/// <summary>
/// Evaluates the expression by appending all the sub-expressions.
/// </summary>
/// <returns></returns>
public static object EvalInterpolated(InterpolatedExpr expr)
{
if (expr.Expressions == null || expr.Expressions.Count == 0)
return string.Empty;
string total = "";
foreach (var exp in expr.Expressions)
{
if (exp != null)
{
var val = exp.Evaluate();
var text = "";
var lobj = (LObject)val;
text = lobj.GetValue().ToString();
total += text;
}
}
return new LString(total);
}
/// <summary>
/// Visits the function call expression tree
/// </summary>
/// <param name="exp"></param>
public object VisitInterpolated(InterpolatedExpr exp)
{
return null;
}
/// <summary>
/// Parses an interpolated token into a set of tokens making up an interpolated expression.
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
public Expr ParseInterpolatedExpression(Token t)
{
var iexp = new InterpolatedExpr();
// Convert each token in the interpolated string, need to convert it into
// it's own expression.
var tokens = t.Value as List<TokenData>;
foreach (var tokenData in tokens)
{
var token = tokenData.Token;
Expr exp = null;
// 1. true / false / "name" / 123 / null;
if (token.IsLiteralAny())
{
exp = token == Tokens.Null
? new ConstantExpr(LObjects.Null)
: new ConstantExpr(TokenHelper.ConvertToLangLiteral(token));
this.SetupContext(exp, tokenData);
_state.ExpressionCount++;
}
// 2. ${first + 'abc'} or ${ result / 2 + max }
else if (token.Kind == TokenKind.Multi)
{
var tokenIterator = new TokenIterator();
var tokens2 = token.Value as List<TokenData>;
tokenIterator.Init(tokens2, 1, 100);
tokenIterator.Advance();
var exisiting = _tokenIt;
// a. Temporarily set the token iterator for the parser to the one for the interpolation.
_tokenIt = tokenIterator;
// b. Now parse only the tokens supplied.
exp = ParseExpression(null);
// c. Reset the token iterator to the global one for the entire script.
_tokenIt = exisiting;
}
iexp.Add(exp);
}
_tokenIt.Advance();
return iexp;
}