Package org.jline.reader

Interface Expander

All Known Implementing Classes:

DefaultExpander

public interface Expander

The Expander interface provides functionality for expanding special syntax in command lines.

Expanders are responsible for processing and expanding various types of expressions in the input line before it is executed. This includes:

• History expansions (e.g., !! to repeat the last command)
• Variable expansions (e.g., $HOME or ${HOME})
• Other shell-like expansions

The expander is called by the LineReader after the user has accepted a line but before it is executed or added to the history. This allows the user to see the unexpanded form while editing, but ensures that the expanded form is what gets executed and stored in history.

The default implementation is DefaultExpander.

See Also:

• DefaultExpander
• LineReader.getExpander()
• LineReaderBuilder.expander(Expander)

Method Summary

Modifier and Type	Method	Description
String	expandHistory(History history, String line)	Expands history references in the input line.
String	expandVar(String word)	Expands variables in the input word.

Method Details

expandHistory

String expandHistory(History history,
 String line)

Expands history references in the input line.

This method processes history designators such as !!, !$, !n, etc., replacing them with the corresponding entries from the command history.

Parameters:

history - the command history to use for expansion

line - the input line containing history references

Returns:

the line with history references expanded

expandVar

String expandVar(String word)

Expands variables in the input word.

This method processes variable references such as $VAR or ${VAR}, replacing them with their values. The specific syntax and behavior depends on the implementation.

Parameters:

word - the word containing variable references

Returns:

the word with variables expanded