Merge remote-tracking branch 'refs/remotes/origin/compiler' into compiler

compiler/src/parser.rs

@@ -1,4 +1,4 @@
-use crate::expect_type;
+use crate::expect_tt;
 use crate::lexer::Token;
 
 pub struct Parser {
@@ -10,7 +10,7 @@ pub struct Parser {
 impl Parser {
     pub fn new(tokens: Vec<Token>) -> Self {
         Self {
-            ast: Node::Scope {
+            ast: Node::Block {
                 children: Vec::new(),
             },
             idx: 0,
@@ -19,13 +19,17 @@ impl Parser {
     }
 
     pub fn parse(&mut self) -> Result<Node, CompileError> {
+        self.parse_block()
+    }
+
+    fn parse_block(&mut self) -> Result<Node, CompileError> {
         let mut statements = Vec::new();
 
-        while let Some(_) = self.peek_next() {
+        while self.peek_next().is_ok() {
             statements.push(self.parse_statement()?);
         }
 
-        Ok(Node::Scope {
+        Ok(Node::Block {
             children: statements,
         })
     }
@@ -35,11 +39,11 @@ impl Parser {
         let left = if let Ok(typed_var) = self.parse_typed_var() {
             Box::new(typed_var)
         } else {
-            let tok = expect_type!(self.next()?, Identifier)?;
+            let tok = expect_tt!(self.next()?, Identifier)?;
             Box::new(Node::Terminal { value: tok })
         };
 
-        let _ = expect_type!(self.next()?, Assign)?;
+        let _ = expect_tt!(self.next()?, Assign)?;
 
         let right = Box::new(self.parse_expression()?);
 
@@ -47,17 +51,144 @@ impl Parser {
     }
 
     fn parse_typed_var(&mut self) -> Result<Node, CompileError> {
-        let name = expect_type!(self.next()?, Identifier)?;
+        let name = expect_tt!(self.next()?, Identifier)?;
-        let _ = expect_type!(self.next()?, Colon)?;
+        let _ = expect_tt!(self.next()?, Colon)?;
-        let type_ = expect_type!(self.next()?, Identifier)?;
+        let type_ = expect_tt!(self.next()?, Identifier)?;
 
         Ok(Node::TypedVar { name, type_ })
     }
 
     fn parse_expression(&mut self) -> Result<Node, CompileError> {
+        if expect_tt!(self.peek_next()?, Pipe).is_ok() {
+            return self.parse_func();
+        }
+
+        if expect_tt!(self.peek_next()?, If).is_ok() {
+            return self.parse_if();
+        }
+
+        if expect_tt!(self.peek_next()?, Loop).is_ok() {
+            return self.parse_loop();
+        }
+
+        if expect_tt!(self.peek_next()?, Identifier, String, Number).is_ok() {
+            let left = Node::Terminal {
+                value: self.next()?,
+            };
+
+            if expect_tt!(
+                self.next()?,
+                Plus,
+                Minus,
+                Star,
+                Slash,
+                EqualEqual,
+                BangEqual,
+                Less,
+                LessEqual,
+                Greater,
+                GreaterEqual
+            )
+            .is_err()
+            {
+                return Ok(left);
+            }
+
+            let operator = self.next()?;
+            let right = Box::new(self.parse_expression()?);
+
+            return Ok(Node::BinaryOp {
+                left: Box::new(left),
+                op: operator,
+                right,
+            });
+        }
+
         Err(CompileError::Generic)
     }
 
+    fn parse_func(&mut self) -> Result<Node, CompileError> {
+        // left arg delimiter
+        let _ = expect_tt!(self.next()?, Pipe)?;
+
+        // parse args
+        let mut args = Vec::new();
+
+        while expect_tt!(self.peek_next()?, Identifier).is_ok() {
+            // add a typed var
+            let arg = self.parse_typed_var()?;
+            args.push(arg);
+        }
+
+        // right arg delimiter
+        let _ = expect_tt!(self.next()?, Pipe)?;
+
+        // ensure we have an open brace
+        let _ = expect_tt!(self.next()?, LeftBrace)?;
+
+        // parse the body
+        let body = Box::new(self.parse_block()?);
+
+        // ensure we have a close brace
+        let _ = expect_tt!(self.next()?, RightBrace)?;
+
+        Ok(Node::FunctionDef { params: args, body })
+    }
+
+    fn parse_loop(&mut self) -> Result<Node, CompileError> {
+        let _ = expect_tt!(self.next()?, Loop)?;
+
+        // ensure we have an open brace
+        let _ = expect_tt!(self.next()?, LeftBrace)?;
+
+        // parse the body
+        let body = Box::new(self.parse_block()?);
+
+        // ensure we have a close brace
+        let _ = expect_tt!(self.next()?, RightBrace)?;
+
+        Ok(Node::Loop { body })
+    }
+
+    fn parse_if(&mut self) -> Result<Node, CompileError> {
+        let _ = expect_tt!(self.next()?, If)?;
+
+        // parse condition (expr)
+        let condition = Box::new(self.parse_expression()?);
+
+        // ensure we have an open brace
+        let _ = expect_tt!(self.next()?, LeftBrace)?;
+
+        // parse the "then" branch (expr/statement)
+        let then_branch = Box::new(self.parse_expression()?);
+
+        // ensure we have a close brace
+        let _ = expect_tt!(self.next()?, RightBrace)?;
+
+        // if there is an else branch, we include it in the statement
+        let else_branch = self.parse_else()?.map(Box::new);
+
+        Ok(Node::If {
+            condition,
+            then_branch,
+            else_branch,
+        })
+    }
+
+    fn parse_else(&mut self) -> Result<Option<Node>, CompileError> {
+        // if there is no else branch, return None.
+        if expect_tt!(self.peek_next()?, Else).is_err() {
+            return Ok(None);
+        }
+        let _ = self.next()?;
+
+        if expect_tt!(self.peek_next()?, If).is_ok() {
+            Ok(Some(self.parse_if()?))
+        } else {
+            Ok(Some(self.parse_expression()?))
+        }
+    }
+
     fn next(&mut self) -> Result<Token, CompileError> {
         if self.idx >= self.tokens.len() {
             return Err(CompileError::UnexpectedEOF);
@@ -69,53 +200,54 @@ impl Parser {
         Ok(token)
     }
 
-    fn peek_next(&mut self) -> Option<Token> {
+    fn peek_next(&mut self) -> Result<Token, CompileError> {
         if self.idx >= self.tokens.len() {
-            return None;
+            return Err(CompileError::UnexpectedEOF);
         }
 
-        Some(self.tokens[self.idx].clone())
+        Ok(self.tokens[self.idx].clone())
     }
 }
-
 #[derive(Debug, Clone, PartialEq)]
 pub enum Node {
-    Scope {
+    /// A scope, which is a list of child nodes that are evaluated in order.
-        children: Vec<Node>,
+    Block { children: Vec<Node> },
-    },
+
-    Terminal {
+    /// A leaf node with a value.
-        value: Token,
+    Terminal { value: Token },
-    },
+
-    UnaryOp {
+    /// A unary operator with a right operand.
-        op: Token,
+    UnaryOp { op: Token, right: Box<Node> },
-        right: Box<Node>,
+
-    },
+    /// A binary operator with a left and right operand.
     BinaryOp {
         left: Box<Node>,
         op: Token,
         right: Box<Node>,
     },
-    Statement {
+
-        left: Box<Node>,
+    /// A statement, consisting of a value to assign to, and an expression.
-        right: Box<Node>,
+    Statement { left: Box<Node>, right: Box<Node> },
-    },
+
+    /// An if expression, which evaluates to either the then branch or the else branch.
     If {
         condition: Box<Node>,
         then_branch: Box<Node>,
         else_branch: Option<Box<Node>>,
     },
-    FunctionDef {
+
-        params: Vec<Node>,
+    /// A loop expression, which evaluates to the last value of the loop.
-        body: Box<Node>,
+    /// a loop can be exited with the break keyword.
-    },
+    Loop { body: Box<Node> },
-    TypedVar {
+
-        name: Token,
+    /// A function definition. ``` | param: type .. | -> ret_type { body }```
-        type_: Token,
+    FunctionDef { params: Vec<Node>, body: Box<Node> },
-    },
+
-    TypeDef {
+    /// A typed variable definition: ```val: Type```
-        name: Token,
+    TypedVar { name: Token, type_: Token },
-        fields: Vec<Node>,
+
-    },
+    /// A type definition, which is a list of fields. ```type MyType { field: Type }```
+    TypeDef { name: Token, fields: Vec<Node> },
 }
 
 #[derive(Debug)]
@@ -126,16 +258,44 @@ pub enum CompileError {
 }
 
 #[macro_export]
-macro_rules! expect_type {
+macro_rules! expect_tt {
     ($token:expr, $($variant:ident),+) => {{
-        match $token.tt() {
+        let tt = $token.tt().to_string();
+
+        println!("CASE");
+        println!("TOK {:?}", $token);
+        println!("TT {}", tt);
+
+        let mut vs = String::new();
+        $(
+            let s = stringify!($variant);
+            vs.push_str(s);
+            vs.push_str("|");
+        )+
+
+        match tt.as_str() {
             $(
                 stringify!($variant) => Ok($token.clone()),
             )+
             _ => {
-                // return an expected token error
+                println!("EXPECTED!! {} [{}]", tt, vs);
                 let expected = format!("[{}]", vec![$(stringify!($variant)),+].join(" | "));
-
+                Err(CompileError::ExpectedToken {
+                    expected,
+                    found: $token.clone(),
+                })
+            }
+        }
+    }};
+}
+
+#[macro_export]
+macro_rules! expect_value {
+    ($token:expr, $variant:expr) => {{
+        match $token {
+            $variant(x) => Ok(x),
+            _ => {
+                let expected = format!("[{}]")
                 Err(CompileError::ExpectedToken {
                     expected,
                     found: $token.clone(),