From 63d618e06f4d1d224aff4bf36cbb3f756c03c07d Mon Sep 17 00:00:00 2001
From: Fernando Araoz <fernando@araozu.dev>
Date: Fri, 31 Jan 2025 19:08:25 -0500
Subject: [PATCH] feat: implementar msg de error dinamicos

---
 src/01_lexic/token.zig     | 21 +++++++++++++++++++++
 src/02_syntax/variable.zig | 15 ++++++++++++++-
 src/context/root.zig       | 20 ++++++++++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/src/01_lexic/token.zig b/src/01_lexic/token.zig
index 73d0cca..35e217a 100644
--- a/src/01_lexic/token.zig
+++ b/src/01_lexic/token.zig
@@ -18,6 +18,27 @@ pub const TokenType = enum {
     Newline,
     // Each keyword will have its own token
     K_Var,
+
+    pub fn to_string(self: *TokenType) []const u8 {
+        return switch (self.*) {
+            TokenType.Int => "Int",
+            TokenType.Float => "Float",
+            TokenType.Identifier => "Identifier",
+            TokenType.Datatype => "Datatype",
+            TokenType.Operator => "Operator",
+            TokenType.Comment => "Comment",
+            TokenType.String => "String",
+            TokenType.LeftParen => "LeftParen",
+            TokenType.RightParen => "RightParen",
+            TokenType.LeftBracket => "LeftBracket",
+            TokenType.RightBracket => "RightBracket",
+            TokenType.LeftBrace => "LeftBrace",
+            TokenType.RightBrace => "RightBrace",
+            TokenType.Comma => "Comma",
+            TokenType.Newline => "Newline",
+            TokenType.K_Var => "K_Var",
+        };
+    }
 };
 
 pub const Token = struct {
diff --git a/src/02_syntax/variable.zig b/src/02_syntax/variable.zig
index 22d66a4..e8f6390 100644
--- a/src/02_syntax/variable.zig
+++ b/src/02_syntax/variable.zig
@@ -47,7 +47,20 @@ pub const VariableBinding = struct {
 
         // try to parse an identifier
         const identifier = if (utils.expect_token_type(lexic.TokenType.Identifier, &tokens.items[pos + 1])) |i| i else {
-            // TODO: populate error information
+            const faulty_token = &tokens.items[pos + 1];
+            var err = try ctx.create_and_append_error(
+                "Invalid variable declaration",
+                faulty_token.start_pos,
+                faulty_token.start_pos + faulty_token.value.len,
+            );
+            const token_name = faulty_token.token_type.to_string();
+            const error_name = try std.fmt.allocPrint(ctx.allocator, "Expected an identifier here, found a {s}", .{token_name});
+            try err.add_label(ctx.create_error_label_alloc(
+                error_name,
+                faulty_token.start_pos,
+                faulty_token.start_pos + faulty_token.value.len,
+            ));
+
             return ParseError.Error;
         };
 
diff --git a/src/context/root.zig b/src/context/root.zig
index 8afbe24..3757ad5 100644
--- a/src/context/root.zig
+++ b/src/context/root.zig
@@ -64,6 +64,26 @@ pub const CompilerContext = struct {
         };
     }
 
+    /// Creates a new ErrorLabel with a dynamic message.
+    /// Resource cleanup is automatic.
+    ///
+    /// `message` **must** be allocated with the allocator
+    /// of this context, because on cleanup this will be
+    /// passed to `ctx.allocator.destroy(message)`.
+    pub fn create_error_label_alloc(
+        self: *CompilerContext,
+        message: []u8,
+        start: usize,
+        end: usize,
+    ) ErrorLabel {
+        _ = self;
+        return .{
+            .message = .{ .dynamic = message },
+            .start = start,
+            .end = end,
+        };
+    }
+
     pub fn deinit(self: *CompilerContext) void {
         for (self.errors.items) |*error_item| {
             error_item.deinit(self.allocator);