Merge pull request #10 from erindesu/master

Reimplemented parser

able-script-test/parse_test.able

@@ -1,10 +1,3 @@
-functio test() {
-    functio nested() {
-        var c = false;
-    }
-    var a = true;
-}
-
-functio another() {
-    var b = false;
+if (true) {
+    var a = 3;
 }

src/base_55.rs

@@ -122,3 +122,13 @@ pub fn num2char(number: i32) -> char {
         _ => ' ',
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn str_to_base55() {
+        let chrs: Vec<i32> = "AbleScript".chars().map(char2num).collect();
+        assert_eq!(chrs, &[-1, 2, 12, 5, -19, 3, 18, 9, 16, 20]);
+    }
+}

src/error.rs

@@ -8,12 +8,7 @@ pub struct Error {
 
 #[derive(Debug, Clone)]
 pub enum ErrorKind {
-    SyntaxError,
-}
-
-impl Error {
-    pub fn panic(&self, span: &str) {
-        println!("{:?} occured at {:?}", self.kind, self.position);
-        println!("    {}", &span);
-    }
+    SyntaxError(String),
+    EndOfTokenStream,
+    InvalidIdentifier,
 }

src/main.rs

@@ -32,7 +32,7 @@ fn main() {
 
             // Parse
             let mut parser = Parser::new(&source);
-            let ast = parser.parse();
+            let ast = parser.init();
             println!("{:#?}", ast);
         }
         None => {

src/parser/item.rs

@@ -1,6 +1,27 @@
+use crate::variables::Value;
+
+#[derive(Debug, Clone)]
+pub struct Iden(pub String);
+
 #[derive(Debug, Clone)]
 pub enum Expr {
-    VariableDeclaration { iden: String, init: Option<String> },
-    FunctionDeclaration { iden: String, body: Vec<Expr> },
-    BfFDeclaration { iden: String, code: String },
+    VariableDeclaration {
+        iden: String,
+        init: Option<Box<Expr>>,
+    },
+    FunctionDeclaration {
+        iden: String,
+        body: Vec<Expr>,
+    },
+    BfFDeclaration {
+        iden: String,
+        body: String,
+    },
+    If {
+        cond: Box<Expr>,
+        body: Vec<Expr>,
+    },
+
+    Literal(Value),
+    Melo(Iden),
 }

src/parser/mod.rs

@@ -3,14 +3,18 @@ mod utils;
 
 use item::Expr;
 
-use crate::error::{Error, ErrorKind};
-use crate::tokens::Token;
+use crate::{
+    error::{Error, ErrorKind},
+    variables::Value,
+};
+use crate::{parser::item::Iden, tokens::Token};
 
 use logos::Logos;
 
 /// Parser structure / state machine
 pub struct Parser<'a> {
     lexer: logos::Lexer<'a, Token>,
+    ast: Vec<Expr>,
 }
 
 impl<'a> Parser<'a> {
@@ -18,51 +22,80 @@ impl<'a> Parser<'a> {
     pub fn new(source: &'a str) -> Self {
         Self {
             lexer: Token::lexer(source),
+            ast: Vec::new(),
         }
     }
 
-    /// Start parsing Token Vector into Abstract Syntax Tree
-    pub fn parse(&mut self) -> Vec<Expr> {
-        let mut ast = vec![];
-        while let Some(token) = self.lexer.next() {
-            let expr = match token {
+    pub fn init(&mut self) -> Result<Vec<Expr>, Error> {
+        loop {
+            let token = self.lexer.next();
+            if token.is_none() {
+                return Ok(self.ast.clone());
+            };
+
+            let expr = self.parse_expr(token)?;
+            self.ast.push(expr);
+        }
+    }
+
+    fn parse_expr(&mut self, token: Option<Token>) -> Result<Expr, Error> {
+        if matches!(token, None) {
+            return Err(Error {
+                kind: ErrorKind::EndOfTokenStream,
+                position: self.lexer.span(),
+            });
+        }
+
+        let token = token.unwrap();
+        let start = self.lexer.span().start;
+
+        match token {
+            // Control flow
+            Token::If => self.if_cond(),
+
+            // Declarations
             Token::Variable => self.variable_declaration(),
             Token::Function => self.function_declaration(),
             Token::BfFunction => self.bff_declaration(),
-                Token::RightBrace => return ast,
-                _ => Err(Error {
-                    kind: ErrorKind::SyntaxError,
-                    position: 0..0,
-                }),
-            };
-            match expr {
-                Ok(o) => ast.push(o),
-                Err(e) => {
-                    e.panic(self.lexer.slice());
-                    break;
-                }
-            }
+
+            // 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)))
             }
 
-        ast
+            _ => Err(Error {
+                kind: ErrorKind::SyntaxError("Unexpected identifier".to_owned()),
+                position: start..self.lexer.span().end,
+            }),
+        }
     }
 
     /// Parse variable declaration
     ///
     /// `var [iden] = [literal];`
     fn variable_declaration(&mut self) -> Result<Expr, Error> {
-        let iden = self.require(Token::Identifier)?;
+        let iden = self.require_iden()?;
 
         let init = match self.lexer.next() {
             Some(Token::Semicolon) => None,
             Some(Token::Assignment) => {
-                let value = self.require(Token::Boolean)?; // TODO: Shouldn't be limited to boolean (pattern match?)
+                let value = self.lexer.next();
+                let value = self.parse_expr(value)?;
                 self.require(Token::Semicolon)?;
-                Some(value)
+                Some(Box::new(value))
             }
             _ => {
                 return Err(Error {
-                    kind: ErrorKind::SyntaxError,
+                    kind: ErrorKind::SyntaxError("Unexpected token".to_owned()),
                     position: self.lexer.span(),
                 })
             }
@@ -75,12 +108,13 @@ impl<'a> Parser<'a> {
     ///
     /// `functio [iden] ([expr], [expr]) { ... }
     fn function_declaration(&mut self) -> Result<Expr, Error> {
-        let iden = self.require(Token::Identifier)?;
+        let iden = self.require_iden()?;
         self.require(Token::LeftParenthesis)?;
-        // TODO: Arguments
         self.require(Token::RightParenthesis)?;
+
         self.require(Token::LeftBrace)?;
-        let body = self.parse();
+        // Parse function body
+        let body = self.parse_body()?;
 
         Ok(Expr::FunctionDeclaration { iden, body })
     }
@@ -89,10 +123,56 @@ impl<'a> Parser<'a> {
     ///
     /// `bff [iden] { ... }`
     fn bff_declaration(&mut self) -> Result<Expr, Error> {
-        let iden = self.require(Token::Identifier)?;
+        let iden = self.require_iden()?;
         self.require(Token::LeftBrace)?;
-        let code = self.require(Token::String)?; // <-- Nasty hack, but works
-        self.require(Token::RightBrace)?;
-        Ok(Expr::BfFDeclaration { iden, code })
+
+        let mut body = String::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_str(match token {
+                Token::OpGt
+                | Token::OpLt
+                | Token::Addition
+                | Token::Subtract
+                | Token::FullStop
+                | Token::Comma
+                | Token::LeftBracket
+                | Token::RightBracket => self.lexer.slice(),
+                Token::RightBrace => break,
+                _ => return Err(self.unexpected_token(None)),
+            });
+        }
+        Ok(Expr::BfFDeclaration { iden, body })
+    }
+
+    /// Parse If-expression
+    pub fn if_cond(&mut self) -> Result<Expr, Error> {
+        self.require(Token::LeftParenthesis)?;
+        let cond = self.lexer.next();
+        let cond = self.parse_expr(cond)?;
+        self.require(Token::RightParenthesis)?;
+
+        self.require(Token::LeftBrace)?;
+
+        let body = self.parse_body()?;
+
+        Ok(Expr::If {
+            cond: Box::new(cond),
+            body,
+        })
     }
 }

src/parser/utils.rs

@@ -2,7 +2,7 @@ use crate::error::{Error, ErrorKind};
 use crate::tokens::Token;
 use crate::variables::Abool;
 
-use super::Parser;
+use super::{item::Expr, Parser};
 
 pub fn abool2num(abool: Abool) -> i32 {
     match abool {
@@ -23,13 +23,55 @@ pub fn num2abool(number: i32) -> Abool {
 impl<'a> Parser<'a> {
     /// Require type of token as next and return it's value (sometimes irrelevant)
     pub(super) fn require(&mut self, with: Token) -> Result<String, Error> {
-        if self.lexer.next() == Some(with) {
+        if self.lexer.next() == Some(with.clone()) {
             Ok(self.lexer.slice().to_owned())
+        } else {
+            Err(self.unexpected_token(Some(with)))
+        }
+    }
+
+    pub(super) fn require_iden(&mut self) -> Result<String, Error> {
+        if let Some(Token::Identifier(id)) = self.lexer.next() {
+            Ok(id)
         } else {
             Err(Error {
-                kind: ErrorKind::SyntaxError,
+                kind: ErrorKind::InvalidIdentifier,
                 position: self.lexer.span(),
             })
         }
     }
+
+    pub(super) fn unexpected_token(&mut self, expected: Option<Token>) -> Error {
+        Error {
+            kind: ErrorKind::SyntaxError(format!(
+                "Unexpected token: `{}` (required: `{:?}`)",
+                self.lexer.slice(),
+                expected
+            )),
+            position: self.lexer.span(),
+        }
+    }
+
+    pub(super) fn parse_body(&mut self) -> Result<Vec<Expr>, Error> {
+        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_expr(Some(token))?);
+        }
+        Ok(body)
+    }
 }

src/tokens.rs

@@ -1,72 +1,9 @@
-use logos::Logos;
+use logos::{Lexer, Logos};
 
-#[derive(Logos, Debug, PartialEq)]
+use crate::variables::Abool;
+
+#[derive(Logos, Debug, PartialEq, Clone)]
 pub enum Token {
-    // Literals
-    /// True, False
-    #[regex("true|false")]
-    Boolean,
-
-    /// Always, Sometimes, Never
-    #[regex("always|sometimes|never")]
-    Aboolean,
-
-    /// String
-    #[regex("\"(\\.|[^\"])*\"")]
-    String,
-
-    /// Integer
-    #[regex(r"[0-9]+")]
-    Integer,
-
-    /// A C-complaint identifier
-    #[regex(r"[a-zA-Z_][a-zA-Z_0-9]*")]
-    Identifier,
-
-    #[token("(")]
-    LeftParenthesis,
-
-    #[token(")")]
-    RightParenthesis,
-
-    #[token("[")]
-    LeftBracket,
-
-    #[token("]")]
-    RightBracket,
-
-    #[token("{")]
-    LeftBrace,
-
-    #[token("}")]
-    RightBrace,
-
-    #[token(";")]
-    Semicolon,
-
-    #[regex(r"#.*")]
-    Comment,
-
-    // Operators
-    #[token("-")]
-    Subtract,
-
-    #[token("+")]
-    Addition,
-
-    #[token("*")]
-    Multiply,
-
-    #[token("/")]
-    Divide,
-
-    #[token("=")]
-    Assignment,
-
-    /// Base52 based character ('a')
-    #[token("'.*'")]
-    Char,
-
     #[token("functio")]
     Function,
 
@@ -99,7 +36,152 @@ pub enum Token {
     #[token("loop")]
     Loop,
 
+    // Literals
+    /// True, False
+    #[regex("true|false", get_bool)]
+    Boolean(bool),
+
+    /// Always, Sometimes, Never
+    #[regex("always|sometimes|never", get_abool)]
+    Aboolean(Abool),
+
+    /// String
+    #[regex("\"(\\.|[^\"])*\"", get_string)]
+    String(String),
+
+    /// Integer
+    #[regex(r"[0-9]+", get_int)]
+    Integer(i32),
+
+    /// A C-complaint identifier
+    #[regex(r"[a-zA-Z_][a-zA-Z_0-9]*", get_iden)]
+    Identifier(String),
+
+    #[token("(")]
+    LeftParenthesis,
+
+    #[token(")")]
+    RightParenthesis,
+
+    #[token("[")]
+    LeftBracket,
+
+    #[token("]")]
+    RightBracket,
+
+    #[token("{")]
+    LeftBrace,
+
+    #[token("}")]
+    RightBrace,
+
+    #[token(";")]
+    Semicolon,
+
+    #[token(".")]
+    FullStop,
+
+    #[token(",")]
+    Comma,
+
+    #[regex(r"#.*")]
+    Comment,
+
+    // Operators
+    #[token("-")]
+    Subtract,
+
+    #[token("+")]
+    Addition,
+
+    #[token("*")]
+    Multiply,
+
+    #[token("/")]
+    Divide,
+
+    #[token("=")]
+    Assignment,
+
+    // Logical operators
+    #[token("<")]
+    OpLt,
+
+    #[token(">")]
+    OpGt,
+
+    #[token("==")]
+    OpEq,
+
+    #[token("!=")]
+    OpNeq,
+
+    /// Base52 based character ('a')
+    #[token("'.*'")]
+    Char,
+
     #[regex(r"[ \t\n\f]+", logos::skip)]
     #[error]
     Error,
 }
+
+fn get_bool(lexer: &mut Lexer<Token>) -> Option<bool> {
+    lexer.slice().parse().ok()
+}
+
+fn get_int(lexer: &mut Lexer<Token>) -> Option<i32> {
+    lexer.slice().parse().ok()
+}
+
+fn get_string(lexer: &mut Lexer<Token>) -> String {
+    lexer.slice().trim_matches('"').to_owned()
+}
+
+fn get_abool(lexer: &mut Lexer<Token>) -> Option<Abool> {
+    match lexer.slice() {
+        "always" => Some(Abool::Always),
+        "sometimes" => Some(Abool::Sometimes),
+        "never" => Some(Abool::Never),
+        _ => None,
+    }
+}
+
+fn get_iden(lexer: &mut Lexer<Token>) -> String {
+    lexer.slice().to_owned()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Token;
+    use super::Token::*;
+    use logos::Logos;
+
+    #[test]
+    fn simple_fn() {
+        let code = "functio test() { var a = 3; if a == 3 { a print } }";
+        let expected = &[
+            Function,
+            Identifier("test".to_owned()),
+            LeftParenthesis,
+            RightParenthesis,
+            LeftBrace,
+            Variable,
+            Identifier("a".to_owned()),
+            Assignment,
+            Integer(3),
+            Semicolon,
+            If,
+            Identifier("a".to_owned()),
+            OpEq,
+            Integer(3),
+            LeftBrace,
+            Identifier("a".to_owned()),
+            Print,
+            RightBrace,
+            RightBrace,
+        ];
+        let lexer = Token::lexer(code);
+        let result: Vec<Token> = lexer.collect();
+        assert_eq!(result, expected);
+    }
+}

src/variables.rs

@@ -1,5 +1,4 @@
 use rand::Rng;
-use std::collections::HashMap;
 
 #[derive(Debug, Clone, PartialEq)]
 pub enum Abool {
@@ -31,20 +30,3 @@ pub struct Variable {
     melo: bool,
     value: Value,
 }
-pub fn test() {
-    let mut map = HashMap::new();
-    let a = Variable {
-        melo: false,
-        value: Value::Str("1".to_string()),
-    };
-    let b = Variable {
-        melo: false,
-        value: Value::Int(2),
-    };
-    map.insert("a", a);
-    map.insert("b", b);
-
-    for (key, value) in &map {
-        println!("{}: {:?}", key, value);
-    }
-}