substring ';' STRING ';' START ( ';' END )?

Summary

The substring macro extracts a portion of a string between start and end positions. It supports negative indices to count from the end of the string.

Syntax

${substring;<string>;<start>[;<end>]}

Parameters

• string - The source string
• start - Starting index (0-based, negative counts from end)
• end (optional) - Ending index (exclusive, negative counts from end, default: end of string)

Behavior

• Extracts substring from start (inclusive) to end (exclusive)
• Negative indices count from the end (-1 = last character)
• If start > end, they are automatically swapped
• Default end is the string length
• Returns the extracted substring

Examples

Get first 5 characters:

${substring;hello world;0;5}
# Returns: "hello"

Get last 5 characters:

${substring;hello world;-5}
# Returns: "world"

Remove first 2 characters:

${substring;hello;2}
# Returns: "llo"

Extract middle portion:

${substring;hello world;6;11}
# Returns: "world"

Use negative indices:

${substring;hello world;-5;-1}
# Returns: "worl"

Use Cases

• Extracting prefixes or suffixes
• Removing fixed-length headers
• Parsing formatted strings
• Getting file extensions
• Truncating strings
• String manipulation in templates

Notes

• Indices are 0-based (first character is 0)
• Negative indices count backwards from end
• End index is exclusive (not included in result)
• Start and end are swapped if start > end
• Throws exception if indices are out of bounds

See test cases in MacroTestsForDocsExamples.java