From 5b5f1056df87e9dce7822179cf49b2b4579ae306 Mon Sep 17 00:00:00 2001
From: Ev Dolzhenko <dolzenko@gmail.com>
Date: Mon, 7 Jul 2025 17:12:06 +0300
Subject: [PATCH] Add abs and absf math functions

---
 docs/math.md    | 10 ++++++++++
 docs/mathf.md   | 10 ++++++++++
 functions.go    |  2 ++
 numeric.go      | 15 ++++++++++++++-
 numeric_test.go | 14 ++++++++++++++
 5 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/docs/math.md b/docs/math.md
index b08d0a2f..b15f186c 100644
--- a/docs/math.md
+++ b/docs/math.md
@@ -34,6 +34,16 @@ Multiply with `mul`. Accepts two or more inputs.
 mul 1 2 3
 ```
 
+## abs
+
+Return the absolute value of an integer.
+
+This will return `3`:
+
+```
+abs -3
+```
+
 ## max
 
 Return the largest of a series of integers:
diff --git a/docs/mathf.md b/docs/mathf.md
index 759c8525..0fa4a2e9 100644
--- a/docs/mathf.md
+++ b/docs/mathf.md
@@ -65,3 +65,13 @@ This will return `1.5`:
 ```
 minf 1.5 2 3
 ```
+
+## absf
+
+Return the absolute value of a float.
+
+This will return `3.14`:
+
+```
+absf -3.14
+```
diff --git a/functions.go b/functions.go
index cda47d26..6e621b59 100644
--- a/functions.go
+++ b/functions.go
@@ -229,6 +229,8 @@ var genericMap = map[string]interface{}{
 	"min":     min,
 	"maxf":    maxf,
 	"minf":    minf,
+	"abs":     abs,
+	"absf":    absf,
 	"ceil":    ceil,
 	"floor":   floor,
 	"round":   round,
diff --git a/numeric.go b/numeric.go
index f68e4182..ab6a434a 100644
--- a/numeric.go
+++ b/numeric.go
@@ -6,8 +6,8 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/spf13/cast"
 	"github.com/shopspring/decimal"
+	"github.com/spf13/cast"
 )
 
 // toFloat64 converts 64-bit floats
@@ -64,6 +64,19 @@ func minf(a interface{}, i ...interface{}) float64 {
 	return aa
 }
 
+func abs(a interface{}) int64 {
+	aa := toInt64(a)
+	if aa < 0 {
+		return -aa
+	}
+	return aa
+}
+
+func absf(a interface{}) float64 {
+	aa := toFloat64(a)
+	return math.Abs(aa)
+}
+
 func until(count int) []int {
 	step := 1
 	if count < 0 {
diff --git a/numeric_test.go b/numeric_test.go
index 1252cd73..e54afb4f 100644
--- a/numeric_test.go
+++ b/numeric_test.go
@@ -277,6 +277,20 @@ func TestSubf(t *testing.T) {
 	}
 }
 
+func TestAbs(t *testing.T) {
+	tpl := `{{ abs -3 }}`
+	if err := runt(tpl, `3`); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestAbsf(t *testing.T) {
+	tpl := `{{ absf -3.4 }}`
+	if err := runt(tpl, `3.4`); err != nil {
+		t.Error(err)
+	}
+}
+
 func TestCeil(t *testing.T) {
 	assert.Equal(t, 123.0, ceil(123))
 	assert.Equal(t, 123.0, ceil("123"))