remove old parser, work towards rewritten parser

examples/hello.v

@@ -0,0 +1,3 @@
+fn main() {
+	println("hello world!");
+}

src/ast.zig

@@ -1,103 +1,25 @@
+const std = @import("std");
 const tokens = @import("tokens.zig");
 const Token = tokens.Token;
 
-pub const ExprType = enum {
+pub const NodeList = std.ArrayList(*Node);
-    Unary,
+
-    Binary,
+pub const NodeType = enum {
-    Grouping,
+    Root,
-    Number,
+    FnDecl,
-    Bool,
-    Nil,
-    String,
 };
 
-pub const Expr = union(ExprType) {
+pub const FnDecl = struct {
-    Unary: UnaryExpr,
+    func_name: []const u8,
-    Binary: BinaryExpr,
-    Grouping: Grouping,
-    Number: Number,
-    Bool: Bool,
-    Nil: Nil,
-    String: String,
 };
 
-pub const UnaryExpr = struct {
+pub const Node = union(NodeType) {
-    operator: Token,
+    Root: NodeList,
-    right: *Expr,
+    FnDecl: FnDecl,
 };
 
-pub fn mkUnary(operator: Token, right: *Expr) Expr {
+pub fn mkRoot(allocator: *std.mem.Allocator) !*Node {
-    return Expr{
+    var node = try allocator.create(Node);
-        .Unary = UnaryExpr{
+    node.* = Node{ .Root = NodeList.init(allocator) };
-            .operator = operator,
+    return node;
-            .right = right,
-        },
-    };
 }
-
-pub const BinaryExpr = struct {
-    left: *Expr,
-    operator: Token,
-    right: *Expr,
-};
-
-pub fn mkBinary(left: *Expr, operator: Token, right: *Expr) Expr {
-    return Expr{
-        .Binary = BinaryExpr{
-            .left = left,
-            .operator = operator,
-            .right = right,
-        },
-    };
-}
-
-pub const Grouping = struct {
-    expression: *Expr,
-};
-
-pub fn mkGrouping(expression: *Expr) Expr {
-    return Expr{
-        .Grouping = Grouping{
-            .expression = expression,
-        },
-    };
-}
-
-/// Represents the default number literals in V.
-pub const NumberType = enum {
-    Integer32,
-    Integer64,
-    Unsigned32,
-    Unsigned64,
-    Float32,
-    Float64,
-};
-
-/// "translation" of V number types to Zig number types for nicer
-/// representation.
-pub const Number = union(NumberType) {
-    Integer32: i32,
-    Integer64: i64,
-    Unsigned32: u32,
-    Unsigned64: u64,
-    Float32: f32,
-    Float64: f64,
-};
-
-pub fn mkNum(comptime T: type, num: T) Expr {
-    var expr = switch (T) {
-        i32 => Expr{ .Number = Number{ .Integer32 = num } },
-        i64 => Expr{ .Number = Number{ .Integer64 = num } },
-        u32 => Expr{ .Number = Number{ .Unsigned32 = num } },
-        u64 => Expr{ .Number = Number{ .Unsigned64 = num } },
-        f32 => Expr{ .Number = Number{ .Float32 = num } },
-        f64 => Expr{ .Number = Number{ .Float64 = num } },
-        else => unreachable,
-    };
-
-    return expr;
-}
-
-pub const Bool = bool;
-pub const Nil = void;
-pub const String = []u8;

src/parser.zig

@@ -10,8 +10,7 @@ const Scanner = scanners.Scanner;
 const Token = tokens.Token;
 const TokenType = tokens.TokenType;
 const Result = main.Result;
-
+const Node = ast.Node;
-const Expr = ast.Expr;
 
 pub const Parser = struct {
     allocator: *Allocator,
@@ -24,7 +23,7 @@ pub const Parser = struct {
         return Parser{ .allocator = allocator, .scanner = scanner };
     }
 
-    fn doError(self: *Parser, comptime fmt: []const u8, args: ...) !void {
+    fn doError(self: *Parser, comptime fmt: []const u8, args: ...) Result!void {
         std.debug.warn("parser error at line {}\n\t", self.scanner.line);
         std.debug.warn(fmt, args);
         std.debug.warn("\n");
@@ -50,20 +49,6 @@ pub const Parser = struct {
         return Result.CompileError;
     }
 
-    fn synchronize(self: *Parser) void {
-        _ = self.advance();
-        while (!self.isAtEnd()) {
-            if (self.previous().ttype == .Semicolon) return;
-
-            switch (self.peek().ttype) {
-                .Struct, .Fn, .For, .If, .Return => return,
-                else => {},
-            }
-
-            _ = self.advance();
-        }
-    }
-
     fn isAtEnd(self: *Parser) bool {
         return self.peek().ttype == .EOF;
     }
@@ -105,150 +90,50 @@ pub const Parser = struct {
         return Result.CompileError;
     }
 
-    fn equality(self: *Parser) !Expr {
+    fn mkFnDecl(self: *Parser, name: []const u8) !*ast.Node {
-        var expr = try self.comparison();
+        var node = try self.allocator.create(Node.FnDecl);
-
+        node.* = Node.FnDecl{ .name = name };
-        while (self.match(&[_]TokenType{ TokenType.BangEqual, TokenType.EqualEqual })) {
+        return node;
-            var operator = self.previous();
-            var right = try self.comparison();
-
-            expr = ast.mkBinary(&expr, operator, &right);
     }
 
-        return expr;
+    fn functionDecl(self: *Parser) !*ast.Node {
+        // get the name
+        var name = try self.consume(.Identifier, "expected function name");
+        return try self.mkFnDecl(name);
     }
 
-    fn comparison(self: *Parser) !Expr {
+    fn processToken(self: *Parser, token: Token) Result!ast.Node {
-        var expr = try self.addition();
+        switch (token.ttype) {
-
+            //.Fn => try self.functionDecl(),
-        while (self.match(&[_]TokenType{
+            else => blk: {
-            TokenType.Greater,
+                try self.doError("TODO handle {}\n", token.ttype);
-            TokenType.GreaterEqual,
-            TokenType.Less,
-            TokenType.LessEqual,
-        })) {
-            var operator = self.previous();
-            var right = try self.addition();
-            expr = ast.mkBinary(&expr, operator, &right);
-        }
-
-        return expr;
-    }
-
-    fn addition(self: *Parser) !Expr {
-        var expr = try self.multiplication();
-
-        while (self.match(&[_]TokenType{ TokenType.Minus, TokenType.Plus })) {
-            var operator = self.previous();
-            var right = try self.multiplication();
-            expr = ast.mkBinary(&expr, operator, &right);
-        }
-
-        return expr;
-    }
-
-    fn multiplication(self: *Parser) anyerror!Expr {
-        var expr = try self.unary();
-
-        while (self.match(&[_]TokenType{ TokenType.Slash, TokenType.Star })) {
-            var operator = self.previous();
-            var right = try self.unary();
-            expr = ast.mkBinary(&expr, operator, &right);
-        }
-
-        return expr;
-    }
-
-    fn unary(self: *Parser) anyerror!Expr {
-        if (self.match(&[_]TokenType{ TokenType.Bang, TokenType.Minus })) {
-            var operator = self.previous();
-            var right = try self.unary();
-            return ast.mkUnary(operator, &right);
-        }
-
-        return try self.primary();
-    }
-
-    fn doInt(self: *Parser) !Expr {
-        var token = self.previous();
-
-        // try to parse it as an i32 first, if that fails, do i64.
-
-        var num_32 = std.fmt.parseInt(i32, token.lexeme, 10) catch |pi_err| {
-            if (pi_err == error.Overflow) {
-                var num_64 = std.fmt.parseInt(i64, token.lexeme, 10) catch |pi_err2| {
-                    if (pi_err2 == error.Overflow) {
-                        try self.tokenError(token, "Failed to parse number: overflow");
                 return Result.CompileError;
-                    } else {
+            },
-                        return pi_err2;
         }
-                };
-
-                return ast.mkNum(i64, num_64);
-            } else {
-                return pi_err;
-            }
-        };
-
-        return ast.mkNum(i32, num_32);
     }
 
-    fn primary(self: *Parser) !Expr {
+    pub fn parse(self: *Parser) !*ast.Node {
-        if (self.matchSingle(TokenType.False)) return ast.Expr{ .Bool = false };
-        if (self.matchSingle(TokenType.True)) return ast.Expr{ .Bool = true };
-        if (self.matchSingle(TokenType.None)) return ast.Expr{ .Nil = {} };
-
-        if (self.matchSingle(TokenType.Integer)) {
-            return try self.doInt();
-        }
-
-        if (self.matchSingle(TokenType.String)) {
-            var lexeme = self.previous().lexeme;
-            var slice = try self.allocator.alloc(u8, lexeme.len);
-            std.mem.copy(u8, slice, lexeme);
-
-            return ast.Expr{ .String = slice };
-        }
-
-        if (self.matchSingle(TokenType.LeftParen)) {
-            var expr = try self.expression();
-            _ = try self.consume(.RightParen, "Expect ')' after expression");
-
-            return ast.mkGrouping(&expr);
-        }
-
-        try self.tokenError(self.peek(), "Expect expression");
-        return Result.CompileError;
-    }
-
-    fn expression(self: *Parser) !Expr {
-        return try self.equality();
-    }
-
-    pub fn parse(self: *Parser) !?*Expr {
         self.tokens = try self.allocator.alloc(Token, 0);
         var i: usize = 0;
+        var root = try ast.mkRoot(self.allocator);
 
         while (true) {
             var tok_opt = try self.scanner.nextToken();
+
             if (tok_opt) |token| {
                 self.tokens = try self.allocator.realloc(self.tokens, i + 1);
                 self.tokens[i] = token;
                 i += 1;
 
                 if (token.ttype == .EOF) break;
+
+                var node = try self.processToken(token);
+                try root.Root.append(&node);
+            } else {
+                continue;
             }
         }
 
-        std.debug.warn("{} tokens\n", i);
+        return root;
-
-        //return Expr{ .Number = ast.Number{ .Integer32 = 69 } };
-        //return self.root;
-        var expr = self.expression() catch |parse_err| {
-            return null;
-        };
-
-        return &expr;
     }
 };

src/runner.zig

@@ -44,22 +44,12 @@ pub const Runner = struct {
 
         scanner = scanners.Scanner.init(self.allocator, code);
         var parser = Parser.init(self.allocator, &scanner);
-        var expr_opt = try parser.parse();
+        var root = try parser.parse();
 
-        //var expr = ast.mkBinary(
+        var it = root.Root.iterator();
-        //    &ast.mkUnary(
-        //        tokens.Token{ .ttype = .Minus, .lexeme = "-", .line = 1 },
-        //        &ast.mkNum(i32, 123),
-        //    ),
-        //    tokens.Token{ .ttype = .Star, .lexeme = "*", .line = 1 },
-        //    &ast.mkGrouping(&ast.mkNum(f32, 45.67)),
-        //);
 
-        if (expr_opt) |expr_ptr| {
+        while (it.next()) |node| {
-            printer.printAst(expr_ptr);
+            std.debug.warn("{}\n", node.*);
-            std.debug.warn("\n");
-        } else {
-            return Result.CompileError;
         }
 
         return Result.Ok;