Update readme (#245)

Author: andrey-zherikov

README.md

@@ -6,213 +6,10 @@
 `argparse` is a flexible utility for [D programming language](https://dlang.org/) to parse command line arguments.
 
 > [!WARNING]
-> :warning: Please be aware that current HEAD contains breaking changes comparing to 1.* 
+> :warning: Version 2.* contains breaking changes comparing to 1.* - see [change log](https://github.com/andrey-zherikov/argparse/releases) for details
 > 
 > :warning: This includes changes in documentation - documentation for 1.* version is [here](https://github.com/andrey-zherikov/argparse/blob/release/1.x/README.md)
 
-## Changes since 1.* version
-
-<details>
-<summary>Changelog</summary>
-
-### Breaking changes
-
-* Changes in `Config`:
-
-  * Custom error handler function (`Config.errorHandler`) now receives message text with ANSI styling if styling is enabled. One can use `argparse.ansi.getUnstyledText` function to remove any styling - this function returns a range of unstyled `string` objects which can be used as is or `join`'ed into a string if  needed: `message.getUnstyledText.join`.
-
-  * `Config.addHelp` is renamed to `Config.addHelpArgument`.
-
-  * `Config.arraySep` is renamed to `Config.valueSep`.
-
-  * `Config.caseSensitive` is replaced with `Config.caseSensitiveShortName`, `Config.caseSensitiveLongName` and `Config.caseSensitiveSubCommand`.
-    There is also a "new" `Config.caseSensitive` function/property helper that sets all above settings to a specific value.
-
-  * `Config.endOfArgs` is renamed to `Config.endOfNamedArgs`.
-
-  * `Config.helpStyle` is renamed to `Config.styling`.
-
-  * `Config.namedArgChar` is replaced with `Config.shortNamePrefix` and `Config.longNamePrefix`.
-
-  * `Config.stylingMode` remains unchanged even if it was set to `autodetect`. One should check `ansiStylingArgument.stdoutStyling`
-    or `ansiStylingArgument.stderrStyling` to determine whether styling should be enabled.
-
-* `Style.namedArgumentName` is renamed to `Style.argumentName`.
-
-* Underlying type of `ansiStylingArgument` argument is changed. It supports detection and tracking of styling for stdout and stderr
-  separately: use `ansiStylingArgument.stdoutStyling` and `ansiStylingArgument.stderrStyling` for this.
-  Also it can be cast to boolean which is an equivalent to `ansiStylingArgument.stdoutStyling`.
-
-  So if you use it:
-  ```d
-    static auto color = ansiStylingArgument;
-  ```
-  then you should replace
-  ```d
-    if(args.color == Config.StylingMode.on)
-  ```
-  with
-  ```d
-    if(args.color)
-    // or
-    if(args.color.stdoutStyling)
-    // or
-    if(ansiStylingArgument.stdoutStyling)
-  ```
-
-* `@SubCommands` UDA is removed. One should use `SubCommand` template instead of `SumType`.
-  All calls to `std.sumtype.match` should be replaced with `matchCmd`.
-
-  Simply replace
-  ```d
-    @SubCommands SumType!(CMD1, CMD2, Default!CMD3) cmd;
-    ...
-    cmd.match!...;
-  ```
-  with
-  ```d
-    SubCommand!(CMD1, CMD2, Default!CMD3) cmd;
-    ...
-    cmd.matchCmd!...;
-  ```
-
-* `@TrailingArguments` UDA is removed: all command line parameters that appear after double-dash `--` are considered as positional arguments.
-  So if those parameters are to be parsed, use `@PositionalArgument` instead of `@TrailingArguments`.
-
-* Functions for parsing customization (`PreValidation`, `Parse`, `Validation` and `Action`) now accept functions as runtime parameters instead of template arguments
-
-  For example, replace this
-  ```d
-    .Parse     !((string s) { return cast(char) s[1]; })
-    .Validation!((char v) { return v >= '0' && v <= '9'; })
-  ```
-  with
-  ```d
-    .Parse     ((string s) { return cast(char) s[1]; })
-    .Validation((char v) { return v >= '0' && v <= '9'; })
-  ```
-
-* `HideFromHelp` is renamed to `Hidden` and now also hides an argument from shell completion.
-
-* `AllowedValues` now accepts values as run-time parameters, not as template parameters.
-
-  For example, replace this
-  ```d
-    .AllowedValues!(["value1", "value2", value3"])
-  ```
-  with
-  ```d
-    .AllowedValues("value1", "value2", value3")
-  ```
-
-* `AllowNoValue` now accepts a value as run-time parameter, not as template parameter.
-
-  For example, replace this
-  ```d
-    .AllowNoValue!"myvalue"
-  ```
-  with
-  ```d
-    .AllowNoValue("myvalue")
-  ```
-
-* `RequireNoValue` is renamed to `ForceNoValue` and now accepts a value as run-time parameter, not as template parameter.
-
-  For example, replace this
-  ```d
-    .RequireNoValue!"myvalue"
-  ```
-  with
-  ```d
-    .ForceNoValue("myvalue")
-  ```
-
-* `ArgumentValue` is renamed to `AllowedValues`.
-
-  For example, replace this
-  ```d
-    .ArgumentValue("value1", "value2")
-  ```
-  with
-  ```d
-    .AllowedValues("value1", "value2")
-  ```
-
-* `parseArgs` template functions that received `newMain` template argument was removed. One should use either `main` template mixin
-  or non-templated `Result parseArgs(ref COMMAND receiver, string[] args)` function.
-
-* Removed `Result.Error(T...)(string msg, T extraArgs)` function. Users should explicitly specify result code using
-  `Result.Error(T...)(int resultCode, string msg, T extraArgs)`.
-
-* Dropped support for DMD-2.099.
-
-### Enhancements and bug fixes
-
-* Parsing procedure follows [POSIX.1-2024](https://pubs.opengroup.org/onlinepubs/9799919799/) meaning that `argparse` now
-  allows at most one value per appearance of named argument in command line. This means that `prog --param value1 value2`
-  is not working anymore by default - `--param` must be repeated: `prog --param value1 --param value2`.
-  However, `prog --param value1,value2` still works.
-  
-  To make `argparse` 2.* behave like 1.*, one should set `Config.variadicNamedArgument` to true.
-  See [documentation](https://andrey-zherikov.github.io/argparse/config.html#variadicNamedArgument) for details.
-
-* Fix for `Command()` UDA: `ArrayIndexError` is not thrown anymore.
-
-* Error messages are printed with `Config.styling` and now have the same styling as help text.
-
-* New `errorMessagePrefix` member in `Config.styling` that determines the style of "Error:" prefix in error messages. This prefix is printed in red by default.
-
-* New checks:
-  * Argument is not allowed to be in multiple argument groups.
-  * Subcommand name can't start with `Config.shortNamePrefix` (dash `-` by default) or `Config.longNamePrefix` (double-dash `--` by default).
-
-* Functions for parsing customization (`PreValidation`, `Parse`, `Validation` and `Action`) can now return `Result` through `Result.Success` or `Result.Error` and provide error message if needed.
-
-* Fixes for bundling of single-letter arguments.
-  For example, the following cases are supported for `bool b; string s;` arguments:
-  * `./prog -b -s=abc`
-  * `./prog -b -s abc`
-  * `./prog -b -sabc`
-  * `./prog -bsabc`
-  * `./prog -bs=abc`
-
-* Fixes for parsing of multiple values. Only these formats are supported:
-  * `./prog --arg value1 value2 value3`
-  * `./prog --arg=value1,value2,value3`
-
-* Values of multi-value positional argument can now be interleaved with named arguments.
-  For example, the following is the same when `arg1` and `arg2` are values for single `string[] args` positional argument:
-  * `--flag arg1 arg2`
-  * `arg1 --flag arg2`
-  * `arg1 arg2 --flag`
-
-* Long and short names of arguments are now separated:
-  * Short names are single-character names by default. This can be overridden by explicitly specifying short and long names in `NamedArgument` UDA.
-  * Short names can be specified with short prefix only (e.g. `-`).
-  * Long names can be specified with long prefix only (e.g. `--`).
-
-* Removed support for delegate in `Config.errorHandler`, `Description`, `ShortDescription`, `Usage` and `Epilog` because of compiler's `closures are not yet supported in CTFE`.
-
-* Added new `Config.assignKeyValueChar` parameter to customize assign character in `key=value` syntax for arguments with associative array type.
-
-* Added new `Config.errorExitCode` parameter to customize exit code in case of parsing error.
-
-* Added support of `@PositionalArgument` without explicit position. In this case positions are determined in the order of declarations of members.
-
-* Added support for environment fallback, so adding `EnvFallback("VAR")` to an argument would automatically populate the argument with the content
-  of the `VAR` environment variable if nothing is provided on the command line.
-
-* Fix for empty argument values: they are now non-null empty strings (`""` instead of `string.init` before).
-
-* Added support for classes.
-
-### Other changes
-
-* Removed dependency on `std.regex`.
-* New code base: library implementation is almost fully rewritten (public API was not changed in this effort). Unnecessary templates were replaced with regular functions. As a result, compilation time and memory usage were improved: 2x better for `dub build` and 4x better for `dub test`.
-* [New documentation](https://andrey-zherikov.github.io/argparse/)
-</details>
-
 
 ## Features