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POHow do I make a TreeParser in ANTLR3?
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  1. POHow do I make a TreeParser in ANTLR3?
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    copied!<p>I'm attemping to learn language parsing for fun...</p> <p>I've created a ANTLR grammar which I believe will match a simple language I am hoping to implement. It will have the following syntax:</p> <pre><code>&lt;FunctionName&gt; ( &lt;OptionalArguments&gt;+) { &lt;OptionalChildFunctions&gt;+ } </code></pre> <p>Actual Example:</p> <pre><code>ForEach(in:[1,2,3,4,5] as:"nextNumber") { Print(message:{nextNumber}) } </code></pre> <p>I believe I have the grammar working correctly to match this construct, and now I am attemping to build an Abstract Syntax Tree for the language.</p> <p>Firstly, I must admit I'm not exactly sure HOW this tree should look. Secondly, I'm at a complete loss how to do this in my Antlr grammar...I've been trying without much success for hours.</p> <p>This is the current idea I'm going with for the tree:</p> <pre><code> FunctionName / \ Attributes \ / \ / \ ID /\ ChildFunctions / \ ID etc / \ Attribute AttributeValue Type </code></pre> <p>This is my current Antlr grammar file:</p> <pre><code>grammar Test; options {output=AST;ASTLabelType=CommonTree;} program : function ; function : ID (OPEN_BRACKET (attribute (COMMA? attribute)*)? CLOSE_BRACKET)? (OPEN_BRACE function* CLOSE_BRACE)?; attribute : ID COLON datatype; datatype : NUMBER | STRING | BOOLEAN | array | lookup ; array : OPEN_BOX (datatype (COMMA datatype)* )? CLOSE_BOX ; lookup : OPEN_BRACE (ID (PERIOD ID)*) CLOSE_BRACE; NUMBER : ('+' | '-')? (INTEGER | FLOAT) ; STRING : '"' ( ESC_SEQ | ~('\\'|'"') )* '"' ; BOOLEAN : 'true' | 'TRUE' | 'false' | 'FALSE' ; ID : (LETTER|'_') (LETTER | INTEGER |'_')* ; COMMENT : '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;} | '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;} ; WHITESPACE : (' ' | '\t' | '\r' | '\n') {$channel=HIDDEN;} ; COLON : ':' ; COMMA : ',' ; PERIOD : '.' ; OPEN_BRACKET : '(' ; CLOSE_BRACKET : ')' ; OPEN_BRACE : '{' ; CLOSE_BRACE : '}' ; OPEN_BOX : '[' ; CLOSE_BOX : ']' ; fragment LETTER : 'a'..'z' | 'A'..'Z' ; fragment INTEGER : '0'..'9'+ ; fragment FLOAT : INTEGER+ '.' INTEGER* ; fragment ESC_SEQ : '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\') ; </code></pre> <p>ANY help / advice would be great. I've tried reading dozens of tutorials and nothing about the AST generation seems to stick :(</p>
 

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