sexprs-parser 0.0.5

sexprs is a minimal lisp dialect to evaluate written in Rust.
Documentation 
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file                        = { SOI ~ (NEWLINE* ~ statement ~ NEWLINE*)* ~ EOI}

t                           = { "t" }
nil                         = { "nil" }
double_quoted_string        = _{ "\"" ~ string ~ "\"" }
unsigned                    = @{ ("0" | '1'..'9' ~ '0'..'9' * ) }
integer                     = @{ "-" ? ~ unsigned }
float                       = @{ "-" ? ~ unsigned ~ "." ~ unsigned? }
string                      = { (!("\"") ~ ANY)* }

double_quote                = @{ "\"" }
open_paren                  = @{ "(" }
quote                       = @{ "'" }
backquote                   = @{ "`" }
comma                       = @{ "," }
close_paren                 = @{ ")" }

nonsymbol                   = { open_paren | quote | backquote | comma | close_paren | double_quote | WHITESPACE }

statement                   = { sexpr+ }

value                       = { (t | nil | float | unsigned | integer | double_quoted_string) }
symbol                      = @{ ((!(nonsymbol | integer) ~ ANY)+) }
quoted_symbol               = ${ quote ~ symbol }

defun                       = { open_paren ~ "defun" ~ symbol_sexpr ~ sexpr* }
sexpr                       = { quote? ~ open_paren ~ (value | symbol | quoted_symbol | sexpr)* ~ close_paren }
symbol_sexpr                = { open_paren ~ symbol* ~ close_paren }

delimiter                   = _{ NEWLINE+ }
WHITESPACE                  = _{ " " | "\t" | "\n" }