Package antlr
Class ASTFactory
java.lang.Object
antlr.ASTFactory
AST Support code shared by TreeParser and Parser.
We use delegation to share code (and have only one
bit of code to maintain) rather than subclassing
or superclassing (forces AST support code to be
loaded even when you don't want to do AST stuff).
Typically, setASTNodeType is used to specify the
homogeneous type of node to create, but you can override
create to make heterogeneous nodes etc...
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionASTFactory
(Hashtable tokenTypeToClassMap) Create factory with a specific mapping from token type to Java AST node type. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addASTChild
(ASTPair currentAST, AST child) Add a child to the current ASTcreate()
Create a new empty AST node; if the user did not specify an AST node type, then create a default one: CommonAST.create
(int type) Create an AST node with the token type and text passed in, but with a specific Java object type.Create a new empty AST node; if the user did not specify an AST node type, then create a default one: CommonAST.ANTLR generates reference to this when you reference a token that has a specified heterogeneous AST node type.protected AST
protected AST
createUsingCtor
(Token token, String className) Copy a single node with same Java AST objec type.Duplicate tree including siblings of root.Duplicate a tree, assuming this is a root node of a tree-- duplicate that node and what's below; ignore siblings of root node.void
To change where error messages go, can subclass/override this method and then setASTFactory in Parser and TreeParser.getASTNodeType
(int tokenType) For a given token type, what is the AST node object type to create for it?Make a tree from a list of nodes.Make a tree from a list of nodes, where the nodes are contained in an ASTArray objectvoid
makeASTRoot
(ASTPair currentAST, AST root) Make an AST the root of current ASTvoid
void
void
Deprecated.since 2.7.1void
setTokenTypeASTNodeType
(int tokenType, String className) Specify an "override" for the Java AST object created for a specific token.void
setTokenTypeToASTClassMap
(Hashtable tokenTypeToClassMap)
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Field Details
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theASTNodeType
Name of AST class to create during tree construction. Null implies that the create method should create a default AST type such as CommonAST. This is for homogeneous nodes. -
theASTNodeTypeClass
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tokenTypeToASTClassMap
How to specify the classname to create for a particular token type. Note that ANTLR allows you to say, for example, tokens { PLUS<AST=PLUSNode>; ... } and it tracks everything statically. #[PLUS] will make you a PLUSNode w/o use of this table. For tokens that ANTLR cannot track statically like #[i], you can use this table to map PLUS (Integer) -> PLUSNode (Class) etc... ANTLR sets the class map from the tokens {...} section via the ASTFactory(Hashtable) ctor in antlr.Parser.
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Constructor Details
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ASTFactory
public ASTFactory() -
ASTFactory
Create factory with a specific mapping from token type to Java AST node type. Your subclasses of ASTFactory can override and reuse the map stuff.
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Method Details
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setTokenTypeASTNodeType
public void setTokenTypeASTNodeType(int tokenType, String className) throws IllegalArgumentException Specify an "override" for the Java AST object created for a specific token. It is provided as a convenience so you can specify node types dynamically. ANTLR sets the token type mapping automatically from the tokens{...} section, but you can change that mapping with this method. ANTLR does it's best to statically determine the node type for generating parsers, but it cannot deal with dynamic values like #[LT(1)]. In this case, it relies on the mapping. Beware differences in the tokens{...} section and what you set via this method. Make sure they are the same. Set className to null to remove the mapping.- Throws:
IllegalArgumentException
- Since:
- 2.7.2
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getASTNodeType
For a given token type, what is the AST node object type to create for it?- Since:
- 2.7.2
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addASTChild
Add a child to the current AST -
create
Create a new empty AST node; if the user did not specify an AST node type, then create a default one: CommonAST. -
create
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create
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create
Create an AST node with the token type and text passed in, but with a specific Java object type. Typically called when you say @[PLUS,"+",PLUSNode] in an antlr action.- Since:
- 2.7.2
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create
Create a new empty AST node; if the user did not specify an AST node type, then create a default one: CommonAST. -
create
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create
ANTLR generates reference to this when you reference a token that has a specified heterogeneous AST node type. This is also a special case node creation routine for backward compatibility. Before, ANTLR generated "new T(tokenObject)" and so I must call the appropriate constructor not T().- Since:
- 2.7.2
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create
- Since:
- 2.7.2
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createUsingCtor
- Since:
- 2.7.2
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create
- Since:
- 2.7.2
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dup
Copy a single node with same Java AST objec type. Ignore the tokenType->Class mapping since you know the type of the node, t.getClass(), and doing a dup. clone() is not used because we want all AST creation to go thru the factory so creation can be tracked. Returns null if t is null. -
dupList
Duplicate tree including siblings of root. -
dupTree
Duplicate a tree, assuming this is a root node of a tree-- duplicate that node and what's below; ignore siblings of root node. -
make
Make a tree from a list of nodes. The first element in the array is the root. If the root is null, then the tree is a simple list not a tree. Handles null children nodes correctly. For example, build(a, b, null, c) yields tree (a b c). build(null,a,b) yields tree (nil a b). -
make
Make a tree from a list of nodes, where the nodes are contained in an ASTArray object -
makeASTRoot
Make an AST the root of current AST -
setASTNodeClass
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setASTNodeClass
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setASTNodeType
Deprecated.since 2.7.1Specify the type of node to create during tree building. -
getTokenTypeToASTClassMap
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setTokenTypeToASTClassMap
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error
To change where error messages go, can subclass/override this method and then setASTFactory in Parser and TreeParser. This method removes a prior dependency on class antlr.Tool.
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