1 // Copyright 2022 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 package slog
6 7 import (
8 "fmt"
9 "time"
10 )
11 12 // An Attr is a key-value pair.
13 type Attr struct {
14 Key string
15 Value Value
16 }
17 18 // String returns an Attr for a string value.
19 func String(key, value string) Attr {
20 return Attr{key, StringValue(value)}
21 }
22 23 // Int64 returns an Attr for an int64.
24 func Int64(key string, value int64) Attr {
25 return Attr{key, Int64Value(value)}
26 }
27 28 // Int converts an int to an int64 and returns
29 // an Attr with that value.
30 func Int(key string, value int) Attr {
31 return Int64(key, int64(value))
32 }
33 34 // Uint64 returns an Attr for a uint64.
35 func Uint64(key string, v uint64) Attr {
36 return Attr{key, Uint64Value(v)}
37 }
38 39 // Float64 returns an Attr for a floating-point number.
40 func Float64(key string, v float64) Attr {
41 return Attr{key, Float64Value(v)}
42 }
43 44 // Bool returns an Attr for a bool.
45 func Bool(key string, v bool) Attr {
46 return Attr{key, BoolValue(v)}
47 }
48 49 // Time returns an Attr for a time.Time.
50 // It discards the monotonic portion.
51 func Time(key string, v time.Time) Attr {
52 return Attr{key, TimeValue(v)}
53 }
54 55 // Duration returns an Attr for a time.Duration.
56 func Duration(key string, v time.Duration) Attr {
57 return Attr{key, DurationValue(v)}
58 }
59 60 // Group returns an Attr for a Group Value.
61 // The first argument is the key; the remaining arguments
62 // are converted to Attrs as in [Logger.Log].
63 //
64 // Use Group to collect several key-value pairs under a single
65 // key on a log line, or as the result of LogValue
66 // in order to log a single value as multiple Attrs.
67 func Group(key string, args ...any) Attr {
68 return Attr{key, GroupValue(argsToAttrSlice(args)...)}
69 }
70 71 func argsToAttrSlice(args []any) []Attr {
72 var (
73 attr Attr
74 attrs []Attr
75 )
76 for len(args) > 0 {
77 attr, args = argsToAttr(args)
78 attrs = append(attrs, attr)
79 }
80 return attrs
81 }
82 83 // Any returns an Attr for the supplied value.
84 // See [Value.AnyValue] for how values are treated.
85 func Any(key string, value any) Attr {
86 return Attr{key, AnyValue(value)}
87 }
88 89 // Equal reports whether a and b have equal keys and values.
90 func (a Attr) Equal(b Attr) bool {
91 return a.Key == b.Key && a.Value.Equal(b.Value)
92 }
93 94 func (a Attr) String() string {
95 return fmt.Sprintf("%s=%s", a.Key, a.Value)
96 }
97 98 // isEmpty reports whether a has an empty key and a nil value.
99 // That can be written as Attr{} or Any("", nil).
100 func (a Attr) isEmpty() bool {
101 return a.Key == "" && a.Value.num == 0 && a.Value.any == nil
102 }
103