/// <summary>
/// Parses a conditional statement.
/// </summary>
public ParseResult ParseConditional(List <Token> tokens)
{
var node = new ConditionalNode();
var scopeCheck = new ScopeCheck();
for (int i = 0; i < tokens.Count; i++)
{
var token = tokens[i];
scopeCheck.Check(token);
if (token.Equals("?", TokenTypes.Punctuator) && scopeCheck.IsInScope)
{
SkipInfo skip = SkipFromTo("?", ":", tokens, i);
var conditionNode = ParseClean(tokens.GetRange(0, i));
var successNode = ParseClean(tokens.GetRange(i + 1, skip.Delta - 1));
var failNode = ParseClean(tokens.GetRange(skip.End + 1, tokens.Count - (skip.End + 1)));
node.Condition = conditionNode ?? throw new SkryptException("Syntax error, condition statement can't be empty");
node.Pass = successNode ?? throw new SkryptException("Syntax error, consequent statement can't be empty");
node.Fail = failNode ?? throw new SkryptException("Syntax error, alternative statement can't be empty");
return(new ParseResult {
Node = node, Delta = tokens.Count
});
}
}
_engine.ThrowError("Syntax error, conditional statement incomplete", tokens[0]);
return(null);
}
/// <summary>
/// Parses a list of tokens into an expression node
/// </summary>
public ParseResult Parse(List <Token> tokens)
{
var node = new Node();
var delta = 0;
var addDelta = 0;
var deltaOffset = 0;
var scopeCheck = new ScopeCheck();
var previousToken = default(Token);
if (tokens[0].Type == TokenTypes.EndOfExpression)
{
delta++;
deltaOffset = 1;
}
// Loop until we hit the end of an expression, or consumed all tokens.
while (true)
{
scopeCheck.Check(tokens[delta]);
if (scopeCheck.IsInScope && tokens[delta].Type == TokenTypes.EndOfExpression)
{
if (tokens[delta].Type == TokenTypes.EndOfExpression)
{
addDelta = 1;
break;
}
}
previousToken = tokens[delta];
delta++;
if (delta == tokens.Count)
{
break;
}
}
var returnNode = ParseClean(tokens.GetRange(deltaOffset, delta - deltaOffset));
returnNode = ExpressionOptimiser.OptimiseExpressionNode(returnNode, _engine);
delta += addDelta;
return(new ParseResult {
Node = returnNode, Delta = delta
});
}
/// <summary>
/// Parses individual arguments as expressions.
/// </summary>
public void SetArguments(List <List <Token> > arguments, List <Token> tokens)
{
var i = 0;
var buffer = new List <Token>();
var isFirst = true;
var scopeCheck = new ScopeCheck();
for (i = 0; i < tokens.Count; i++)
{
var token = tokens[i];
buffer.Add(token);
scopeCheck.Check(token);
// Only set arguments if they're not inside nested function calls.
if (scopeCheck.IsInScope)
{
if (token.Equals(",", TokenTypes.Punctuator))
{
isFirst = false;
// Arguments cannot be empty.
if (buffer.Count == 0)
{
_engine.ThrowError("Syntax error, missing tokens for argument.", tokens[i]);
}
buffer.RemoveAt(buffer.Count - 1);
arguments.Add(new List <Token>(buffer));
buffer.Clear();
}
// Reached the end of all argument tokens.
// All tokens from the start, or from the last ',' token are part of the last argument.
if (i == tokens.Count - 1)
{
// Arguments cannot be empty.
if (buffer.Count == 0 && !isFirst)
{
_engine.ThrowError("Syntax error, missing tokens for argument.", tokens[i]);
}
arguments.Add(new List <Token>(buffer));
buffer.Clear();
}
}
}
}
// Checks whether a list of tokens is a valid conditional statement.
private bool IsConditional(List <Token> tokens)
{
var isConditional = false;
var scopeCheck = new ScopeCheck();
for (int i = 0; i < tokens.Count; i++)
{
var token = tokens[i];
scopeCheck.Check(token);
if (token.Equals("?", TokenTypes.Punctuator) && scopeCheck.IsInScope)
{
isConditional = true;
SkipInfo skip = SkipFromTo("?", ":", tokens, i);
}
}
return(isConditional);
}
