3.13. $ - String interpolation

The $ special character identifies a string literal as an interpolated string. An interpolated string is a string literal that might contain interpolation expressions. String interpolation provides a more readable and convenient syntax to create formatted strings than a string concatenation or subst() method.

The following example uses both features to produce the same output:

local x = 123
local y = 567
print("x = {0}, sin(y) = {1}".subst(x, math.sin(y)))
print($"x = {x}, sin(y) = {math.sin(y)}")

Internally string interpolation translates to subst() call.

Nested interpolation strings are not supported.

To use curly brackets {} inside interpolation string, ‘{‘ and ‘}’ characters should be escaped using \

local foo = 123
print($"\{ foo = {foo} \}") // will output: { foo = 123 }