var = { (ASCII_ALPHANUMERIC | "_")+ }
default = { (ASCII_ALPHANUMERIC | "_")+ }
input = { var ~ (whitespace* ~ "=" ~ whitespace* ~ default)* }
whitespace = _{ "\t" | " " }
var_placeholder = _{ "{{" ~ whitespace* ~ var ~ whitespace* ~ "}}" }
input_placeholder = _{ "[[" ~ whitespace* ~ input ~ whitespace* ~ "]]" }
word = { (!("{{"|"[[") ~ ANY)+ }
text = { SOI ~ (var_placeholder | input_placeholder | word)* }