//! This grammar is a Ocypode programming language grammar.
//! It is used to parse Ocypode source code into an AST.
//! For more information about Ocypode, see https://github.com/TheAwiteb/ocypode-lang

WHITESPACE = _{ WHITE_SPACE }
COMMENT    = _{ comment_line | comment_block }
IDENT      = @{ !reserved ~ (ASCII_ALPHA | "_") ~ (ASCII_ALPHANUMERIC | "_")* }

PUBLIC     =  { "^" }
PRIVATE    =  { "" }
visibility = ${ (PUBLIC | PRIVATE) ~ !LETTER }
semicolon  =  { ";" }
keyword    =  { ("return") ~ !LETTER }
reserved   =  { (keyword | boolean | nil) ~ !LETTER }

comment_line        = _{ "//" ~ (!NEWLINE ~ ANY)* }
start_comment_block = _{ "/*" }
end_comment_block   = _{ "*/" }
comment_block       = _{ start_comment_block ~ (!end_comment_block ~ ANY)* ~ end_comment_block }

string_delimiter = _{ "\"" }
string_escape    =  { "\\" ~ (string_delimiter | "\\" | "n" | "r" | "t") }

string  = @{ string_delimiter ~ (string_escape | !(string_delimiter | "\\") ~ ANY)* ~ string_delimiter }
integer = @{ ("0" | ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*) }
float   = @{ integer ~ "." ~ ASCII_DIGIT+ }
boolean = @{ ("true" | "false") ~ !LETTER }
nil     = @{ "nil" ~ !LETTER }
array   =  { "[" ~ !"," ~ (expression ~ ("," ~ expression)*)? ~ ","? ~ "]" }

value = { string | float | integer | boolean | array | nil | IDENT }

pack                      = ${ "*" | "" }
unpack                    = ${ "..." | "" }
param                     = ${ "<" ~ pack ~ IDENT ~ ">" }
params                    =  { param* }
anonymous_function_params =  { ("<" ~ ">") | param+ }
arg                       =  { "<" ~ unpack ~ expression ~ ">" }
args                      =  { ("<" ~ ">") | arg+ }
block                     =  { "{<" ~ (statement ~ semicolon)* ~ ">}" }
func_def                  =  { visibility ~ "~" ~ IDENT ~ params ~ block }
anonymous_function        =  { anonymous_function_params ~ block }
func_call                 =  { (IDENT | anonymous_function) ~ args }

return_stmt = { "return" ~ expression }
assignment  = { IDENT ~ "=" ~ expression }

expression = { func_call | anonymous_function | value }
statement  = { func_def | assignment | return_stmt | expression }

program = { SOI ~ func_def* ~ EOI }