interpExp performs very simple interpolation of Haskell values into Strings.
Interpolated variables are prefixed with
$They can optionally be surrounded with braces like
${foo}Interpolated variables are converted to strings with show
To escape a
$use\$
let foo = 123 in $(interpExp "hello, $foo")"hello, 123"
let foo = "world" in $(interpExp "hello, \\$foo")"hello, $foo"
let foo = "world" in $(interpExp "hello\r\n\rworld")"hello\r\n\rworld"