Documentation
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Index ¶
Constants ¶
const ( // ErrInvalidSpecification is returned when the struct // definition is impossible or incorrect. Always indicates an // error in the program. ErrInvalidSpecification = ers.Error("incorrect flag/configuration specification") // ErrInvalidInput is returned when a user has specified an // impossible or un-parsable input. ErrInvalidInput = ers.Error("received invalid/impossible flag/configuration") )
Variables ¶
This section is empty.
Functions ¶
func Parse ¶
Parse populates cfg from os.Args[1:] (or flag.CommandLine.Args() when a prior flag.Parse call has already consumed some arguments) using struct field tags, then validates required fields. cfg must be a pointer to a struct. Supported tags:
- flag:”name” flag name (required to register a field)
- default:”val” default value as a string
- help:”text” usage description
- short:”x” single-letter alias registered alongside the long name
- required:”true” field must be non-zero after parsing
Anonymous (embedded) struct fields are traversed with a flat namespace: only the `flag:` tag on each leaf field determines the flag name.
Named struct-typed fields behave differently depending on whether the field itself carries a `flag:` tag:
- With flag:”ns” tag: all leaf flags inside are registered as “-ns.<leaf>”, e.g. a field `Server net \`flag:”srv”\” containing `Host string \`flag:”host”\” produces the flag “-srv.host”.
- Without a flag: tag: the field name is ignored and leaf flags are registered with a flat namespace (same as anonymous embedding).
Namespaces nest: a named struct inside another named struct accumulates prefixes separated by “.”.
Supported field types: string, bool, int, int64, uint, uint64, float64, time.Time, time.Duration, and slices thereof.
Fields tagged cmd: are silently skipped; use ParseCommand or Dispatch for subcommand-aware parsing.
Types ¶
type Commander ¶
Commander is implemented by every subcommand struct that can be dispatched to. Parse/conflagure populate the struct's flags first, then the caller is responsible for invoking Run.
func Dispatch ¶
Dispatch identifies the subcommand from flag.CommandLine.Args() (i.e. the remaining arguments after a prior call to Parse) and parses that subcommand's flags. It returns the selected Commander, or nil if no subcommand was matched and none is required. cfg must be the same pointer passed to Parse.
Use ParseCommand when you want a single call that does both phases.
func ParseCommand ¶
ParseCommand parses global flags (via commandLineArgs) and then identifies and parses the subcommand, returning the selected Commander. It is equivalent to calling Parse followed by Dispatch.
Returns (nil, nil) when no cmd: fields are defined or when the invocation contains only global flags and no subcommand is required.
If cfg itself implements Commander and no subcommand is selected, cfg is returned as the Commander.
Source Files