Added function/variable parsing

- Added block support
- TODO: Tidy it up

able-script-test/parse_test.able

@@ -1,2 +1,10 @@
-var hello = true;
-var test;
+functio test() {
+    functio nested() {
+        var c = false;
+    }
+    var a = true;
+}
+
+functio another() {
+    var b = false;
+}

src/error.rs

@@ -0,0 +1,19 @@
+use std::ops::Range;
+
+#[derive(Debug, Clone)]
+pub struct Error {
+    pub kind: ErrorKind,
+    pub position: Range<usize>,
+}
+
+#[derive(Debug, Clone)]
+pub enum ErrorKind {
+    SyntaxError,
+}
+
+impl Error {
+    pub fn panic(&self, span: &str) {
+        println!("{:?} occured at {:?}", self.kind, self.position);
+        println!("    {}", &span);
+    }
+}

src/main.rs

@@ -1,6 +1,7 @@
 #![forbid(unsafe_code)]
 
 mod base_55;
+mod error;
 mod parser;
 mod tokens;
 mod variables;

src/parser/item.rs

@@ -1,4 +1,6 @@
 #[derive(Debug, Clone)]
 pub enum Expr {
-    DeclareVariable { iden: String, init: Option<String> },
+    VariableDeclaration { iden: String, init: Option<String> },
+    FunctionDeclaration { iden: String, body: Vec<Expr> },
+    BfFDeclaration { iden: String, code: String },
 }

src/parser/mod.rs

@@ -3,8 +3,11 @@ mod utils;
 
 use item::Expr;
 
-use crate::tokens::Token;
 use crate::variables::Value;
+use crate::{
+    error::{Error, ErrorKind},
+    tokens::Token,
+};
 
 use logos::Logos;
 
@@ -18,7 +21,6 @@ pub enum ParseError {
 /// Parser structure / state machine
 pub struct Parser<'a> {
     lexer: logos::Lexer<'a, Token>,
-    ast: Vec<Expr>,
 }
 
 impl<'a> Parser<'a> {
@@ -26,31 +28,39 @@ impl<'a> Parser<'a> {
     pub fn new(source: &'a str) -> Self {
         Self {
             lexer: Token::lexer(source),
-            ast: vec![],
         }
     }
 
     /// 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 {
-                Token::Variable => self.variable(),
-                tok => {
-                    // TODO: Better error handling
-                    println!("Parse error");
+                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;
                 }
-            };
-           self.ast.push(expr.unwrap());
+            }
         }
 
-        self.ast.clone()
+        ast
     }
 
     /// Parse variable declaration
     ///
     /// `var [iden] = [literal];`
-    fn variable(&mut self) -> Result<Expr, ParseError> {
+    fn variable_declaration(&mut self) -> Result<Expr, Error> {
         let iden = self.require(Token::Identifier)?;
 
         let init = match self.lexer.next() {
@@ -60,9 +70,39 @@ impl<'a> Parser<'a> {
                 self.require(Token::Semicolon)?;
                 Some(value)
             }
-            _ => return Err(ParseError::UnexpectedToken),
+            _ => {
+                return Err(Error {
+                    kind: ErrorKind::SyntaxError,
+                    position: self.lexer.span(),
+                })
+            }
         };
 
-        Ok(Expr::DeclareVariable { iden, init })
+        Ok(Expr::VariableDeclaration { iden, init })
+    }
+
+    /// Declare function
+    ///
+    /// `functio [iden] ([expr], [expr]) { ... }
+    fn function_declaration(&mut self) -> Result<Expr, Error> {
+        let iden = self.require(Token::Identifier)?;
+        self.require(Token::LeftParenthesis)?;
+        // TODO: Arguments
+        self.require(Token::RightParenthesis)?;
+        self.require(Token::LeftBrace)?;
+        let body = self.parse();
+
+        Ok(Expr::FunctionDeclaration { iden, body })
+    }
+
+    /// Declare BF FFI Function
+    ///
+    /// `bff [iden] { ... }`
+    fn bff_declaration(&mut self) -> Result<Expr, Error> {
+        let iden = self.require(Token::Identifier)?;
+        self.require(Token::LeftBrace)?;
+        let code = self.require(Token::String)?; // <-- Nasty hack, but works
+        self.require(Token::RightBrace)?;
+        Ok(Expr::BfFDeclaration { iden, code })
     }
 }

src/parser/utils.rs

@@ -1,4 +1,7 @@
-use crate::tokens::{Abool, Token};
+use crate::{
+    error::{Error, ErrorKind},
+    tokens::{Abool, Token},
+};
 
 use super::{ParseError, Parser};
 
@@ -20,11 +23,14 @@ 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, ParseError> {
+    pub(super) fn require(&mut self, with: Token) -> Result<String, Error> {
         if self.lexer.next() == Some(with) {
             Ok(self.lexer.slice().to_owned())
         } else {
-            Err(ParseError::UnexpectedToken)
+            Err(Error {
+                kind: ErrorKind::SyntaxError,
+                position: self.lexer.span(),
+            })
         }
     }
 }

src/tokens.rs

@@ -2,6 +2,23 @@ use logos::Logos;
 
 #[derive(Logos, Debug, PartialEq)]
 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,
@@ -61,22 +78,6 @@ pub enum Token {
     #[token("var")]
     Variable,
 
-    /// True, False
-    #[regex("true|false")]
-    Boolean,
-
-    /// Always, Sometimes, Never
-    #[regex("always|sometimes|never")]
-    Aboolean,
-
-    /// String
-    #[regex("\"(\\.|[^\"])*\"")]
-    String,
-
-    /// Integer
-    #[regex(r"[0-9]+")]
-    Integer,
-
     /// Prints the preceding things
     #[token("print")]
     Print,