Transform each element of a list using a macro function

Summary

The map macro applies a transformation function (specified as a macro name) to each element of one or more lists, collecting the results into a new comma-separated list. This is similar to the functional programming map operation.

Syntax 

${map;<macro-name>[;<list>...]}

Parameters

  • macro-name - Name of a macro to invoke for each element (without the ${} wrapper)
  • list - One or more semicolon-separated lists to process

Behavior

  • Combines all provided lists into a single list
  • For each element, invokes: ${<macro-name>;<element>}
  • Collects all transformation results
  • Returns results as a comma-separated string

Examples

Transform list elements:

# Define transformation macro
upper;${toupper;$1}

# Map to uppercase
${map;upper;apple,banana,cherry}

Add prefix to each element:

# Define prefix macro
add-prefix;modified-$1

${map;add-prefix;file1,file2,file3}
# Returns: "modified-file1,modified-file2,modified-file3"

Process file list:

# Define file processor
process;${basename;$1}

${map;process;/path/to/file1.jar;/path/to/file2.jar}
# Returns basenames of files

Calculate transformations:

# Define calculation macro
double;${multiply;$1;2}

${map;double;1,2,3,4,5}
# Returns: "2,4,6,8,10"

Use Cases

  • Transforming lists with complex logic
  • Applying consistent transformations to all elements
  • Building derived lists from source data
  • Functional-style list processing
  • Batch operations on list elements
  • Data transformation pipelines

Notes

  • The invoked macro receives one argument: the element value
  • Unlike ${foreach}, no index is passed to the macro
  • The macro must be defined before use (either as a property or built-in)
  • Results are joined with commas
  • Empty lists produce empty results
  • See also: ${foreach} for transformations that need the element index
  • See also: ${apply} for passing entire lists to a macro

See test cases in MacroTestsForDocsExamples.java