Alec Thomas
ab5cf7e6ef
* Add tracing to the parser. * Synthesize a --help flag. * Parsing now occurs in multiple phases. 1. Reset target. 2. Parse command-line into a "trace" (no values are written to target). 3. Apply traced, parsed values to the target fields. This is another step in facilitating context-sensitive help and completion. * Detect duplicate flags.
82 lines
1.6 KiB
Go
82 lines
1.6 KiB
Go
package kong
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import "reflect"
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type Application struct {
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Node
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HelpFlag *Flag
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}
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// A Branch is a command or positional argument that results in a branch in the command tree.
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type Branch struct {
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Command *Command
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Argument *Argument
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}
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type Command = Node
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type Node struct {
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Name string
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Help string
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Flags []*Flag
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Positional []*Value
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Children []*Branch
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}
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// A Value is either a flag or a variable positional argument.
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type Value struct {
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Flag bool // True if flag, false if positional argument.
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Name string
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Help string
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Default string
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Decoder Decoder
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Tag reflect.StructTag
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Value reflect.Value
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Required bool
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Set bool // Used with Required to test if a value has been given.
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Format string // Formatting directive, if applicable.
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}
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// Parse tokens into value, parse, and validate, but do not write to the field.
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func (v *Value) Parse(scan *Scanner) (reflect.Value, error) {
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value := reflect.New(v.Value.Type()).Elem()
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err := v.Decoder.Decode(&DecoderContext{Value: v}, scan, value)
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if err == nil {
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v.Set = true
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}
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return value, err
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}
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// Apply value to field.
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func (v *Value) Apply(value reflect.Value) {
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v.Value.Set(value)
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v.Set = true
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}
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func (v *Value) Reset() error {
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v.Value.Set(reflect.Zero(v.Value.Type()))
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if v.Default != "" {
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value, err := v.Parse(Scan(v.Default))
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if err != nil {
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return err
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}
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v.Apply(value)
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v.Set = false
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}
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return nil
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}
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type Positional = Value
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type Argument struct {
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Node
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Argument *Value
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}
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type Flag struct {
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Value
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Placeholder string
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Env string
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Short rune
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}
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