
--- a/go/u/try-verbs.out
+++ b/go/u/try-verbs.out
@@ -352,3 +352,22 @@ mlr --json --from u/needs-sorting.json sort-within-records
   "b": 2,
   "c": 3
 }
+
+----------------------------------------------------------------
+mlr --json --from u/needs-regularize.json regularize
+{
+  "b": 2,
+  "c": 3,
+  "a": 1
+}
+{
+  "b": 2,
+  "c": 3,
+  "a": 1
+}
+{
+  "d": 4,
+  "a": 1,
+  "b": 2,
+  "c": 3
+}