private IArmString ParseFullExpression(ref ArmExpressionTokenizer tokenizer)
{
Expect(ref tokenizer, ArmExpressionTokenType.OpenBracket);
IArmString wholeExpression = ParseInnerExpression(ref tokenizer, noLiteral: true);
Expect(ref tokenizer, ArmExpressionTokenType.CloseBracket);
Expect(ref tokenizer, ArmExpressionTokenType.EOF);
return(wholeExpression);
}
private ArmExpressionToken Expect(ref ArmExpressionTokenizer tokenizer, ArmExpressionTokenType expectedTokenType)
{
ArmExpressionToken token = tokenizer.NextToken();
if (token.Type != expectedTokenType)
{
throw Error($"Expected token of type '{expectedTokenType}' but instead got '{token}' at index {tokenizer.PreviousIndex} in input '{tokenizer.Input}'");
}
return(token);
}
private ArmOperation ParseIdentifierExpression(ref ArmExpressionTokenizer tokenizer, ArmExpressionIdentifierToken identifier)
{
ArmExpressionToken token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.OpenParen:
ArmOperation expression = ParseCallExpression(ref tokenizer, identifier);
return(ParseDotExpression(ref tokenizer, expression));
default:
throw Error($"Expected a token of type '{ArmExpressionTokenType.OpenParen}' but instead got '{token}' in '{tokenizer.Input}' at index '{tokenizer.PreviousIndex}'");
}
}
private IArmString ParseInnerExpression(ref ArmExpressionTokenizer tokenizer, bool noLiteral = false)
{
ArmExpressionToken token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.String:
if (noLiteral)
{
throw Error($"Expected a literal token but found a string in '{tokenizer.Input}' at index {tokenizer.PreviousIndex}");
}
return(new ArmStringLiteral(token.CoerceToString()));
case ArmExpressionTokenType.Identifier:
return(ParseIdentifierExpression(ref tokenizer, (ArmExpressionIdentifierToken)token));
default:
throw Error($"Expected an expression token but found '{token}' in '{tokenizer.Input}' at index {tokenizer.PreviousIndex}");
}
}
private ArmOperation ParseDotExpression(ref ArmExpressionTokenizer tokenizer, ArmOperation lhs)
{
ArmExpressionToken token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.Dot:
token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.Identifier:
return(ParseDotExpression(ref tokenizer, new ArmMemberAccessExpression(lhs, new ArmStringLiteral(((ArmExpressionIdentifierToken)token).Identifier))));
default:
throw Error($"Expected token of type '{ArmExpressionTokenType.Identifier}' after '.' but instead got '{token}' at index {tokenizer.PreviousIndex} in input '{tokenizer.Input}'");
}
default:
tokenizer.UngetToken(token);
return(lhs);
}
}
private ArmOperation ParseCallExpression(ref ArmExpressionTokenizer tokenizer, ArmExpressionIdentifierToken identifier)
{
var arguments = new List <ArmExpression>();
ArmExpressionToken token;
bool sawCloseParen = false;
while (!sawCloseParen)
{
token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.Identifier:
arguments.Add(ParseIdentifierExpression(ref tokenizer, (ArmExpressionIdentifierToken)token));
break;
case ArmExpressionTokenType.String:
arguments.Add(new ArmStringLiteral(token.CoerceToString()));
break;
case ArmExpressionTokenType.Integer:
arguments.Add(new ArmIntegerLiteral(token.CoerceToLong()));
break;
case ArmExpressionTokenType.Boolean:
arguments.Add(ArmBooleanLiteral.FromBool(token.CoerceToBool()));
break;
case ArmExpressionTokenType.CloseParen:
if (arguments.Count == 0)
{
sawCloseParen = true;
continue;
}
goto default;
default:
throw Error($"Expected an expression but instead got '{token}' in input '{tokenizer.Input}' at index {tokenizer.PreviousIndex}");
}
token = tokenizer.NextToken();
switch (token.Type)
{
case ArmExpressionTokenType.Comma:
break;
case ArmExpressionTokenType.CloseParen:
sawCloseParen = true;
break;
default:
throw Error($"Expected an expression delimiter but instead got '{token}' in input '{tokenizer.Input}' at index {tokenizer.PreviousIndex}");
}
}
if (identifier.Identifier.Is(ParametersFunction))
{
return(new ArmParameterReferenceExpression((IArmString)arguments[0]));
}
if (identifier.Identifier.Is(VariablesFunction))
{
return(new ArmVariableReferenceExpression((IArmString)arguments[0]));
}
return(new ArmFunctionCallExpression(new ArmStringLiteral(identifier.Identifier), arguments.ToArray()));
}
private IArmString ParseWithTokenizer(string s)
{
var tokenizer = new ArmExpressionTokenizer(s);
return(ParseFullExpression(ref tokenizer));
}
