/// <summary>
/// Exit a parse tree produced by <see cref="CalcParser.exp"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void ExitExp([NotNull] CalcParser.ExpContext context)
{
}
/// <summary>
/// Visit a parse tree produced by <see cref="CalcParser.exp"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public virtual Result VisitExp([NotNull] CalcParser.ExpContext context)
{
return(VisitChildren(context));
}
public override Calc_node VisitExp([NotNull] CalcParser.ExpContext context)
{
int i = context.ChildCount;
if (i == 1)
{
//node log_exp trig_exp
var subtree = context.GetChild(0);
return(Visit(subtree));
}
else if (i == 2)
{
// LeftParen RightParen 空括号节点
if (context.LeftParen() != null)
{
return(new Bracket_node());
}
else if (context.Minus() != null)
{
Calc_node absolute_val = Visit(context.children[1]);
absolute_val.fresult = -absolute_val.fresult;
absolute_val.result = -absolute_val.result;
return(absolute_val);
}
else
{
return(null);
}
}
else if (i == 3)
{
var child = context.GetChild(1);
if (child.ChildCount == 0)
{
// + - * / ^
Binary_node node = new Binary_node();
switch (child.GetText())
{
case "+":
node.op = Binary_node.Operator.ADD;
break;
case "-":
node.op = Binary_node.Operator.MINUS;
break;
case "*":
node.op = Binary_node.Operator.MULTI;
break;
case "/":
node.op = Binary_node.Operator.DIVIDE;
break;
case "^":
node.op = Binary_node.Operator.EXPO;
break;
}
node.node1 = Visit(context.GetChild(0));
node.node2 = Visit(context.GetChild(2));
return(node);
}
else
{
//(exp)
return(new Bracket_node
{
internal_node = Visit(context.GetChild(1))
});
}
}
else
{
// will not be executed Unless there is a error
throw(new ApplicationException("unexpected ChildCount of ExpContext"));
}
}