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copied!<p>I think your principal problem is that you failed to define a subtree constructor in your object subgrammar. (EDIT: OP says he left the semantic actions for <strong>object</strong> out of his example text. That doesn't change the following answer).</p> <p>You probably have to lookup up the objects in the order encountered, too. Maybe you intended:</p> <pre><code>primary_expression : constant_value { $$ = $1; } | '(' expression ')' { $$ = $2; } | list_initialization { $$ = $1; } | function_call { $$ = $1; } | object { $$ = $1; } ; object : IDENTIFIER { $$ = LookupVariableOrObject( yytext ); } | object ARROW IDENTIFIER { $$ = LookupSubobject( $1, yytext ); } ; </code></pre> <p>I assume that if one encounters an identifier X by itself, your default interpretation is that it is a variable name. But, if you encounter X -> Y, then even if X is a variable name, you want the <em>object</em> X with subobject Y. </p> <p>What LookupVarOrObject does is to lookup the <em>leftmost</em> identifier encountered to see if it is variable (and return essentially the same value as idlookup which must produce an AST node of type AST_VAR), or see if it is valid object name, and return an AST node marked as an AST_OBJ, or complain if the identifier isn't one of these.</p> <p>What LookupSuboject does, is to check its left operand to ensure it is an AST_OBJ (or an AST_VAR whose name happens to be the same as that of an object). and complain if it is not. If it is, then its looks up the yytext-child object of the named AST_OBJ.</p> <p>EDIT: Based on discussion comments in another answer, right-recursion in the OP's original grammar might be problematic if the OP's semantic checks inspect global lexer state (yytext). This solution is left-recursive and won't run afoul of that particular trap.</p>

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