extend("string")
# 1) Direct usage: Provide both parameters now
result = string:concat("Hello, ", "World!")
sput(result) // => "Hello, World!"
# 2) Partial usage: Provide only the first parameter
myConcat = string:concat("abc")
resultA = myConcat("def")
sput(resultA) // => "abcdef"
resultB = myConcat("xyz")
sput(resultB) // => "abcxyz"
# 3) Partial usage with underscore placeholder for the first parameter
myConcat2 = string:concat(_, "World!")
sput( myConcat2("Hello, ") ) // => "Hello, World!"
sput( myConcat2("Greetings, ") ) // => "Greetings, World!"