NAME

  Math::Expr::Opp - Represents one operation in the parsed expression 
                    tree

SYNOPSIS

  require Math::Expr::Opp;
  require Math::Expr::Var;
  require Math::Expr::Num;
  
  # To represent the expression "x+7":
  $n=new Math::Expr::Opp("+");
  $n->SetOpp(0,new Math::Expr::Var("x"));
  $n->SetOpp(1,new Math::Expr::Num(7));
  print $n->tostr . "\n";

DESCRIPTION

  Used by the Math::Expr to represent algebraic expressions. This class 
  represents one operation or function with a set of operands, which 
  in turn can be other Math::Expr::Opp objects. And in that way we are 
  able to represent entire expression.

  Operations like a+b and functions like sin(a) or f(a,b) are all 
  represented by this kind of objects with "+", "sin" and "f" as the
  operation- or function names and Math::Expr::Var(a) and 
  Math::Expr::Var(b) as operands (only a in the sin example).

METHODS

$e=new Math::Expr::Opp($name,$db)

  Creates a new operation object with the operation- or function-name 
  $name. Using the operations defined in $db. See 
  L<Math::Expr::OpperationDB> for more info.

$e->SetOpp($i, $v)

  Sets operand number $i to $v.

$e->Opp($i)

  Returns operand to number $i.

$e->tostr

  Returns a string representation of the entire expression to be 
  used for debugging.

$e->strtype

  Returns a string representation of this expressions entire type, 
  without simplifying it. In the same notation as the tostr method.

$n->Simplify

  Simplifys the expression to some normal from.

$n->BaseType

  Returns a string type of this expression simplifyed as much as 
  possible.

$n->SubMatch($rules,$match)

  Tries to match $rules to this expretions and adds the substitutions 
  needed to $match.Returns 1 if the match excists and the substitutions 
  needed can coexcist with those already in $match otherwise 0.

$n->Match($rules)

  Tries to match $rules to this expretions and to all its subexpretions. 
  Returns a MatchSet object specifying where the matches ocored and what 
  substitutions they represent.

$n->Subs($vars)

  Substitues all variables in the expretion with there vaules in $vars.

$n->Copy

Returns a copy of this object.

$n->Breakable

  Used by the parser to indikate if this object was created using 
  parantesis or if he should break it up to preserve the rules of order 
  between the diffrent opperations.

$n->Find($pos)

  Returns an object pointer to the subexpression represented by the 
  string $pos.

$n->Set($pos, $val)

  Replaces the subexpression at position $pos with $val.

AUTHOR

  Hakan Ardo <hakan@debian.org>