From e2438f143b722d944e778cf4ead13673d45fc816 Mon Sep 17 00:00:00 2001
From: Luna <git@l4.pm>
Date: Mon, 1 Jul 2019 15:25:07 -0300
Subject: [PATCH] work towards FnDecl ast node

---
 src/ast.zig    |  2 +-
 src/parser.zig | 34 ++++++++++++++++++++++++++--------
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/src/ast.zig b/src/ast.zig
index 4de4f03..a2b1834 100644
--- a/src/ast.zig
+++ b/src/ast.zig
@@ -10,7 +10,7 @@ pub const NodeType = enum {
 };
 
 pub const FnDecl = struct {
-    func_name: []const u8,
+    func_name: Token,
 };
 
 pub const Node = union(NodeType) {
diff --git a/src/parser.zig b/src/parser.zig
index e43588e..6142051 100644
--- a/src/parser.zig
+++ b/src/parser.zig
@@ -90,26 +90,44 @@ pub const Parser = struct {
         return Result.CompileError;
     }
 
-    fn mkFnDecl(self: *Parser, name: []const u8) !*ast.Node {
-        var node = try self.allocator.create(Node.FnDecl);
-        node.* = Node.FnDecl{ .name = name };
+    fn consumeSingle(self: *Parser, ttype: TokenType) !Token {
+        if (self.check(ttype)) return self.advance();
+
+        var buf_main: [1000]u8 = undefined;
+        var buf = try std.fmt.bufPrint(
+            buf_main[0..],
+            "expected {}, got {}",
+            ttype,
+            self.peek().ttype,
+        );
+        try self.tokenError(self.peek(), buf);
+
+        return Result.CompileError;
+    }
+
+    fn mkFnDecl(self: *Parser, name: Token) !*ast.Node {
+        var node = try self.allocator.create(Node);
+        node.* = Node{ .FnDecl = ast.FnDecl{ .func_name = name } };
         return node;
     }
 
     fn functionDecl(self: *Parser) !*ast.Node {
         // get the name
         var name = try self.consume(.Identifier, "expected function name");
+        _ = try self.consumeSingle(.LeftParen);
         return try self.mkFnDecl(name);
     }
 
-    fn processToken(self: *Parser, token: Token) Result!ast.Node {
-        switch (token.ttype) {
-            //.Fn => try self.functionDecl(),
+    fn processToken(self: *Parser, token: Token) !*ast.Node {
+        var node = switch (token.ttype) {
+            .Fn => try self.functionDecl(),
             else => blk: {
                 try self.doError("TODO handle {}\n", token.ttype);
                 return Result.CompileError;
             },
-        }
+        };
+
+        return node;
     }
 
     pub fn parse(self: *Parser) !*ast.Node {
@@ -128,7 +146,7 @@ pub const Parser = struct {
                 if (token.ttype == .EOF) break;
 
                 var node = try self.processToken(token);
-                try root.Root.append(&node);
+                try root.Root.append(node);
             } else {
                 continue;
             }