Added parsing of conditionals

able-script-test/parse_test.able

@@ -1 +1,3 @@
-bff a {+++<<>>>[]]]][[]]}
+if (true) {
+    var a = 3;
+}

src/base_55.rs

@@ -126,8 +126,9 @@ pub fn num2char(number: i32) -> char {
 #[cfg(test)]
 mod tests {
     use super::*;
-    #[test] fn str_to_base55() {
+    #[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

@@ -11,4 +11,4 @@ pub enum ErrorKind {
     SyntaxError(String),
     EndOfTokenStream,
     InvalidIdentifier,
-}
+}

src/parser/item.rs

@@ -1,5 +1,8 @@
 use crate::variables::Value;
 
+#[derive(Debug, Clone)]
+pub struct Iden(pub String);
+
 #[derive(Debug, Clone)]
 pub enum Expr {
     VariableDeclaration {
@@ -14,5 +17,11 @@ pub enum Expr {
         iden: String,
         body: String,
     },
+    If {
+        cond: Box<Expr>,
+        body: Vec<Expr>,
+    },
+
     Literal(Value),
+    Melo(Iden),
 }

src/parser/mod.rs

@@ -3,11 +3,11 @@ mod utils;
 
 use item::Expr;
 
-use crate::tokens::Token;
 use crate::{
     error::{Error, ErrorKind},
     variables::Value,
 };
+use crate::{parser::item::Iden, tokens::Token};
 
 use logos::Logos;
 
@@ -50,13 +50,28 @@ impl<'a> Parser<'a> {
         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(),
+
+            // 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)))
+            }
+
             _ => Err(Error {
                 kind: ErrorKind::SyntaxError("Unexpected identifier".to_owned()),
                 position: start..self.lexer.span().end,
@@ -99,25 +114,7 @@ impl<'a> Parser<'a> {
 
         self.require(Token::LeftBrace)?;
         // Parse function body
-        let mut body = Vec::new();
+        let body = self.parse_body()?;
-        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(Expr::FunctionDeclaration { iden, body })
     }
@@ -161,4 +158,21 @@ impl<'a> Parser<'a> {
         }
         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 {
@@ -51,4 +51,27 @@ impl<'a> Parser<'a> {
             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

@@ -4,6 +4,38 @@ use crate::variables::Abool;
 
 #[derive(Logos, Debug, PartialEq, Clone)]
 pub enum Token {
+    #[token("functio")]
+    Function,
+
+    /// Brain fuck FFI
+    #[token("bff")]
+    BfFunction,
+
+    /// Variable bro
+    #[token("var")]
+    Variable,
+
+    /// Prints the preceding things
+    #[token("print")]
+    Print,
+
+    /// Ban the following variable from ever being used again
+    #[token("melo")]
+    Melo,
+
+    #[token("T-Dark")]
+    TDark,
+
+    // Expressions
+    #[token("if")]
+    If,
+
+    #[token("else")]
+    Else,
+
+    #[token("loop")]
+    Loop,
+
     // Literals
     /// True, False
     #[regex("true|false", get_bool)]
@@ -88,38 +120,6 @@ pub enum Token {
     #[token("'.*'")]
     Char,
 
-    #[token("functio")]
-    Function,
-
-    /// Brain fuck FFI
-    #[token("bff")]
-    BfFunction,
-
-    /// Variable bro
-    #[token("var")]
-    Variable,
-
-    /// Prints the preceding things
-    #[token("print")]
-    Print,
-
-    /// Ban the following variable from ever being used again
-    #[token("melo")]
-    Melo,
-
-    #[token("T-Dark")]
-    TDark,
-
-    // Expressions
-    #[token("if")]
-    If,
-
-    #[token("else")]
-    Else,
-
-    #[token("loop")]
-    Loop,
-
     #[regex(r"[ \t\n\f]+", logos::skip)]
     #[error]
     Error,
@@ -184,4 +184,4 @@ mod tests {
         let result: Vec<Token> = lexer.collect();
         assert_eq!(result, expected);
     }
-}
+}

src/variables.rs

@@ -29,4 +29,4 @@ pub enum Value {
 pub struct Variable {
     melo: bool,
     value: Value,
-}
+}