Parser

java.lang.Object
- com.google.javascript.jscomp.parsing.parser.Parser

```
public class Parser
extends java.lang.Object
```
Parses a javascript file.
The various parseX() methods never return null - even when parse errors are encountered. Typically parseX() will return a XTree ParseTree. Each ParseTree that is created includes its source location. The typical pattern for a parseX() method is:
```
 XTree parseX() {
   SourcePosition start = getTreeStartLocation();
   parse X grammar element and its children
   return new XTree(getTreeLocation(start), children);
 }
 
```
parseX() methods must consume at least 1 token - even in error cases. This prevents infinite loops in the parser.
Many parseX() methods are matched by a 'boolean peekX()' method which will return true if the beginning of an X appears at the current location. There are also peek() methods which examine the next token. peek() methods must not consume any tokens.
The eat() method consumes a token and reports an error if the consumed token is not of the expected type. The eatOpt() methods consume the next token iff the next token is of the expected type and return the consumed token or null if no token was consumed.
When parse errors are encountered, an error should be reported and the parse should return a best guess at the current parse tree.
When parsing lists, the preferred pattern is:
```
   eat(LIST_START);
   ImmutableList.Builder<ParseTree> elements = ImmutableList.builder();
   while (peekListElement()) {
     elements.add(parseListElement());
   }
   eat(LIST_END);
 
```

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Parser.Config

Constructor Summary

Constructors
Constructor Description

Parser(Parser.Config config, ErrorReporter errorReporter, SourceFile source)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.util.List<Comment>`	`getComments()`
`FeatureSet`	`getFeatures()`
`java.lang.String`	`getSourceMapURL()`	Returns the url provided by the sourceMappingURL if any was found.
`ProgramTree`	`parseProgram()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Parser

public Parser(Parser.Config config,
              ErrorReporter errorReporter,
              SourceFile source)

Method Detail

getComments

public java.util.List<Comment> getComments()

getFeatures
```
public FeatureSet getFeatures()
```

getSourceMapURL
```
@Nullable
public java.lang.String getSourceMapURL()
```
Returns the url provided by the sourceMappingURL if any was found.

parseProgram
```
public ProgramTree parseProgram()
```