--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stage3/lvalue_check.hh	Wed Aug 22 16:46:17 2012 +0200
@@ -0,0 +1,141 @@
+/*
+ *  matiec - a compiler for the programming languages defined in IEC 61131-3
+ *
+ *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)
+ *  Copyright (C) 2012       Manuele Conti  (conti.ma@alice.it)
+ *
+ *
+ *  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 3 of the License, or
+ *  (at your 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 <http://www.gnu.org/licenses/>.
+ *
+ *
+ * This code is made available on the understanding that it will not be
+ * used in safety-critical situations without a full and competent review.
+ */
+
+/*
+ * An IEC 61131-3 compiler.
+ *
+ * Based on the
+ * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
+ *
+ */
+
+#include <vector>
+#include "../absyntax_utils/absyntax_utils.hh"
+#include "datatype_functions.hh"
+
+
+/* Expressions on the left hand side of assignment statements have aditional restrictions on their datatype.
+ * For example, they cannot be literals, CONSTANT type variables, function invocations, etc...
+ * This class wil do those checks.
+ * 
+ * Note that assignment may also be done when passing variables to OUTPUT or IN_OUT function parameters,so we check those too.
+ */
+
+
+
+class lvalue_check_c: public iterator_visitor_c {
+
+  private:
+    search_varfb_instance_type_c *search_varfb_instance_type;
+    search_var_instance_decl_c *search_var_instance_decl;
+    search_base_type_c search_base_type;
+    int error_count;
+    int current_display_error_level;
+    std::vector <token_c *> control_variables;
+    symbol_c *current_il_operand;
+
+    void verify_is_lvalue              (symbol_c *lvalue);
+    void check_assignment_to_controlvar(symbol_c *lvalue);
+    void check_assignment_to_output    (symbol_c *lvalue);
+    void check_assignment_to_constant  (symbol_c *lvalue);
+    void check_assignment_to_expression(symbol_c *lvalue);
+    void check_formal_call   (symbol_c *f_call, symbol_c *f_decl);
+    void check_nonformal_call(symbol_c *f_call, symbol_c *f_decl);
+
+
+  public:
+    lvalue_check_c(symbol_c *ignore);
+    virtual ~lvalue_check_c(void);
+    int get_error_count();
+
+    /**************************************/
+    /* B 1.5 - Program organisation units */
+    /**************************************/
+    /***********************/
+    /* B 1.5.1 - Functions */
+    /***********************/
+    void *visit(function_declaration_c *symbol);
+
+    /*****************************/
+    /* B 1.5.2 - Function blocks */
+    /*****************************/
+    void *visit(function_block_declaration_c *symbol);
+
+    /**********************/
+    /* B 1.5.3 - Programs */
+    /**********************/
+    void *visit(program_declaration_c *symbol);
+
+    /****************************************/
+    /* B.2 - Language IL (Instruction List) */
+    /****************************************/
+    /***********************************/
+    /* B 2.1 Instructions and Operands */
+    /***********************************/
+    void *visit(il_instruction_c *symbol);
+    void *visit(il_simple_operation_c *symbol);
+    void *visit(il_function_call_c *symbol);
+    void *visit(il_fb_call_c *symbol);
+    void *visit(il_formal_funct_call_c *symbol);
+
+    /*******************/
+    /* B 2.2 Operators */
+    /*******************/
+    void *visit(ST_operator_c *symbol);
+    void *visit(STN_operator_c *symbol);
+    void *visit(S_operator_c *symbol);
+    void *visit(R_operator_c *symbol);
+
+    /***************************************/
+    /* B.3 - Language ST (Structured Text) */
+    /***************************************/
+    /***********************/
+    /* B 3.1 - Expressions */
+    /***********************/
+    void *visit(function_invocation_c *symbol);
+
+    /*********************************/
+    /* B 3.2.1 Assignment Statements */
+    /*********************************/
+    void *visit(assignment_statement_c *symbol);
+
+    /*****************************************/
+    /* B 3.2.2 Subprogram Control Statements */
+    /*****************************************/
+    void *visit(fb_invocation_c *symbol);
+
+    /********************************/
+    /* B 3.2.4 Iteration Statements */
+    /********************************/
+    void *visit(for_statement_c *symbol);
+
+}; /* lvalue_check_c */
+
+
+
+
+
+
+