StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
3912319
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
8
CommunityOwnedDate
CreationDate
2010-10-12T07:05:39.867
FavoriteCount
0
LastActivityDate
2010-10-12T12:36:59.667
LastEditDate
2010-10-12T12:36:59.667
LastEditorUserId
50476
OwnerUserId
50476
ParentId
3909957
PostTypeId
2
Score
11
ViewCount
0
LastEditorDisplayName
text
Body
<blockquote> Jason S wrote: Is there a way to do this? </blockquote> Yes. First define your grammar (I took your example of an expression parser with only the <code>+</code> and <code>*</code> and <code>()</code> operators): <pre><code>grammar Exp; // parser rules parse : additionExp ; additionExp : multiplyExp (Add multiplyExp)* ; multiplyExp : atomExp (Mult atomExp)* ; atomExp : Number | LParen additionExp RParen ; // lexer rules Add : '+' ; Mult : '*' ; LParen : '(' ; RParen : ')' ; Number : ('0'..'9')+ ('.' ('0'..'9')+)? ; Spaces : (' ' | '\t' | '\r'| '\n') {$channel=HIDDEN;} ; </code></pre> If you want to let ANTLR generate a proper AST from the grammar above, you must put the following at the top of your grammar (under the grammar declaration): <pre><code>options { output=AST; } </code></pre> and you must indicate what the root of each of your parse rules should be. This can be done in two ways: <ol> <li>by using <a href="http://www.antlr.org/wiki/display/~admin/2008/04/11/Rewrite+rules">rewrite rules</a>;</li> <li>or by placing one of the "inline tree-operators" <code>^</code> and <code>!</code> after the tokens: <ul> <li><code>^</code> means: make this token the root;</li> <li><code>!</code> means: exclude this token from the AST.</li> </ul></li> </ol> Now your grammar would look like this: <pre><code>grammar Exp; options { output=AST; } // parser rules parse : additionExp ; additionExp : multiplyExp (Add^ multiplyExp)* ; multiplyExp : atomExp (Mult^ atomExp)* ; atomExp : Number | LParen! additionExp RParen! ; // lexer rules Add : '+' ; Mult : '*' ; LParen : '(' ; RParen : ')' ; Number : ('0'..'9')+ ('.' ('0'..'9')+)? ; Spaces : (' ' | '\t' | '\r'| '\n') {$channel=HIDDEN;} ; </code></pre> As you can see, I made the <code>Add</code> and <code>Mult</code> roots, and excluded the parenthesis. Now generate a lexer & parser from the grammar: <pre><code>java -cp antlr-3.2.jar org.antlr.Tool Exp.g </code></pre> create a little test harness: <pre><code>import org.antlr.runtime.*; import org.antlr.runtime.tree.*; import java.util.*; public class Main { private static void preOrder(CommonTree tree, int depth) { for(int i = 0; i < depth; i++) { System.out.print("- "); } System.out.println("> "+tree + " :: " + ExpParser.tokenNames[tree.getType()]); List children = tree.getChildren(); if(children == null) return; for(Object o : children) { preOrder((CommonTree)o, depth+1); } } public static void main(String[] args) throws Exception { ANTLRStringStream in = new ANTLRStringStream("3 * (4 + 7 * 6) * (3 + 7 * (4 + 2))"); ExpLexer lexer = new ExpLexer(in); CommonTokenStream tokens = new CommonTokenStream(lexer); ExpParser parser = new ExpParser(tokens); CommonTree tree = (CommonTree)parser.parse().getTree(); preOrder(tree, 0); } } </code></pre> compile everything: <pre><code>javac -cp antlr-3.2.jar *.java </code></pre> and run the <code>Main</code> class: <pre><code>// *nix/Mac OS java -cp .:antlr-3.2.jar Main // Windows java -cp .;antlr-3.2.jar Main </code></pre> which produces the following: <pre><code>> * :: Mult - > * :: Mult - - > 3 :: Number - - > + :: Add - - - > 4 :: Number - - - > * :: Mult - - - - > 7 :: Number - - - - > 6 :: Number - > + :: Add - - > 3 :: Number - - > * :: Mult - - - > 7 :: Number - - - > + :: Add - - - - > 4 :: Number - - - - > 2 :: Number </code></pre> As you can see, the <code>parse</code> rule (method) returns a <a href="http://www.antlr.org/api/Java/classorg_1_1antlr_1_1runtime_1_1tree_1_1_common_tree.html"><code>CommonTree</code></a> object you can use to create your own walker/visitor leaving the grammar as is. HTH
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POANTLR (or alternative): decoupling parsing from evaluation
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USBart Kiers
UserOwnerUserId
1. USBart Kiers
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POANTLR (or alternative): decoupling parsing from evaluation
 singulars
 PostTypePostTypeId
 PTQuestion
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTAcceptedByOriginator
3. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.