1 files changed, 102 insertions, 0 deletions
diff --git a/src/log/slog/attr.go b/src/log/slog/attr.go
new file mode 100644
index 0000000..90e343b
--- /dev/null
+++ b/src/log/slog/attr.go
@@ -0,0 +1,102 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package slog
+
+import (
+	"fmt"
+	"time"
+)
+
+// An Attr is a key-value pair.
+type Attr struct {
+	Key   string
+	Value Value
+}
+
+// String returns an Attr for a string value.
+func String(key, value string) Attr {
+	return Attr{key, StringValue(value)}
+}
+
+// Int64 returns an Attr for an int64.
+func Int64(key string, value int64) Attr {
+	return Attr{key, Int64Value(value)}
+}
+
+// Int converts an int to an int64 and returns
+// an Attr with that value.
+func Int(key string, value int) Attr {
+	return Int64(key, int64(value))
+}
+
+// Uint64 returns an Attr for a uint64.
+func Uint64(key string, v uint64) Attr {
+	return Attr{key, Uint64Value(v)}
+}
+
+// Float64 returns an Attr for a floating-point number.
+func Float64(key string, v float64) Attr {
+	return Attr{key, Float64Value(v)}
+}
+
+// Bool returns an Attr for a bool.
+func Bool(key string, v bool) Attr {
+	return Attr{key, BoolValue(v)}
+}
+
+// Time returns an Attr for a time.Time.
+// It discards the monotonic portion.
+func Time(key string, v time.Time) Attr {
+	return Attr{key, TimeValue(v)}
+}
+
+// Duration returns an Attr for a time.Duration.
+func Duration(key string, v time.Duration) Attr {
+	return Attr{key, DurationValue(v)}
+}
+
+// Group returns an Attr for a Group Value.
+// The first argument is the key; the remaining arguments
+// are converted to Attrs as in [Logger.Log].
+//
+// Use Group to collect several key-value pairs under a single
+// key on a log line, or as the result of LogValue
+// in order to log a single value as multiple Attrs.
+func Group(key string, args ...any) Attr {
+	return Attr{key, GroupValue(argsToAttrSlice(args)...)}
+}
+
+func argsToAttrSlice(args []any) []Attr {
+	var (
+		attr  Attr
+		attrs []Attr
+	)
+	for len(args) > 0 {
+		attr, args = argsToAttr(args)
+		attrs = append(attrs, attr)
+	}
+	return attrs
+}
+
+// Any returns an Attr for the supplied value.
+// See [AnyValue] for how values are treated.
+func Any(key string, value any) Attr {
+	return Attr{key, AnyValue(value)}
+}
+
+// Equal reports whether a and b have equal keys and values.
+func (a Attr) Equal(b Attr) bool {
+	return a.Key == b.Key && a.Value.Equal(b.Value)
+}
+
+func (a Attr) String() string {
+	return fmt.Sprintf("%s=%s", a.Key, a.Value)
+}
+
+// isEmpty reports whether a has an empty key and a nil value.
+// That can be written as Attr{} or Any("", nil).
+func (a Attr) isEmpty() bool {
+	return a.Key == "" && a.Value.num == 0 && a.Value.any == nil
+}