Downgrade go minimal version to 1.19

.github/workflows/go.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: '1.21'
+        go-version: '1.19'
 
     - name: Build
       run: go build -v ./...

Readme.md

@@ -6,7 +6,7 @@
 tinyconf - a simple and universal library for parsing configs.
 
 # Installation
-Install via go get. Note that Go 1.18 or newer is required.
+Install via go get. Note that Go 1.19 or newer is required.
 ```sh
 go get github.com/insei/tinyconf@latest
 ```

cmp118/cmp.go

@@ -0,0 +1,52 @@
+package cmp118
+
+// Ordered is a constraint that permits any ordered type: any type
+// that supports the operators < <= >= >.
+// If future releases of Go add new ordered types,
+// this constraint will be modified to include them.
+//
+// Note that floating-point types may contain NaN ("not-a-number") values.
+// An operator such as == or < will always report false when
+// comparing a NaN value with any other value, NaN or not.
+// See the [Compare] function for a consistent way to compare NaN values.
+type Ordered interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 |
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+	~float32 | ~float64 |
+	~string
+}
+
+// Compare returns
+//
+//	-1 if x is less than y,
+//	 0 if x equals y,
+//	+1 if x is greater than y.
+//
+// For floating-point types, a NaN is considered less than any non-NaN,
+// a NaN is considered equal to a NaN, and -0.0 is equal to 0.0.
+func Compare[T Ordered](x, y T) int {
+	xNaN := isNaN(x)
+	yNaN := isNaN(y)
+	if xNaN {
+		if yNaN {
+			return 0
+		}
+		return -1
+	}
+	if yNaN {
+		return +1
+	}
+	if x < y {
+		return -1
+	}
+	if x > y {
+		return +1
+	}
+	return 0
+}
+
+// isNaN reports whether x is a NaN without requiring the math package.
+// This will always return false if T is not floating-point.
+func isNaN[T Ordered](x T) bool {
+	return x != x
+}

drivers/env/env.go

@@ -2,17 +2,18 @@ package env
 
 import (
 	"bufio"
-	"cmp"
 	"fmt"
 	"os"
 	"path"
 	"reflect"
-	"slices"
 	"strings"
 
+	"github.com/insei/tinyconf"
+	"github.com/insei/tinyconf/cmp118"
+	"github.com/insei/tinyconf/slices118"
+
 	"github.com/insei/cast"
 	"github.com/insei/fmap/v3"
-	"github.com/insei/tinyconf"
 )
 
 type envDriver struct {
@@ -73,7 +74,7 @@ func (d envDriver) getUniqueFields(registers []*tinyconf.Registered) []field {
 				tag:   tag,
 			}
 
-			if slices.ContainsFunc(fields, func(item field) bool {
+			if slices118.ContainsFunc(fields, func(item field) bool {
 				return item.tag.Get(d.name) == member.tag.Get(d.name)
 			}) {
 				continue
@@ -98,17 +99,17 @@ func (d envDriver) getRootMap(fields []field) map[int]map[string]string {
 func (d envDriver) GenDoc(registers ...*tinyconf.Registered) string {
 	uniqueFields := d.getUniqueFields(registers)
 
-	sortedFields := slices.Clone(uniqueFields)
-	slices.SortStableFunc(sortedFields, func(i, j field) int {
-		return cmp.Compare(j.depth, i.depth)
+	sortedFields := slices118.Clone(uniqueFields)
+	slices118.SortStableFunc(sortedFields, func(i, j field) int {
+		return cmp118.Compare(j.depth, i.depth)
 	})
 
 	roots := d.getRootMap(sortedFields)
 	marks := make([]string, 0)
 
 	var doc string
 	for _, field := range uniqueFields {
-		if slices.Contains(marks, field.path) {
+		if slices118.Contains(marks, field.path) {
 			continue
 		}
 		marks = append(marks, field.path)

drivers/yaml/yaml.go

@@ -1,15 +1,16 @@
 package yaml
 
 import (
-	"cmp"
 	"fmt"
 	"reflect"
-	"slices"
 	"strings"
 
 	"github.com/insei/cast"
 	"github.com/insei/fmap/v3"
+
 	"github.com/insei/tinyconf"
+	"github.com/insei/tinyconf/cmp118"
+	"github.com/insei/tinyconf/slices118"
 )
 
 type yamlDriver struct {
@@ -116,7 +117,7 @@ func (d *yamlDriver) getUniqueFields(registers []*tinyconf.Registered) []field {
 				tag:   tag,
 			}
 
-			if slices.ContainsFunc(fields, func(item field) bool {
+			if slices118.ContainsFunc(fields, func(item field) bool {
 				matchPath := item.path == member.path
 				matchTagDriver := tagDriver == item.tag.Get(d.name)
 				return matchPath && matchTagDriver
@@ -151,9 +152,9 @@ func (d *yamlDriver) getRootMap(fields []field) map[string]string {
 func (d *yamlDriver) GenDoc(registers ...*tinyconf.Registered) string {
 	uniqueFields := d.getUniqueFields(registers)
 
-	sortedFields := slices.Clone(uniqueFields)
-	slices.SortStableFunc(sortedFields, func(i, j field) int {
-		return cmp.Compare(i.path, j.path)
+	sortedFields := slices118.Clone(uniqueFields)
+	slices118.SortStableFunc(sortedFields, func(i, j field) int {
+		return cmp118.Compare(i.path, j.path)
 	})
 
 	roots := d.getRootMap(sortedFields)

go.mod

@@ -1,10 +1,10 @@
 module github.com/insei/tinyconf
 
-go 1.21
+go 1.19
 
 require (
 	github.com/insei/cast v1.1.1
-	github.com/insei/fmap/v3 v3.0.0
+	github.com/insei/fmap/v3 v3.1.2
 	github.com/stretchr/testify v1.9.0
 	go.uber.org/zap v1.27.0
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -4,14 +4,13 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/insei/cast v1.1.1 h1:Elrnc3yo5FvaN8B6KWP/+UWblgKG8uj0/UbE/olcLYM=
 github.com/insei/cast v1.1.1/go.mod h1:WyueAs28LJPpteJTcUZbkt3eLffnNczOR7B4ODQ8lrE=
-github.com/insei/fmap/v3 v3.0.0 h1:BpRsFgQ2nt5tl/8tzp6y+MWIAJhqCTeKBHC56L/Um30=
-github.com/insei/fmap/v3 v3.0.0/go.mod h1:Kk0gs7nKb4E/JycKJFnrsX5hlyBBe0yetGKFCJG0vzk=
+github.com/insei/fmap/v3 v3.1.2 h1:ZBr+WiZpIxFNeMo2X4QOST4AFl0sGAkG+EO08Ved3bY=
+github.com/insei/fmap/v3 v3.1.2/go.mod h1:Kk0gs7nKb4E/JycKJFnrsX5hlyBBe0yetGKFCJG0vzk=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
-go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
 go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
 go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=

slices118/slices.go

@@ -0,0 +1,48 @@
+// Package slices118 defines various functions useful with slices118 of any type.
+package slices118
+
+// Index returns the index of the first occurrence of v in s,
+// or -1 if not present.
+func Index[S ~[]E, E comparable](s S, v E) int {
+	for i := range s {
+		if v == s[i] {
+			return i
+		}
+	}
+	return -1
+}
+
+// IndexFunc returns the first index i satisfying f(s[i]),
+// or -1 if none do.
+func IndexFunc[S ~[]E, E any](s S, f func(E) bool) int {
+	for i := range s {
+		if f(s[i]) {
+			return i
+		}
+	}
+	return -1
+}
+
+// Contains reports whether v is present in s.
+func Contains[S ~[]E, E comparable](s S, v E) bool {
+	return Index(s, v) >= 0
+}
+
+// ContainsFunc reports whether at least one
+// element e of s satisfies f(e).
+func ContainsFunc[S ~[]E, E any](s S, f func(E) bool) bool {
+	return IndexFunc(s, f) >= 0
+}
+
+// Clone returns a copy of the slice.
+// The elements are copied using assignment, so this is a shallow clone.
+// The result may have additional unused capacity.
+func Clone[S ~[]E, E any](s S) S {
+	// Preserve nilness in case it matters.
+	if s == nil {
+		return nil
+	}
+	// Avoid s[:0:0] as it leads to unwanted liveness when cloning a
+	// zero-length slice of a large array; see https://go.dev/issue/68488.
+	return append(S{}, s...)
+}