The Scandalous Story of the Dreadful Code Written by the Best of Us

There are overlooked corners of our codebases. Ignored, unloved. Unimportant. Or so we thought.

What once was inconsequential has—somehow—grown into ghastly mess.

This talk tells the story of one such mess, and the taming of it.

Transcript

1. The Scandalous Story of the Dreadful Code Written by the Best of Us Katrina Owen ! GitHub
2. I never get the notifications when we run out of stuff.
3. resource depleted
4. Alice reports that we are out of ammo. TEXT
5. Alice says we're running low on ammo. HTML
6. copy | paste
7. package notify
8. it's totally fine
9. // TODO: add tests
10. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... } func Dispatch(s string, p *game.Person) { // ... horrible things... } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... }
11. Did the message say the right thing?
12. Did the right people get the message?
13. \o/
14. The No-op No-op No-op Interface Maneuver
15. one undo
16. no-op #1
17. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... } func Dispatch(s string, p *game.Person) { // ... horrible things... } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... } no-op #1
18. package comms type Signal struct{} no-op #1
19. package comms type Signal struct{} func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { } func (*Signal) Dispatch(s string, p *game.Person) { } func (*Signal) Register(e game.Event, p *game.Person) { } no-op #1
20. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... } func Dispatch(s string, p *game.Person) { // ... horrible things... } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... } no-op #1
21. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... } func Dispatch(s string, p *game.Person) { // ... horrible things... } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... } no-op #1
22. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) } func Dispatch(s string, p *game.Person) { // ... horrible things... Sig.Dispatch(s, p) } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... Sig.Register(e, p) } no-op #1
23. package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) } func Dispatch(s string, p *game.Person) { // ... horrible things... Sig.Dispatch(s, p) } func Register(e game.Event, p *game.Person) { // ... kind of confusing stuff... Sig.Register(e, p) } no-op #1
24. package comms var Sig *Signal func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { } func (*Signal) Dispatch(s string, p *game.Person) { } func (*Signal) Register(e game.Event, p *game.Person) { } no-op #1
25. package comms var Sig *Signal func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { } func (*Signal) Dispatch(s string, p *game.Person) { } func (*Signal) Register(e game.Event, p *game.Person) { } no-op #1
26. package comms var Sig *Signal func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { } func (*Signal) Dispatch(s string, p *game.Person) { } func (*Signal) Register(e game.Event, p *game.Person) { } no-op #1
27. no-op #1
28. no-op #2
29. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) }
30. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) }
31. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) }
32. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) } func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { }
33. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... Sig.Broadcast(s, f, c) } func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { }
34. no-op #2 package comms func Broadcast(s string, f game.Freq, c Crypto) { Sig.Broadcast(s, f, c) } func (*Signal) Broadcast(s string, f game.Freq, c Crypto) { // ... a mountain of complexity... }
35. no-op #2
36. no-op #3
37. no-op #3 package notify func ResourceDepleted(r game.Resource, p *game.Person) { // ... comms.Broadcast(...) // ... }
38. no-op #3 package notify func ResourceDepleted(com *comms.Signal, r game.Resource, p *game.Person ) { // ... comms.Broadcast(...) // ... }
39. package api notify.ResourceDepleted(comms.Sig, resource, person) no-op #3
40. no-op #3 package notify func ResourceDepleted(com *comms.Signal, r game.Resource, p *game.Person ) { // ... comms.Broadcast(...) // ... }
41. package notify func ResourceDepleted(com *comms.Signal, r game.Resource, p *game.Person ) { // ... com.Broadcast(...) // ... } no-op #3
42. package comms func Broadcast(s string, f game.Freq, c Crypto) { Sig.Broadcast(s, f, c) } func Dispatch(s string, p *game.Person) { Sig.Dispatch(s, p) } func Register(e game.Event, p *game.Person) { Sig.Register(e, p) } no-op #3
43. no-op #3 package comms
44. no-op #3
45. interface
46. package comms type Transmitter interface { Broadcast(string, game.Freq, Crypto) Dispatch(string, *game.Person) Register(game.Event, *game.Person) } interface
47. interface package notify func ResourceDepleted(com *comms.Signal, r game.Resource, p *game.Person ) { // ... com.Broadcast(...) // ... }
48. interface package notify func ResourceDepleted(com *comms.Signal, r game.Resource, p *game.Person ) { // ... com.Broadcast(...) // ... }
49. interface package notify func ResourceDepleted(com comms.Transmitter, r game.Resource, p *game.Person ) { // ... com.Broadcast(...) // ... }
50. interface package notify type fakeTransmitter struct { broadcasts []fakeBroadcast dispatches []fakeDispatch events []fakeEvent }
51. package notify type fakeTransmitter struct { broadcasts []fakeBroadcast dispatches []fakeDispatch events []fakeEvent } func (*fakeTransmitter) Broadcast(...) { } func (*fakeTransmitter) Dispatch(...) { } func (*fakeTransmitter) Register(...) { } interface
52. no-op no-op no-op interface maneuver
53. clean code
54. The Flocking Rules
55. find the things that are most alike rule #1
56. select the smallest difference between them rule #2
57. make the smallest change that will remove that difference rule #3
58. the flocking rules
59. resource found
60. text vs html
61. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, )
62. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, )
63. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, )
64. html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a>"+ " at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
65. html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a>"+ " at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
66. html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a>"+ " at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
67. find the things that are most alike rule #1
68. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
69. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
70. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
71. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
72. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
73. select the smallest difference between them rule #2
74. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
75. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
76. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
77. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%s&lon=%s'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
78. make the smallest change that will remove that difference rule #3
79. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%s&lon=%s'>%s</a>.", v4, v5, v6, v7, v8, v9, v10, v11, )
80. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "%s discovered %s at %s.", anchor1, anchor2, anchor3, )
81. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "%s discovered %s at %s.", anchor1, anchor2, anchor3, )
82. anchor1 := fmt.Sprintf( "<a href='/people/%s'>%s</a>", p.Handle, template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='/tribes/%s/resources/%s'>%s</a>", r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='/maps?lat=%f&lon=%f'>%s</a>", loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
83. text := fmt.Sprintf( "%s discovered %s at %s.", v1, v2, v3, ) html := fmt.Sprintf( "%s discovered %s at %s.", anchor1, anchor2, anchor3, )
84. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, v1, v2, v3, ) html := fmt.Sprintf( msg, anchor1, anchor2, anchor3, )
85. find the things that are most alike rule #1
86. anchor1 := fmt.Sprintf( "<a href='/people/%s'>%s</a>", p.Handle, template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='/tribes/%s/resources/%s'>%s</a>", r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='/maps?lat=%f&lon=%f'>%s</a>", loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
87. select the smallest difference between them rule #2
88. anchor1 := fmt.Sprintf( "<a href='/people/%s'>%s</a>", p.Handle, template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='/tribes/%s/resources/%s'>%s</a>", r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='/maps?lat=%f&lon=%f'>%s</a>", loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
89. anchor1 := fmt.Sprintf( "<a href='/people/%s'>%s</a>", p.Handle, template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='/tribes/%s/resources/%s'>%s</a>", r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='/maps?lat=%f&lon=%f'>%s</a>", loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
90. make the smallest change that will remove that difference rule #3
91. anchor1 := fmt.Sprintf( "<a href='/people/%s'>%s</a>", p.Handle, template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='/tribes/%s/resources/%s'>%s</a>", r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='/maps?lat=%f&lon=%f'>%s</a>", loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
92. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
93. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
94. find the things that are most alike rule #1
95. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
96. select the smallest difference between them rule #2
97. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.Name), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.Name), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
98. make the smallest change that will remove that difference rule #3
99. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.String()), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
100. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.String()), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
101. find the things that are most alike rule #1
102. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.String()), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
103. select the smallest difference between them rule #2
104. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.String()), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
105. make the smallest change that will remove that difference rule #3
106. anchor1 := fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) anchor2 := fmt.Sprintf( "<a href='%s'>%s</a>", r.URL(), template.HTMLEscapeString(r.String()), ) anchor3 := fmt.Sprintf( "<a href='%s'>%s</a>", loc.URL(), template.HTMLEscapeString(loc.String()), )
107. type linker interface { String() string URL() string }
108. type linker interface { String() string URL() string }
109. func link(l linker) string { fmt.Sprintf( "<a href='%s'>%s</a>", p.URL(), template.HTMLEscapeString(p.String()), ) }
110. func link(l linker) string { return fmt.Sprintf( "<a href='%s'>%s</a>", l.URL(), template.HTMLEscapeString(l.String()), ) }
111. func link(l linker) string { return fmt.Sprintf( "<a href='%s'>%s</a>", l.URL(), template.HTMLEscapeString(l.String()), ) }
112. find the things that are most alike rule #1
113. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p.Name, r.Name, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
114. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p.Name, r.Name, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
115. select the smallest difference between them rule #2
116. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p.Name, r.Name, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
117. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p.Name, r.Name, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
118. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p.Name, r.Name, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
119. make the smallest change that will remove that difference rule #3
120. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p, r, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
121. find the things that are most alike rule #1
122. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p, r, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
123. select the smallest difference between them rule #2
124. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, p, r, loc, ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
125. make the smallest change that will remove that difference rule #3
126. func text(l linker) string { return l.String() }
127. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, text(p), text(r), text(loc), ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
128. find the things that are most alike rule #1
129. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, text(p), text(r), text(loc), ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
130. select the smallest difference between them rule #2
131. msg := "%s discovered %s at %s." text := fmt.Sprintf( msg, text(p), text(r), text(loc), ) html := fmt.Sprintf( msg, link(p), link(r), link(loc), )
132. make the smallest change that will remove that difference rule #3
133. func text(l linker) string { return l.String() } func link(l linker) string { return fmt.Sprintf( "<a href='%s'>%s</a>", l.URL(), template.HTMLEscapeString(l.String()), ) }
134. func format(fn func(linker) string) string { // ... }
135. func format(..., fn func(linker) string, ...) string { // ... }
136. func format(msg string, fn func(linker) str... args := make([]interface{}, len(values)) for i, v := range values { args[i] = fn(v) } return fmt.Sprintf(msg, args...) }
137. func format(msg string, fn func(linker) str... args := make([]interface{}, len(values)) for i, v := range values { args[i] = fn(v) } return fmt.Sprintf(msg, args...) }
138. msg := "%s discovered %s at %s." text := fmt(msg, text, p, r, loc) html := fmt(msg, link, p, r, loc)
139. type message struct { template string vars []linker } func newMessage(template string, vars ...linker) message { return message{ template: template, vars: vars, } }
140. func (msg message) fmt(fn func(linker) string) string { args := make([]interface{}, len(msg.vars)) for i, v := range msg.vars { args[i] = fn(v) } return fmt.Sprintf(msg.template, args...) }
141. func (msg message) text() string { return msg.fmt(text) } func (msg message) html() string { return msg.fmt(link) }
142. s := "%s discovered %s at %s." msg := newMessage(s, p, r, loc) // ... msg.text() // ... msg.html()
143. text := fmt.Sprintf( "%s discovered %s at %s.", p.Name, r.Name, loc, ) html := fmt.Sprintf( "<a href='/people/%s'>%s</a> discovered "+ "<a href='/tribes/%s/resources/%s'>%s</a> "+ "at <a href='/maps?lat=%f&lon=%f'>%s</a>.", p.Handle, template.HTMLEscapeString(p.Name), r.TribeUUID(), r.UUID, template.HTMLEscapeString(r.Name), loc.Latitude, loc.Longitude, template.HTMLEscapeString(loc.String()), )
144. type message struct { template string vars []linker } func newMessage(template string, vars ...linker) message { return message{ template: template, vars: vars, } }
145. type message struct { template string vars []linker } func (msg message) text() string { return msg.fmt(text) } func (msg message) html() string { return msg.fmt(link) } func (msg message) fmt(fn func(linker) string) string { args := make([]interface{}, len(msg.vars)) for i, v := range msg.vars { args[i] = fn(v) } return fmt.Sprintf(msg.template, args...) }
146. type linker interface { String() string URL() string } func link(l linker) string { return fmt.Sprintf( "<a href='%s'>%s</a>", l.URL(), template.HTMLEscapeString(l.String()), ) } func text(l linker) string { return l.String() }
147. Flock to Abstractions
148. Thank You
149. ! Katrina Owen @kytrinyx