/*
 * expr_ruby.tc - Expression example treecc input file for Ruby.
 *
 * Copyright (C) 2001, 2002  Southern Storm Software, Pty Ltd.
 *
 * Hacked by Peter Minten <silvernerd@users.sf.net>
 *
 * 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 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

%option lang = "Ruby"

%output "expr_ruby.rb"

/*
 * Include the following declarations in the ".rb" file.
 */
%{

class Eval_value
  Int_value = 0
  Float_value = 0
end

%}

/*
 * Define the type code that is associated with a node
 * in the syntax tree.  We use "error_type" to indicate
 * a failure during type inferencing.
 */
%enum Type_code =
{
	Error_type,
    Int_type,
    Float_type
}

/*
 * Define the node types that make up the syntax.
 */
%node Expression %abstract %typedef =
{
    %nocreate Type_code type = {Type_code::Error_type};
}

%node Binary Expression %abstract =
{
    Expression expr1;
    Expression expr2;
}

%node Unary Expression %abstract =
{
    Expression expr;
}

%node Intnum Expression =
{
	int num;
}

%node Floatnum Expression =
{
    float num;
}

%node Plus Binary
%node Minus Binary
%node Multiply Binary
%node Divide Binary
%node Power Binary
%node Negate Unary

%node Cast Expression =
{
	Type_code new_type;
	Expression expr;
}

/*
 * Define the "infer_type" operation as a non-virtual.
 */
%operation void InferType::infer_type(Expression e)

infer_type(Binary)
{
  infer_type(e.expr1)
  infer_type(e.expr2)

  if (e.expr1.type == Type_code::Error_type || e.expr2.type == Type_code::Error_type) then
    e.type = Type_code::Error_type
  elsif (e.expr1.type == Type_code::Float_type || e.expr2.type == Type_code::Float_type) then
    e.type = Type_code::Float_type
  else
    e.type = Type_code::Int_type
  end
}

infer_type(Unary)
{
  infer_type(e.expr)
  e.type = e.expr.type
}

infer_type(Intnum)
{
  e.type = Type_code::Int_type
}

infer_type(Floatnum)
{
  e.type = Type_code::Float_type
}

infer_type(Power)
{
  infer_type(e.expr1)
  infer_type(e.expr2)

  if (e.expr1.type == Type_code::Error_type || e.expr2.type == Type_code::Error_type) then
    e.type = Type_code::Error_type
  elsif (e.expr2.type != Type_code::Int_type) then
    p (e.getFilename() + ":" + e.getLinenum() + ": second argument to `^' is not an integer")
    e.type = Type_code::Error_type
  else
    e.type = e.expr1.type
  end
}

infer_type(Cast)
{
  infer_type(e.expr)

  if(e.expr.type != Type_code::Error_type)
    e.type = e.new_type
  else
    e.type = Type_code::Error_type
  end
}

/*
 * Define the "eval_expr" operation as a virtual.
 */
%operation %virtual eval_value eval_expr(Expression this)

eval_expr(Plus)
{
  # Evaluate the sub-Expressions
  eval_value value1 = expr1.eval_expr
  eval_value value2 = expr2.eval_expr

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value2, expr2.type, type)

  # Evaluate the operator 
  if (type == Type_code::Int_type) then
    value1.Int_value += value2.Int_value
  else
    value1.Float_value += value2.Float_value
  end

  # Return the result to the caller
  return value1
}

eval_expr(Minus)
{
  # Evaluate the sub-Expressions 
  eval_value value1 = expr1.eval_expr()
  eval_value value2 = expr2.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value2, expr2.type, type)

  # Evaluate the operator
  if(type == Type_code::Int_type) then
    value1.Int_value -= value2.Int_value
  else
    value1.Float_value -= value2.Float_value;
  end

  # Return the result to the caller
  return value1
}

eval_expr(Multiply)
{
  # Evaluate the sub-Expressions 
  eval_value value1 = expr1.eval_expr()
  eval_value value2 = expr2.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value2, expr2.type, type)

  # Evaluate the operator
  if(type == Type_code::Int_type) then
    value1.Int_value *= value2.Int_value
  else
    value1.Float_value *= value2.Float_value;
  end

  # Return the result to the caller
  return value1
}

eval_expr(Divide)
{
  # Evaluate the sub-Expressions 
  eval_value value1 = expr1.eval_expr()
  eval_value value2 = expr2.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value2, expr2.type, type)

  # Evaluate the operator
  if(type == Type_code::Int_type) then
    value1.Int_value -= value2.Int_value
  else
    value1.Float_value -= value2.Float_value;
  end

  # Return the result to the caller
  return value1
}

eval_expr(Power)
{
  # Evaluate the sub-Expressions 
  eval_value value1 = expr1.eval_expr()
  eval_value value2 = expr2.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value2, expr2.type, type)

  # Evaluate the operator
  if(type == Type_code::Int_type) then
    value1.Int_value = value1.Int_value ^ value2.Int_value
  else
    value1.Float_value = value1.Float_value ^ value2.Float_value;
  end

  # Return the result to the caller
  return value1
}

eval_expr(Negate)
{
  # Evaluate the sub-Expression 
  eval_value value = expr.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value1, expr1.type, type)
  Coerce.coerce(value, expr.type, type)

  # Evaluate the operator
  if(type == Type_code::Int_type) then
    value.Int_value = -1 * value.Int_value
  else
    value.Float_value = -1 * value.Float_value;
  end

  # Return the result to the caller
  return value
}

eval_expr(Cast)
{
  # Evaluate the sub-Expression
  eval_value value = expr.eval_expr()

  # Coerce to the common type
  Coerce.coerce(value, expr.type, type)

  # Return the result to the caller
  return value
}

eval_expr(Intnum)
{
  value = eval_value.new
  value.Int_value = num
  return value
}

eval_expr(Floatnum)
{
  value = eval_value.new
  value.Float_value = num
  return value
}

/*
 * Define the "coerce" operation as an inline non-virtual.
 */
%operation %inline void Coerce::coerce
				(value, [Type_code from], [Type_code to])

coerce(Int_type, Float_type)
{
  value.Float_value = value.Int_value.to_f;
}

coerce(Float_type, Int_type)
{
  value.Int_value = value.Float_value.to_i;
}

coerce(Type_code, Type_code)
{
  # Nothing to do here
}