add basics of generic command parsing

src/lang.zig

@@ -318,32 +318,51 @@ pub const Lang = struct {
                 self.doError("No command given", .{});
                 continue;
             }
-            var command = cmd_opt.?;
+            const command_string = cmd_opt.?;
 
-            var ctype_opt = self.getCommand(command);
-            var ctype: CommandType = undefined;
-            if (ctype_opt) |ctype_val| {
-                ctype = ctype_val;
-            } else {
-                self.doError("Unknown command '{}' ({})", .{ command, command.len });
+            var found: bool = false;
+
+            inline for (@typeInfo(NewCommand).Struct.decls) |cmd_struct_decl| {
+                const struct_name = cmd_struct_decl.name;
+                comptime var lowered_command_name = [_]u8{0} ** struct_name.len;
+                comptime {
+                    for (struct_name) |c, i| {
+                        lowered_command_name[i] = std.ascii.toLower(c);
+                    }
+                }
+
+                if (std.mem.eql(u8, &lowered_command_name, command_string)) {
+                    found = true;
+
+                    // Based on the command struct fields, we need to decide
+                    // how to actually get its arguments and creating the struct
+                    // itself.
+
+                    const command_struct = cmd_struct_decl.data.Type;
+                    var cmd: command_struct = undefined;
+                    inline for (@typeInfo(command_struct).Struct.fields) |cmd_field| {
+
+                        // TODO: crash when no arguments are left but we still need
+                        // arguments...
+                        const argument = tok_it.next().?;
+                        const argument_value = switch (cmd_field.field_type) {
+                            usize => try std.fmt.parseInt(usize, arg, 10),
+                            i32 => try std.fmt.parseInt(i32, arg, 10),
+                            f32 => try std.fmt.parseFloat(f32, arg),
+                            else => @panic("Invalid parameter type (" ++ @typeName(cmd_field.field_type) ++ ") left on command struct " ++ @typeName(command_struct) ++ "."),
+                        };
+
+                        @field(cmd, cmd_field.name) = argument_value;
+                    }
+                }
+            }
+
+            if (!found) {
+                self.doError("Unknown command '{}' ({})", .{ command_string, command_string.len });
                 continue;
             }
 
-            var args = ArgList.init(self.allocator);
-            errdefer args.deinit();
-
-            while (tok_it.next()) |arg| {
-                try args.append(arg);
-            }
-
-            // construct final Command based on command
-            var cmd = Command{ .command = ctype, .args = args };
-            self.validateCommand(cmd) catch |err| {
-                //self.doError("error validating command '{}': {}", command, err);
-                continue;
-            };
-
-            try cmds.append(cmd);
+            // try cmds.append(cmd);
         }
 
         if (self.has_error) return ParseError.ParseFail;