Documentation
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Overview ¶
Package expander provides an extension for representing expandable expressions in command line arguments. The main use case is for dynamically evaluating these expressions with values that occur during the execution of the evaluators.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var Nil = Func(nilImpl)
Nil provides an expander which always provides nil
Functions ¶
Types ¶
type ErrUnknownToken ¶
type ErrUnknownToken string
func (ErrUnknownToken) Error ¶
func (e ErrUnknownToken) Error() string
type Interface ¶
Interface converts the given string key into its variable expansion
func Prefix ¶
Prefix provides an expander which looks for and cuts a given prefix and delegates the result to the underlying expander
func Reflect ¶ added in v0.12.0
Reflect provides a simple expander around a given value using reflection
type Pattern ¶
type Pattern struct {
// contains filtered or unexported fields
}
func CompilePattern ¶
func (*Pattern) ExpandAny ¶ added in v0.16.0
ExpandAny expands the pattern, returning the underlying type of the expansion when the pattern consists of a single expression with no format specifier applied.. When the pattern has multiple expressions, a literal fallback, or a format specifier, it falls back to string interpolation like Expand.
func (*Pattern) Fprint ¶ added in v0.16.0
Fprint expands the pattern using the given expander and writes to the specified writer. As a special case, if w has a method Expander() Interface, this method will be called to obtain an expander which composes with the expander e. The main use of this convention is to allow writers to supply control expressions. For an example, see Renderer.
type Renderer ¶
Renderer is a specialized writer that understands writing to multiple files and the corresponding variable support. When used as a writer to Fprint, two control expressions are exposed, stdout and stderr, which can be used to redirect to the underlying writers. For example, "%(stderr)debug: %(v:#v)%(newline)%(stdout)%(v)" would print debug text to whatever writer was set for stderr.
func NewRenderer ¶
type Syntax ¶
type Syntax int
const ( // SyntaxDefault indicates that the expression syntax uses the // form <name>[':' <format>]. That is, an optional format string is allowed // to control the output. SyntaxDefault Syntax = iota // SyntaxRecursive causes recursive expression evaluation to // be allowed. For example, the expression ${VISUAL:${EDITOR}} // would evaluate both environment variables, falling back to EDITOR. SyntaxRecursive )
Source Files