forked from djcas9/envdb
-
Notifications
You must be signed in to change notification settings - Fork 0
/
args.go
160 lines (142 loc) · 3.22 KB
/
args.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
package kingpin
import "fmt"
type argGroup struct {
args []*ArgClause
}
func newArgGroup() *argGroup {
return &argGroup{}
}
func (a *argGroup) have() bool {
return len(a.args) > 0
}
func (a *argGroup) Arg(name, help string) *ArgClause {
arg := newArg(name, help)
a.args = append(a.args, arg)
return arg
}
func (a *argGroup) parse(context *ParseContext) error {
i := 0
var last *Token
consumed := 0
for i < len(a.args) {
arg := a.args[i]
token := context.Peek()
if token.Type == TokenEOL {
if consumed == 0 && arg.required {
return fmt.Errorf("'%s' is required", arg.name)
}
break
}
var err error
err = arg.parse(context)
if err != nil {
return err
}
if arg.consumesRemainder() {
if last == context.Peek() {
return fmt.Errorf("expected positional arguments <%s> but got '%s'", arg.name, last)
}
consumed++
} else {
i++
}
last = token
}
// Set defaults for all remaining args.
for i < len(a.args) {
arg := a.args[i]
if arg.defaultValue != "" {
if err := arg.value.Set(arg.defaultValue); err != nil {
return fmt.Errorf("invalid default value '%s' for argument '%s'", arg.defaultValue, arg.name)
}
}
i++
}
return nil
}
func (a *argGroup) init() error {
required := 0
seen := map[string]struct{}{}
previousArgMustBeLast := false
for i, arg := range a.args {
if previousArgMustBeLast {
return fmt.Errorf("Args() can't be followed by another argument '%s'", arg.name)
}
if arg.consumesRemainder() {
previousArgMustBeLast = true
}
if _, ok := seen[arg.name]; ok {
return fmt.Errorf("duplicate argument '%s'", arg.name)
}
seen[arg.name] = struct{}{}
if arg.required && required != i {
return fmt.Errorf("required arguments found after non-required")
}
if arg.required {
required++
}
if err := arg.init(); err != nil {
return err
}
}
return nil
}
type ArgClause struct {
parserMixin
name string
help string
defaultValue string
required bool
dispatch Dispatch
}
func newArg(name, help string) *ArgClause {
a := &ArgClause{
name: name,
help: help,
}
return a
}
func (a *ArgClause) consumesRemainder() bool {
if r, ok := a.value.(remainderArg); ok {
return r.IsCumulative()
}
return false
}
// Required arguments must be input by the user. They can not have a Default() value provided.
func (a *ArgClause) Required() *ArgClause {
a.required = true
return a
}
// Default value for this argument. It *must* be parseable by the value of the argument.
func (a *ArgClause) Default(value string) *ArgClause {
a.defaultValue = value
return a
}
func (a *ArgClause) Dispatch(dispatch Dispatch) *ArgClause {
a.dispatch = dispatch
return a
}
func (a *ArgClause) init() error {
if a.required && a.defaultValue != "" {
return fmt.Errorf("required argument '%s' with unusable default value", a.name)
}
if a.value == nil {
return fmt.Errorf("no parser defined for arg '%s'", a.name)
}
return nil
}
func (a *ArgClause) parse(context *ParseContext) error {
token := context.Peek()
if token.Type == TokenArg {
if err := a.value.Set(token.Value); err != nil {
return err
}
if a.dispatch != nil {
if err := a.dispatch(context); err != nil {
return err
}
}
context.Next()
}
return nil
}