Remove duplicate elements from one or more lists

Summary

The uniq macro combines one or more lists and removes all duplicate elements, preserving insertion order (first occurrence is kept).

Syntax 

${uniq;<list>[;<list>...]}

Parameters

  • list - One or more semicolon-separated lists to process

Behavior

  • Combines all provided lists
  • Removes duplicate elements
  • Preserves insertion order (first occurrence kept)
  • Returns comma-separated list of unique elements

Examples

Remove duplicates from single list:

${uniq;1,2,3,1,2,4}
# Returns: "1,2,3,4"

Remove duplicates from multiple lists:

${uniq;red,green,blue;red,yellow}
# Returns: "red,green,blue,yellow"

Clean package list:

${uniq;${exports};${imports}}
# Returns unique packages

Deduplicate configuration:

unique.values=${uniq;${list1};${list2};${list3}}

Use Cases

  • Removing duplicate entries from lists
  • Merging lists without duplicates
  • Creating unique sets from multiple sources
  • Cleaning up configuration values
  • Deduplicating package or class lists
  • Set operations on lists

Notes

  • Preserves insertion order (LinkedHashSet behavior)
  • First occurrence of duplicate is kept
  • Case-sensitive comparison
  • Empty elements are preserved if present
  • See also: ${sort} to also sort the result
  • See also: ${removeall} and ${retainall} for set operations

See test cases in MacroTestsForDocsExamples.java