.\" .\" UCSD p-System cross compiler .\" Copyright (C) 2011, 2012 Peter Miller .\" .\" This program is free software; you can redistribute it and/or modify .\" it under the terms of the GNU General Public License as published by .\" the Free Software Foundation; either version 2 of the License, or (at .\" you option) any later version. .\" .\" This program is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU .\" General Public License for more details. .\" .\" You should have received a copy of the GNU General Public License along .\" with this program. If not, see .\" .nf .ad l .hy 0 Miller, P. A. (2010) Factory Factory Factories
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The Assignment Problem: Left versus Right

There is a problem with the assignment expression.
expression
    : expression ASSIGN expression
        { $$ = context->expression_assignment($1, $3); }
    | IDENTIFIER
        { $$ = context->expression_identifier($1); }
    | etc etc
    ;

Let's play whack-a-mole.

void
translator::expression_assignment(expression *lhs, expression *rhs)
{
    expression_ldl *t1 = dynamic_cast<expression_ldl>(lhs)
    if (t1)
        return new expression_stl(t1->get_address(), rhs);
    expression_ldo *t2 = dynamic_cast<expression_ldo>(lhs)
    if (t2)
        return new expression_sro(t2->get_address(), rhs);

    etc etc etc

    yyerror("left hand side of assignment inappropriate");
    return new expression_error();
}
This is another imperative type-based dispatch.
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