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    <p>I wouldn't walk this manually if I were you. After generating a lexer and parser, ANTLR would also have generated a file called <code>CfscriptBaseListener</code> that has empty methods for all of your parser rules. You can let ANTLR walk your tree and attach a custom tree-listener in which you override only those methods/rules you're interested in.</p> <p>In your case, you probably want to be notified whenever a new function is created (to create a new scope) and you'll probably be interested in variable assignments (<code>variableStatement</code> and <code>nonVarVariableStatement</code>). Your listener, let's call is <code>VarListener</code> will keep track of all scopes as ANTLR walks the tree.</p> <p>I did change 1 rule slightly (I added <code>objectLiteralEntry</code>):</p> <pre>objectLiteral : '{' (objectLiteralEntry (',' objectLiteralEntry)*)? '}' ; objectLiteralEntry : Identifier '=' expression ; </pre> <p>which makes life easier in the following demo:</p> <h2>VarListener.java</h2> <pre class="lang-java prettyprint-override"><code>public class VarListener extends CfscriptBaseListener { private Stack&lt;Scope&gt; scopes; public VarListener() { scopes = new Stack&lt;Scope&gt;(); scopes.push(new Scope(null)); } @Override public void enterVariableStatement(CfscriptParser.VariableStatementContext ctx) { String varName = ctx.variableName().getText(); Scope scope = scopes.peek(); scope.add(varName); } @Override public void enterNonVarVariableStatement(CfscriptParser.NonVarVariableStatementContext ctx) { String varName = ctx.variableName().getText(); checkVarName(varName); } @Override public void enterObjectLiteralEntry(CfscriptParser.ObjectLiteralEntryContext ctx) { String varName = ctx.Identifier().getText(); checkVarName(varName); } @Override public void enterFunctionDeclaration(CfscriptParser.FunctionDeclarationContext ctx) { scopes.push(new Scope(scopes.peek())); } @Override public void exitFunctionDeclaration(CfscriptParser.FunctionDeclarationContext ctx) { scopes.pop(); } private void checkVarName(String varName) { Scope scope = scopes.peek(); if(scope.inScope(varName)) { System.out.println("OK : " + varName); } else { System.out.println("Oops : " + varName); } } } </code></pre> <p>A <code>Scope</code> object could be as simple as:</p> <h2>Scope.java</h2> <pre class="lang-java prettyprint-override"><code>class Scope extends HashSet&lt;String&gt; { final Scope parent; public Scope(Scope parent) { this.parent = parent; } boolean inScope(String varName) { if(super.contains(varName)) { return true; } return parent == null ? false : parent.inScope(varName); } } </code></pre> <p>Now, to test this all, here's a small main class:</p> <h2>Main.java</h2> <pre class="lang-java prettyprint-override"><code>import org.antlr.v4.runtime.*; import org.antlr.v4.runtime.tree.*; public class Main { public static void main(String[] args) throws Exception { CfscriptLexer lexer = new CfscriptLexer(new ANTLRFileStream("Test.cfc")); CfscriptParser parser = new CfscriptParser(new CommonTokenStream(lexer)); ParseTree tree = parser.component(); ParseTreeWalker.DEFAULT.walk(new VarListener(), tree); } } </code></pre> <p>If you run this <code>Main</code> class, the following will be printed:</p> <pre>Oops : testing Oops : testingagain OK : test Oops : mystuff Oops : interior Oops : third Oops : other Oops : something</pre> <p>Without a doubt, this is not exactly what you want and I probably goofed up some scoping rules of Coldfusion. But I think this will give you some insight in how to solve your problem properly. I think the code is pretty self explanatory, but if this is not the case, don't hesitate to ask for clarification.</p> <p>HTH</p>
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    1. POOnce grammar is complete, what's the best way to walk an ANTLR v4 tree?
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    1. USBart Kiers
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    1. COThis is an incredibly thorough answer but is a lot to digest. I'll be back in a few days =p.
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    2. CONo problem @Nucleon. Again: feel free to ask for clarification if I passed over certain aspects too quickly.
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    3. COHint: `ParseTreeWalker.DEFAULT.walk(...)`
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      1. USSam Harwell
 

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