Merge pull request #12 from erindesu/master

Cargo.lock

@@ -9,6 +9,7 @@ dependencies = [
  "clap",
  "logos",
  "rand",
+ "rustyline",
 ]
 
 [[package]]
@@ -43,6 +44,12 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "cc"
+version = "1.0.67"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3c69b077ad434294d3ce9f1f6143a2a4b89a8a2d54ef813d85003a4fd1137fd"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -64,12 +71,49 @@ dependencies = [
  "vec_map",
 ]
 
+[[package]]
+name = "dirs-next"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b98cf8ebf19c3d1b223e151f99a4f9f0690dca41414773390fc824184ac833e1"
+dependencies = [
+ "cfg-if",
+ "dirs-sys-next",
+]
+
+[[package]]
+name = "dirs-sys-next"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ebda144c4fe02d1f7ea1a7d9641b6fc6b580adcfa024ae48797ecdeb6825b4d"
+dependencies = [
+ "libc",
+ "redox_users",
+ "winapi",
+]
+
+[[package]]
+name = "endian-type"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c34f04666d835ff5d62e058c3995147c06f42fe86ff053337632bca83e42702d"
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 
+[[package]]
+name = "fs2"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.2"
@@ -96,6 +140,15 @@ version = "0.2.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9385f66bf6105b241aa65a61cb923ef20efc665cb9f9bb50ac2f0c4b7f378d41"
 
+[[package]]
+name = "log"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "logos"
 version = "0.12.0"
@@ -120,6 +173,33 @@ dependencies = [
  "utf8-ranges",
 ]
 
+[[package]]
+name = "memchr"
+version = "2.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+
+[[package]]
+name = "nibble_vec"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a5d83df9f36fe23f0c3648c6bbb8b0298bb5f1939c8f2704431371f4b84d43"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "nix"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa9b4819da1bc61c0ea48b63b7bc8604064dd43013e7cc325df098d49cd7c18a"
+dependencies = [
+ "bitflags",
+ "cc",
+ "cfg-if",
+ "libc",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.10"
@@ -144,6 +224,16 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "radix_trie"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c069c179fcdc6a2fe24d8d18305cf085fdbd4f922c041943e203685d6a1c58fd"
+dependencies = [
+ "endian-type",
+ "nibble_vec",
+]
+
 [[package]]
 name = "rand"
 version = "0.8.3"
@@ -184,12 +274,66 @@ dependencies = [
  "rand_core",
 ]
 
+[[package]]
+name = "redox_syscall"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85dd92e586f7355c633911e11f77f3d12f04b1b1bd76a198bd34ae3af8341ef2"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
+name = "redox_users"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "528532f3d801c87aec9def2add9ca802fe569e44a544afe633765267840abe64"
+dependencies = [
+ "getrandom",
+ "redox_syscall",
+]
+
 [[package]]
 name = "regex-syntax"
 version = "0.6.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "24d5f089152e60f62d28b835fbff2cd2e8dc0baf1ac13343bef92ab7eed84548"
 
+[[package]]
+name = "rustyline"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e1b597fcd1eeb1d6b25b493538e5aa19629eb08932184b85fef931ba87e893"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "dirs-next",
+ "fs2",
+ "libc",
+ "log",
+ "memchr",
+ "nix",
+ "radix_trie",
+ "scopeguard",
+ "smallvec",
+ "unicode-segmentation",
+ "unicode-width",
+ "utf8parse",
+ "winapi",
+]
+
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
+[[package]]
+name = "smallvec"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
+
 [[package]]
 name = "strsim"
 version = "0.8.0"
@@ -216,6 +360,12 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
+
 [[package]]
 name = "unicode-width"
 version = "0.1.8"
@@ -234,6 +384,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4ae116fef2b7fea257ed6440d3cfcff7f190865f170cdad00bb6465bf18ecba"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "936e4b492acfd135421d8dca4b1aa80a7bfc26e702ef3af710e0752684df5372"
+
 [[package]]
 name = "vec_map"
 version = "0.8.2"

Cargo.toml

@@ -10,3 +10,4 @@ edition = "2018"
 clap="*"
 logos = "0.12"
 rand = "*"
+rustyline = "8.0.0"

README.md

@@ -1,4 +1,4 @@
-# Ablescript
+# AbleScript
 ![Lines of code](https://img.shields.io/tokei/lines/github/abletheabove/able-script)
 
 Bravely going where some languages have gone before.

able-script-test/melo-hello.able

@@ -1,3 +1,3 @@
 var hi = "wonk";
 melo hi;
-hi print; #Should error out
+hi print; # Should error out

able-script-test/parse_test.able

@@ -1,3 +0,0 @@
-if (true) {
-    var a = 3;
-}

src/lexer.rs

@@ -1,7 +1,65 @@
-use logos::{Lexer, Logos};
+use logos::{Lexer, Logos, Span};
 
 use crate::variables::Abool;
 
+pub struct PeekableLexer<'source> {
+    lexer: Lexer<'source, Token>,
+    peeked: Option<Option<Token>>,
+}
+
+impl<'source> PeekableLexer<'source> {
+    pub fn lexer(source: &'source str) -> Self {
+        Self {
+            lexer: Token::lexer(source),
+            peeked: None,
+        }
+    }
+
+    /// Returns a reference to the next() value without advancing the iterator.
+    #[inline]
+    pub fn peek(&mut self) -> &Option<Token> {
+        if self.peeked.is_none() {
+            self.peeked = Some(self.lexer.next());
+        }
+        self.peeked.as_ref().unwrap()
+    }
+
+    /// Get the range for the current token in `Source`.
+    #[inline]
+    pub fn span(&self) -> Span {
+        self.lexer.span()
+    }
+
+    /// Get a string slice of the current token.
+    #[inline]
+    pub fn slice(&self) -> &'source str {
+        self.lexer.slice()
+    }
+
+    /// Get a slice of remaining source, starting at the end of current token.
+    #[inline]
+    pub fn remainder(&self) -> &'source str {
+        self.lexer.remainder()
+    }
+}
+
+impl<'source> Iterator for PeekableLexer<'source> {
+    type Item = Token;
+
+    /// Advances the iterator and returns the next value.
+    ///
+    /// Returns [`None`] when iteration is finished.
+    /// Individual iterator implementations may choose to resume iteration, and so calling `next()`
+    /// again may or may not eventually start returning [`Some(Item)`] again at some point.
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.peeked.take() {
+            Some(v) => v,
+            None => self.lexer.next(),
+        }
+    }
+}
+
 #[derive(Logos, Debug, PartialEq, Clone)]
 pub enum Token {
     #[token("functio")]
@@ -36,6 +94,12 @@ pub enum Token {
     #[token("loop")]
     Loop,
 
+    #[token("break")]
+    Break,
+
+    #[token("hopback")]
+    HopBack,
+
     // Literals
     /// True, False
     #[regex("true|false", get_bool)]
@@ -57,6 +121,9 @@ pub enum Token {
     #[regex(r"[a-zA-Z_][a-zA-Z_0-9]*", get_iden)]
     Identifier(String),
 
+    #[regex("nul")]
+    Nul,
+
     #[token("(")]
     LeftParenthesis,
 
@@ -116,6 +183,15 @@ pub enum Token {
     #[token("!=")]
     OpNeq,
 
+    #[token("&")]
+    LogAnd,
+
+    #[token("|")]
+    LogOr,
+
+    #[token("!")]
+    LogNot,
+
     /// Base52 based character ('a')
     #[token("'.*'")]
     Char,

src/main.rs

@@ -2,11 +2,13 @@
 
 mod base_55;
 mod error;
+mod lexer;
 mod parser;
-mod tokens;
+mod repl;
 mod variables;
 
 use clap::{App, Arg};
+use logos::Source;
 use parser::Parser;
 fn main() {
     // variables::test();
@@ -14,7 +16,7 @@ fn main() {
     let matches = App::new("AbleScript")
         .version(env!("CARGO_PKG_VERSION"))
         .author("Able <abl3theabove@gmail.com>")
-        .about("Does awesome things")
+        .about("AbleScript interpreter")
         .arg(
             Arg::with_name("file")
                 .short("f")
@@ -33,11 +35,24 @@ fn main() {
             // Parse
             let mut parser = Parser::new(&source);
             let ast = parser.init();
-            println!("{:#?}", ast);
+            match ast {
+                Ok(ast) => println!("{:#?}", ast),
+                Err(e) => {
+                    println!(
+                        "Error `{:?}` occured at span: {:?} = `{:?}`",
+                        e.kind,
+                        e.position.clone(),
+                        source.slice(e.position)
+                    );
+                }
+            }
         }
         None => {
-            println!("hi");
+            println!(
-            //start the prompt
+                "Hi [AbleScript {}] - AST Printer",
+                env!("CARGO_PKG_VERSION")
+            );
+            repl::repl();
         }
     }
 }

src/parser/item.rs

@@ -1,27 +1,82 @@
 use crate::variables::Value;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct Iden(pub String);
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
+pub enum Item {
+    Expr(Expr),
+    Stmt(Stmt),
+}
+
+impl From<Expr> for Item {
+    fn from(e: Expr) -> Self {
+        Item::Expr(e)
+    }
+}
+
+impl From<Iden> for Item {
+    fn from(i: Iden) -> Self {
+        Item::Expr(Expr::Identifier(i))
+    }
+}
+
+impl From<Stmt> for Item {
+    fn from(s: Stmt) -> Self {
+        Item::Stmt(s)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
 pub enum Expr {
+    Add { left: Box<Expr>, right: Box<Expr> },
+    Subtract { left: Box<Expr>, right: Box<Expr> },
+    Multiply { left: Box<Expr>, right: Box<Expr> },
+    Divide { left: Box<Expr>, right: Box<Expr> },
+    Lt { left: Box<Expr>, right: Box<Expr> },
+    Gt { left: Box<Expr>, right: Box<Expr> },
+    Eq { left: Box<Expr>, right: Box<Expr> },
+    Neq { left: Box<Expr>, right: Box<Expr> },
+    And { left: Box<Expr>, right: Box<Expr> },
+    Or { left: Box<Expr>, right: Box<Expr> },
+    Not(Box<Expr>),
+    Literal(Value),
+    Identifier(Iden),
+}
+impl From<Iden> for Expr {
+    fn from(i: Iden) -> Self {
+        Self::Identifier(i)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Stmt {
     VariableDeclaration {
-        iden: String,
+        iden: Iden,
-        init: Option<Box<Expr>>,
+        init: Option<Box<Item>>,
     },
     FunctionDeclaration {
-        iden: String,
+        iden: Iden,
-        body: Vec<Expr>,
+        args: Vec<Iden>,
+        body: Vec<Item>,
     },
     BfFDeclaration {
-        iden: String,
+        iden: Iden,
         body: String,
     },
     If {
-        cond: Box<Expr>,
+        cond: Box<Item>,
-        body: Vec<Expr>,
+        body: Vec<Item>,
     },
-
+    FunctionCall {
-    Literal(Value),
+        iden: Iden,
+        args: Vec<Expr>,
+    },
+    Loop {
+        body: Vec<Item>,
+    },
+    Break,
+    HopBack,
+    Print(Expr),
     Melo(Iden),
 }

src/parser/mod.rs

@@ -1,44 +1,56 @@
 mod item;
+mod ops;
 mod utils;
 
-use item::Expr;
+use item::Item;
 
 use crate::{
     error::{Error, ErrorKind},
+    lexer::PeekableLexer,
+    parser::item::{Expr, Stmt},
     variables::Value,
 };
-use crate::{parser::item::Iden, tokens::Token};
+use crate::{lexer::Token, parser::item::Iden};
 
-use logos::Logos;
+pub type ParseResult = Result<Item, Error>;
 
 /// Parser structure / state machine
 pub struct Parser<'a> {
-    lexer: logos::Lexer<'a, Token>,
+    lexer: PeekableLexer<'a>,
-    ast: Vec<Expr>,
+    ast: Vec<Item>,
+    tdark: bool,
 }
 
 impl<'a> Parser<'a> {
     /// Create a new parser object
     pub fn new(source: &'a str) -> Self {
         Self {
-            lexer: Token::lexer(source),
+            lexer: PeekableLexer::lexer(source),
             ast: Vec::new(),
+            tdark: false,
         }
     }
 
-    pub fn init(&mut self) -> Result<Vec<Expr>, Error> {
+    pub fn init(&mut self) -> Result<Vec<Item>, Error> {
         loop {
             let token = self.lexer.next();
-            if token.is_none() {
-                return Ok(self.ast.clone());
-            };
 
-            let expr = self.parse_expr(token)?;
+            match token {
-            self.ast.push(expr);
+                Some(Token::Comment) => continue,
+                Some(Token::TDark) => {
+                    let mut block = self.tdark_block()?;
+                    self.ast.append(&mut block);
+                }
+                None => return Ok(self.ast.clone()),
+                _ => {
+                    let item = self.parse_item(token)?;
+                    self.ast.push(item);
+                }
+            }
         }
     }
 
-    fn parse_expr(&mut self, token: Option<Token>) -> Result<Expr, Error> {
+    fn parse_item(&mut self, token: Option<Token>) -> ParseResult {
         if matches!(token, None) {
             return Err(Error {
                 kind: ErrorKind::EndOfTokenStream,
@@ -50,26 +62,38 @@ impl<'a> Parser<'a> {
         let start = self.lexer.span().start;
 
         match token {
+            Token::Identifier(_)
+            | Token::Aboolean(_)
+            | Token::Boolean(_)
+            | Token::Integer(_)
+            | Token::String(_)
+            | Token::Nul
+            | Token::LogNot => self.parse_ops(token),
+
             // Control flow
             Token::If => self.if_cond(),
+            Token::Loop => self.loop_block(),
+
+            Token::HopBack => {
+                self.require(Token::Semicolon)?;
+                Ok(Stmt::HopBack.into())
+            }
+            Token::Break => {
+                self.require(Token::Semicolon)?;
+                Ok(Stmt::Break.into())
+            }
 
             // Declarations
             Token::Variable => self.variable_declaration(),
             Token::Function => self.function_declaration(),
             Token::BfFunction => self.bff_declaration(),
 
-            // Literals
-            Token::String(x) => Ok(Expr::Literal(Value::Str(x))),
-            Token::Integer(x) => Ok(Expr::Literal(Value::Int(x))),
-            Token::Boolean(x) => Ok(Expr::Literal(Value::Bool(x))),
-            Token::Aboolean(x) => Ok(Expr::Literal(Value::Abool(x))),
-
             // Prefix keywords
             // Melo - ban variable from next usage (runtime error)
             Token::Melo => {
                 let e = self.require_iden()?;
                 self.require(Token::Semicolon)?;
-                Ok(Expr::Melo(Iden(e)))
+                Ok(Stmt::Melo(e).into())
             }
 
             _ => Err(Error {
@@ -82,14 +106,14 @@ impl<'a> Parser<'a> {
     /// Parse variable declaration
     ///
     /// `var [iden] = [literal];`
-    fn variable_declaration(&mut self) -> Result<Expr, Error> {
+    fn variable_declaration(&mut self) -> ParseResult {
         let iden = self.require_iden()?;
 
         let init = match self.lexer.next() {
             Some(Token::Semicolon) => None,
             Some(Token::Assignment) => {
                 let value = self.lexer.next();
-                let value = self.parse_expr(value)?;
+                let value = self.parse_item(value)?;
                 self.require(Token::Semicolon)?;
                 Some(Box::new(value))
             }
@@ -101,28 +125,35 @@ impl<'a> Parser<'a> {
             }
         };
 
-        Ok(Expr::VariableDeclaration { iden, init })
+        Ok(Stmt::VariableDeclaration { iden, init }.into())
     }
 
     /// Declare function
     ///
     /// `functio [iden] ([expr], [expr]) { ... }
-    fn function_declaration(&mut self) -> Result<Expr, Error> {
+    fn function_declaration(&mut self) -> ParseResult {
         let iden = self.require_iden()?;
         self.require(Token::LeftParenthesis)?;
-        self.require(Token::RightParenthesis)?;
+        let mut args = vec![];
-
+        loop {
+            let next = self.lexer.next();
+            match next {
+                Some(Token::RightParenthesis) => break,
+                Some(Token::Identifier(i)) => args.push(Iden(i)),
+                _ => return Err(self.unexpected_token(None)),
+            }
+        }
         self.require(Token::LeftBrace)?;
         // Parse function body
         let body = self.parse_body()?;
 
-        Ok(Expr::FunctionDeclaration { iden, body })
+        Ok(Stmt::FunctionDeclaration { iden, args, body }.into())
     }
 
     /// Declare BF FFI Function
     ///
     /// `bff [iden] { ... }`
-    fn bff_declaration(&mut self) -> Result<Expr, Error> {
+    fn bff_declaration(&mut self) -> ParseResult {
         let iden = self.require_iden()?;
         self.require(Token::LeftBrace)?;
 
@@ -140,9 +171,6 @@ impl<'a> Parser<'a> {
                 }
             };
 
-            if token == Token::RightBrace {
-                break;
-            }
             body.push_str(match token {
                 Token::OpGt
                 | Token::OpLt
@@ -156,23 +184,118 @@ impl<'a> Parser<'a> {
                 _ => return Err(self.unexpected_token(None)),
             });
         }
-        Ok(Expr::BfFDeclaration { iden, body })
+        Ok(Stmt::BfFDeclaration { iden, body }.into())
     }
 
-    /// Parse If-expression
+    /// Parse If-stmt
-    pub fn if_cond(&mut self) -> Result<Expr, Error> {
+    pub fn if_cond(&mut self) -> ParseResult {
         self.require(Token::LeftParenthesis)?;
         let cond = self.lexer.next();
-        let cond = self.parse_expr(cond)?;
+        let cond = self.parse_item(cond)?;
         self.require(Token::RightParenthesis)?;
 
         self.require(Token::LeftBrace)?;
 
         let body = self.parse_body()?;
 
-        Ok(Expr::If {
+        Ok(Stmt::If {
             cond: Box::new(cond),
             body,
-        })
+        }
+        .into())
+    }
+
+    /// Parse loop
+    pub fn loop_block(&mut self) -> ParseResult {
+        self.require(Token::LeftBrace)?;
+        let body = self.parse_body()?;
+
+        Ok(Stmt::Loop { body }.into())
+    }
+
+    /// T-Dark block parsing
+    pub fn tdark_block(&mut self) -> Result<Vec<Item>, Error> {
+        self.require(Token::LeftBrace)?;
+        self.tdark = true;
+        let mut body = Vec::new();
+        loop {
+            let token = {
+                match self.lexer.next() {
+                    Some(t) => t,
+                    None => {
+                        return Err(Error {
+                            kind: ErrorKind::EndOfTokenStream,
+                            position: self.lexer.span(),
+                        })
+                    }
+                }
+            };
+
+            if token == Token::RightBrace {
+                break;
+            }
+            body.push(self.parse_item(Some(token))?);
+        }
+        self.tdark = false;
+        Ok(body)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use Expr::*;
+    use Stmt::*;
+
+    #[test]
+    fn control_flow() {
+        let code = r#"loop { var a = 3 + 2; if (a == 5) { break; } }"#;
+
+        let expected: &[Item] = &[Item::Stmt(Loop {
+            body: vec![
+                VariableDeclaration {
+                    iden: Iden("a".to_owned()),
+                    init: Some(Box::new(
+                        Add {
+                            left: Box::new(Literal(Value::Int(3))),
+                            right: Box::new(Literal(Value::Int(2))),
+                        }
+                        .into(),
+                    )),
+                }
+                .into(),
+                If {
+                    cond: Box::new(
+                        Eq {
+                            left: Box::new(Iden("a".to_owned()).into()),
+                            right: Box::new(Literal(Value::Int(5)).into()),
+                        }
+                        .into(),
+                    ),
+                    body: vec![Break.into()],
+                }
+                .into(),
+            ],
+        })];
+        let ast = Parser::new(code).init().unwrap();
+
+        assert_eq!(ast, expected)
+    }
+
+    #[test]
+    fn tdark() {
+        let code = r#"T-Dark { var lang = nul; lang print; }"#;
+        let expected: &[Item] = &[
+            VariableDeclaration {
+                iden: Iden("script".to_owned()),
+                init: Some(Box::new(Literal(Value::Nul).into())),
+            }
+            .into(),
+            Print(Iden("script".to_owned()).into()).into(),
+        ];
+
+        let ast = Parser::new(code).init().unwrap();
+
+        assert_eq!(ast, expected)
     }
 }

src/parser/ops.rs

@@ -0,0 +1,159 @@
+use super::*;
+
+type ExprResult = Result<Expr, Error>;
+
+/// Generate infix expression by pattern left <op> right
+///
+/// Credits: `@! ! Reiter#4543`
+#[macro_export]
+macro_rules! gen_infix {
+    ($($fn_name: ident => $type: tt);*$(;)?) => {$(
+        /// Generated function for infix operator
+        fn $fn_name(&mut self, left: Expr) -> ExprResult {
+            self.lexer.next();
+            let next = self.lexer.next();
+            let right = self.parse_expr(next)?;
+            Ok(Expr::$type { left: Box::new(left), right: Box::new(right) })
+        })*
+    };
+}
+
+impl<'a> Parser<'a> {
+    pub(super) fn parse_ops(&mut self, token: Token) -> ParseResult {
+        if matches!(self.lexer.peek(), Some(Token::LeftParenthesis)) {
+            return self.fn_call(token);
+        }
+
+        let mut buf: Expr = self.parse_expr(Some(token))?;
+
+        loop {
+            buf = match self.lexer.peek() {
+                Some(Token::Addition) => self.addition(buf)?,
+                Some(Token::Subtract) => self.subtract(buf)?,
+                Some(Token::Multiply) => self.multiply(buf)?,
+                Some(Token::Divide) => self.divide(buf)?,
+                Some(Token::OpLt) => self.cmplt(buf)?,
+                Some(Token::OpGt) => self.cmpgt(buf)?,
+                Some(Token::OpEq) => self.cmpeq(buf)?,
+                Some(Token::OpNeq) => self.cmpneq(buf)?,
+                Some(Token::LogAnd) => self.logand(buf)?,
+                Some(Token::LogOr) => self.logor(buf)?,
+                Some(Token::Print) => {
+                    self.lexer.next();
+                    self.require(Token::Semicolon)?;
+                    return Ok(Stmt::Print(buf).into());
+                }
+                _ => return Ok(buf.into()),
+            }
+        }
+    }
+
+    // Generate infix
+    gen_infix! {
+        addition => Add;
+        subtract => Subtract;
+        multiply => Multiply;
+        divide => Divide;
+        cmplt => Lt;
+        cmpgt => Gt;
+        cmpeq => Eq;
+        cmpneq => Neq;
+        logand => And;
+        logor => Or;
+    }
+
+    /// Ensure that input token is an expression
+    pub(super) fn parse_expr(&mut self, token: Option<Token>) -> ExprResult {
+        let token = token.ok_or(Error {
+            kind: ErrorKind::EndOfTokenStream,
+            position: self.lexer.span(),
+        })?;
+
+        match token {
+            Token::Boolean(b) => Ok(Expr::Literal(Value::Bool(b))),
+            Token::Integer(i) => Ok(Expr::Literal(Value::Int(i))),
+            Token::String(s) => Ok(Expr::Literal(Value::Str(if self.tdark {
+                s.replace("lang", "script")
+            } else {
+                s
+            }))),
+            Token::Aboolean(a) => Ok(Expr::Literal(Value::Abool(a))),
+            Token::Identifier(i) => Ok(Expr::Identifier(Iden(if self.tdark {
+                i.replace("lang", "script")
+            } else {
+                i
+            }))),
+            Token::Nul => Ok(Expr::Literal(Value::Nul)),
+            Token::LogNot => {
+                let next = self.lexer.next();
+                Ok(Expr::Not(Box::new(self.parse_expr(next)?)))
+            }
+            Token::LeftParenthesis => self.parse_paren(),
+            t => Err(self.unexpected_token(Some(t))),
+        }
+    }
+
+    /// Parse parenthesieted expression
+    fn parse_paren(&mut self) -> ExprResult {
+        let next = self.lexer.next();
+        let mut buf = self.parse_expr(next)?;
+        loop {
+            let next = self.lexer.peek().clone().ok_or(Error {
+                kind: ErrorKind::EndOfTokenStream,
+                position: self.lexer.span(),
+            })?;
+
+            buf = match Some(next) {
+                Some(Token::Addition) => self.addition(buf)?,
+                Some(Token::Subtract) => self.subtract(buf)?,
+                Some(Token::Multiply) => self.multiply(buf)?,
+                Some(Token::Divide) => self.divide(buf)?,
+                Some(Token::LeftParenthesis) => {
+                    return Err(Error {
+                        kind: ErrorKind::SyntaxError(
+                            "Function call isn't an expression!".to_owned(),
+                        ),
+                        position: self.lexer.span(),
+                    })
+                }
+                Some(Token::RightParenthesis) => {
+                    self.lexer.next();
+                    return Ok(buf);
+                }
+                _ => return Ok(buf),
+            };
+        }
+    }
+
+    /// Parse function call
+    fn fn_call(&mut self, token: Token) -> ParseResult {
+        let iden = if let Token::Identifier(i) = token {
+            Iden(i)
+        } else {
+            return Err(Error {
+                kind: ErrorKind::InvalidIdentifier,
+                position: self.lexer.span(),
+            });
+        };
+
+        self.lexer.next();
+        let mut args = Vec::new();
+        loop {
+            let next = self.lexer.next();
+
+            // No argument function
+            if matches!(next, Some(Token::RightParenthesis)) {
+                break;
+            }
+
+            args.push(self.parse_expr(next)?);
+            match self.lexer.next() {
+                Some(Token::RightParenthesis) => break,
+                Some(Token::Comma) => continue,
+                _ => return Err(self.unexpected_token(None)),
+            }
+        }
+        self.require(Token::Semicolon)?;
+        Ok(Stmt::FunctionCall { iden, args }.into())
+    }
+}

src/parser/utils.rs

@@ -1,8 +1,11 @@
 use crate::error::{Error, ErrorKind};
-use crate::tokens::Token;
+use crate::lexer::Token;
 use crate::variables::Abool;
 
-use super::{item::Expr, Parser};
+use super::{
+    item::{Iden, Item},
+    Parser,
+};
 
 pub fn abool2num(abool: Abool) -> i32 {
     match abool {
@@ -30,9 +33,14 @@ impl<'a> Parser<'a> {
         }
     }
 
-    pub(super) fn require_iden(&mut self) -> Result<String, Error> {
+    /// Require an identifier on next and return it
+    pub(super) fn require_iden(&mut self) -> Result<Iden, Error> {
         if let Some(Token::Identifier(id)) = self.lexer.next() {
-            Ok(id)
+            if self.tdark {
+                Ok(Iden(id.replace("lang", "script")))
+            } else {
+                Ok(Iden(id))
+            }
         } else {
             Err(Error {
                 kind: ErrorKind::InvalidIdentifier,
@@ -41,18 +49,23 @@ impl<'a> Parser<'a> {
         }
     }
 
+    /// Throw unexpected token error (optionally what was expected)
     pub(super) fn unexpected_token(&mut self, expected: Option<Token>) -> Error {
-        Error {
+        let error_msg = match expected {
-            kind: ErrorKind::SyntaxError(format!(
+            Some(s) => format!(
                 "Unexpected token: `{}` (required: `{:?}`)",
                 self.lexer.slice(),
-                expected
+                s
-            )),
+            ),
+            None => format!("Unexpected token: `{}`", self.lexer.slice(),),
+        };
+        Error {
+            kind: ErrorKind::SyntaxError(error_msg),
             position: self.lexer.span(),
         }
     }
 
-    pub(super) fn parse_body(&mut self) -> Result<Vec<Expr>, Error> {
+    pub(super) fn parse_body(&mut self) -> Result<Vec<Item>, Error> {
         let mut body = Vec::new();
         loop {
             let token = {
@@ -70,7 +83,7 @@ impl<'a> Parser<'a> {
             if token == Token::RightBrace {
                 break;
             }
-            body.push(self.parse_expr(Some(token))?);
+            body.push(self.parse_item(Some(token))?);
         }
         Ok(body)
     }

src/repl.rs

@@ -0,0 +1,41 @@
+use logos::Source;
+use rustyline::Editor;
+
+use crate::parser::Parser;
+
+pub fn repl() {
+    let mut rl = Editor::<()>::new();
+    loop {
+        let readline = rl.readline(":: ");
+        match readline {
+            Ok(line) => {
+                if &line == "exit" {
+                    println!("bye");
+                    break;
+                }
+                let mut parser = Parser::new(&line);
+                let ast = parser.init();
+                match ast {
+                    Ok(ast) => println!("{:?}", ast),
+                    Err(e) => {
+                        println!(
+                            "Error `{:?}` occured at span: {:?} = `{:?}`",
+                            e.kind,
+                            e.position.clone(),
+                            line.slice(e.position)
+                        );
+                    }
+                }
+            }
+            Err(rustyline::error::ReadlineError::Eof) => {
+                println!("bye");
+                break;
+            }
+            Err(rustyline::error::ReadlineError::Interrupted) => (),
+            Err(e) => {
+                println!("Error: {:?}", e);
+                break;
+            }
+        }
+    }
+}

src/variables.rs

@@ -7,9 +7,9 @@ pub enum Abool {
     Always = 1,
 }
 
-impl Into<bool> for Abool {
+impl From<Abool> for bool {
-    fn into(self) -> bool {
+    fn from(val: Abool) -> Self {
-        match self {
+        match val {
             Abool::Never => false,
             Abool::Always => true,
             Abool::Sometimes => rand::thread_rng().gen(),
@@ -17,12 +17,13 @@ impl Into<bool> for Abool {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum Value {
     Str(String),
     Int(i32),
     Bool(bool),
     Abool(Abool),
+    Nul,
 }
 
 #[derive(Debug)]