DLog v2 - Complete re-write

README.md

@@ -35,9 +35,15 @@ dlog is formed out of two main components:
 
 1. `Logger`
 	* The logger contains the needed barebones for facilitating the actual logging of text
-2. `MessageTransform`
-	* A MessageTransform is attached to a logger and performs manipulation on the text input into the logger for logging
+	* The _base logger_ (i.e. `Logger`) maintains a list of attaches _filters_, _message transformers_ and _handlers_
+2. `Filter`
+	* Acts as a predicate on the incoming _message_ and determines whether it should be logged or not
+	* This is used by the `BasicLogger` to implement log levels
+3. `Transform`
+	* A _message transform_ is attached to a logger and performs manipulation on the message logged
 	* They may be chained as to perform multiple transformations in a stream-like fashion
+4. `Handler`
+	* A _handler_ handles the final transformed message, for some this means outputting to standard out, or a file
 
 ### Quick start
 
@@ -47,60 +53,29 @@ simply use the default logger as follows:
 ```d
 import dlog;
 
-Logger logger = new DefaultLogger();
+DefaultLogger logger = new DefaultLogger();
 
-
-logger.log("This is a log message");
-logger.log(1);
-logger.log(1==1);
-logger.log([1,2,3]);
-```
-
-This will output the following:
-
-```
-[2021-Dec-23 11:17:35.3527637]	(source/dlog/testing/thing.d:12): This is a log message
-[2021-Dec-23 11:17:35.3527717]	(source/dlog/testing/thing.d:13): 1
-[2021-Dec-23 11:17:35.3527789]	(source/dlog/testing/thing.d:14): true
-[2021-Dec-23 11:17:35.3527871]	(source/dlog/testing/thing.d:15): [1, 2, 3]
-```
-
-As you can see file and line numbering of where the `log()` function is called appears in the log message which can be quite helpful
-for debugging.
-
----
-
-We also support many different logging levels which can be accomplished using the `error`, `debug_` (or the `dbg` alias), `info `(the default) and `warn`:
-
-```d
-Logger logger = new DefaultLogger();
-
-// Create a default logger with the default joiner
-logger = new DefaultLogger();
-
-// Test out `error()`
+logger.setLevel(Level.DEBUG);
 logger.error(["woah", "LEVELS!"], 69.420);
-
-// Test out `info()`
 logger.info(["woah", "LEVELS!"], 69.420);
-
-// Test out `warn()`
 logger.warn(["woah", "LEVELS!"], 69.420);
-
-// Test out `debug_()`
 logger.debug_(["woah", "LEVELS!"], 69.420);
+
+// Should not be able to see this
+logger.setLevel(Level.INFO);
+logger.debug_("Can't see me!");
 ```
 
-This outputs the following:
+This will output the following:
 
 ```
-[2023-Mar-03 11:33:49.2617904]	(source/dlog/core.d:427): ["woah", "LEVELS!"] 69.42
-[2023-Mar-03 11:33:49.2618091]	(source/dlog/core.d:430): ["woah", "LEVELS!"] 69.42
-[2023-Mar-03 11:33:49.2618273]	(source/dlog/core.d:433): ["woah", "LEVELS!"] 69.42
-[2023-Mar-03 11:33:49.2618457]	(source/dlog/core.d:436): ["woah", "LEVELS!"] 69.42
+[2024-Apr-09 19:14:38.3077171]  (ERROR): ["woah", "LEVELS!"] 69.42
+[2024-Apr-09 19:14:38.3077346]  (INFO): ["woah", "LEVELS!"] 69.42
+[2024-Apr-09 19:14:38.3077559]  (WARN): ["woah", "LEVELS!"] 69.42
+[2024-Apr-09 19:14:38.3077759]  (DEBUG): ["woah", "LEVELS!"] 69.42
 ```
 
-You can also look into `logc(Context, string)` which allows you to use a `Context` object when logging, more information available in the [full API](https://dlog.dpldocs.info/v0.3.19/dlog.context.html).
+You can see the [full API](https://dlog.dpldocs.info/v0.3.19/dlog.context.html) for more information.
 
 ### Custom loggers
 
@@ -110,64 +85,32 @@ Perhaps the default transformation, `DefaultTransform`, may not be what you want
 messages or perhaps don't want the date-and-timestamp included at all. All of this can be up to you if you choose to implement your own
 message transform.
 
-You will need to start off with a class that inherits from the `MessageTransform` class and then which overrides the `transform` method as shown below:
+You will need to start off with a class that inherits from the `Transform` class and then which overrides the `transform` method as shown below:
 
 ```d
 import dlog;
 
-public class CustomTranform : MessageTransform
+public class CustomTranform : Transform
 {
-	public override string transform(string text, Context context)
+	public override Message transform(Message message)
 	{
-		string transformed;
+		BasicMessage bmesg = cast(BasicMessage)message;
+
+		// Only handle BasicMessage(s) - ones which have `setText(string)`
+		if(bmesg is null)
+		{
+			return message;
+		}
 
-		/* Insert code to transform `text` and return the `transformed` text */
+		string transformed;
+		/* Insert transformation code here */
+		bmesg.setText(transformed);
 
-		return transformed;
+		return message;
 	}
 }
 ```
 
-Additional information, besides the text being logged itself (this is the `string text` argument), comes in the form of a `Context` object `context`. What one can get from this is a `CompilationInfo` struct which contains the following fields below if one calls `toArray()` on
-it which will return a string array shown below (we refer to this array as `lineInfo`):
-
-1. `lineInfo[0]`
-    * This contains `__FILE_FULL_PATH__` which is the full path (absolute) to the source file where `log()` was called
-2. `lineInfo[1]`
-    * This contains `__FILE__` which is the path (starting at `source/` to the source file where `log()` was called
-3. `lineInfo[2]`
-    * This contains a stringified version of `__LINE__` which is the line number of the call to `log()`
-4. `lineInfo[3]`
-    * This contains `__MODULE__` which is the name of the module the call to `log()` appeared in
-5. `lineInfo[4]`
-    * This contains `__FUNCTION__` which is the name of the function `log()` was called in
-6. `lineInfo[5]`
-    * This contains `__PRETTY_FUNCTION__` which is the same as above but with type information
-
-The point of a `Context` object is also such that a custom transformer may expect a kind-of `Context` like a custom one (i.e. `CustomContext`)
-which perhaps a custom logger (kind-of `Logger`) can then have set certain fields in it.
-
-## Creating a Logger
-
-We now need to create a logger that makes use of our message transform, we can do so by creating an instance
-of the `Logger` class and passing in our `MessageTransform` as so:
-
-```d
-Logger customLogger = new DefaultLogger(new CustomTranform());
-```
-
-The above is all one needs to be able to pull off a custom transformation.
-
-### Custom Logger
-
-Custom loggers can also be created by sub-classing the `Logger` class and overriding the `logImpl(string)` method.
-The reason someone may want to do this is up to them. One easy to think of reason is to perhaps applying filtering
-of messages to be logged and skip them (as this method is where the I/O of printing out the logs normally happens).
-Another reason may be to log to a different data resource, the `DefaultLogger` writes to the file descriptor `0` (stdout),
-but you may want to log over a socket connection to a remote machine for example, or perhaps do several pieces of
-I/O for your logging. One can do that with a custom logger, you shoudl see `source/dlog/defaults.d` for the implementation
-of a custom logger, such as `DefaultLogger`.
-
 ## License
 
 LGPL v3