varsubstitution.groovy

varsubstitution.groovy

// String variable substitutions
def parseVariableNames(String text) {
	def names = []
	def pos = 0, max = text.length()
	while (pos < max) {
		pos = text.indexOf('${', pos)
		if (pos == -1)
			break
		def end = text.indexOf('}', pos + 2)
		if (end == -1)
			break
		def name = text.substring(pos + 2, end)
		names.add(name)
		pos = end + 1
	}
	return names
}
def replaceVariable(String key, String value, String text) {
	//println "DEBUG: Replacing '${key}'' with '${value}'"
	result = text.replaceAll('\\$\\{' + key + '}', value)
	return result
}

// Test
def map = ["name": "Zemian", "id": "1001"]
def inputs  = [
	'Hello ${name}',
	'My id is ${id}',
	'${name} is a good programmer.',
	'${name}\'s id is ${id}.'
]

result = inputs.collect{ line ->
	def names = parseVariableNames(line)
	names.each{ key ->
		line = replaceVariable(key, map.get(key), line) 
	}
	line
}
assert result == [
	'Hello Zemian',
	'My id is 1001',
	'Zemian is a good programmer.',
	'Zemian\'s id is 1001.'
]