revert target documentation

doc/dart-target.md

@@ -1,103 +0,0 @@
-# ANTLR4 Runtime for Dart
-
-### First steps
-
-#### 1. Install ANTLR4
-
-[The getting started guide](https://github.com/antlr/antlr4/blob/master/doc/getting-started.md) 
-should get you started.
-
-#### 2. Install the Dart ANTLR runtime
-
-Each target language for ANTLR has a runtime package for running parser 
-generated by ANTLR4. The runtime provides a common set of tools for using your parser.
-
-Install the runtime with Composer:
-
-```bash
-composer install antlr/antlr4
-```
-
-#### 3. Generate your parser
-
-You use the ANTLR4 "tool" to generate a parser. These will reference the ANTLR 
-runtime, installed above.
-
-Suppose you're using a UNIX system and have set up an alias for the ANTLR4 tool 
-as described in [the getting started guide](https://github.com/antlr/antlr4/blob/master/doc/getting-started.md). 
-To generate your Dart parser, run the following command:
-
-```bash
-antlr4 -Dlanguage=Dart MyGrammar.g4
-```
-
-For a full list of antlr4 tool options, please visit the 
-[tool documentation page](https://github.com/antlr/antlr4/blob/master/doc/tool-options.md).
-
-### Complete example
-
-Suppose you're using the JSON grammar from https://github.com/antlr/grammars-v4/tree/master/json.
-
-Then, invoke `antlr4 -Dlanguage=Dart JSON.g4`. The result of this is a 
-collection of `.Dart` files in the `parser` directory including:
-```
-JsonParser.Dart
-JsonBaseListener.Dart
-JsonLexer.Dart
-JsonListener.Dart
-```
-
-Another common option to the ANTLR tool is `-visitor`, which generates a parse 
-tree visitor, but we won't be doing that here. For a full list of antlr4 tool 
-options, please visit the [tool documentation page](tool-options.md).
-
-We'll write a small main func to call the generated parser/lexer 
-(assuming they are separate). This one writes out the encountered 
-`ParseTreeContext`'s:
-
-```Dart
-import 'packages:antlr4/antlr4.dart';
-import 'P';
-
-class TreeShapeListener implements ParseTreeListener {
-    void visitTerminal(TerminalNode node) {}
-    void visitErrorNode(ErrorNode node) {}
-    void exitEveryRule(ParserRuleContext ctx) {}
-
-    void enterEveryRule(ParserRuleContext ctx) {
-        print(ctx.text);
-    }
-}
-main () {
-}
-
-$input = InputStream::fromPath($argv[1]);
-$lexer = new JSONLexer($input);
-$tokens = new CommonTokenStream($lexer);
-$parser = new JSONParser($tokens);
-$parser->addErrorListener(new DiagnosticErrorListener());
-$parser->setBuildParseTree(true);
-$tree = $parser->json();
-
-ParseTreeWalker::default()->walk(new TreeShapeListener(), $tree);
-```
-
-Create a `example.json` file:
-```json
-{"a":1}
-```
-
-Parse the input file:
-
-```
-dart json.Dart example.json
-```
-
-The expected output is:
-
-```
-{"a":1}
-{"a":1}
-"a":1
-1
-```