source_file = { SOI ~ function_definition ~ EOI }
function_definition = { fn_kw ~ identifier ~ lparen ~ parameter_list ~ rparen ~ primitive_type ~ block }
fn_kw = _{ "fn" }
identifier = @{ ASCII_ALPHA ~ ( ASCII_ALPHANUMERIC | "_" )* }
lparen = _{ "(" }
rparen = _{ ")" }
parameter_list = { ( number ~ comma )* ~ number? }
comma = _{ "," }
primitive_type = { "int" }
block = { lbrace ~ inner_block ~ rbrace }
inner_block = { return_statement }
lbrace = _{ "{" }
rbrace = _{ "}" }
return_statement = { return_kw ~ number ~ semi }
return_kw = _{ "return" }
number = @{ ASCII_DIGIT+ }
semi = _{ ";" }
WHITESPACE = _{ ( " " | "\t" | NEWLINE )+ }