private bool HasMoreAmountCharacters(ParserContext context)
{
if (!context.Buffer.HasNext())
{
return(false);
}
if (NextCharacterIsValid(context))
{
return(true);
}
// When whitespace is next there are two cases:
//
// 1. Whitespace is being used to separate in the amount e.g. 1 1/2 grams, 1/4 - 1/3 cup
// 2. Whitespace is being used to separate the next token e.g. 1/2 cup milk, 2 grams flour
//
// We handle these by looking ahead past the space to see if there are further characters valid
// for an amount token - if not this is a single that the amount token is complete.
if (context.Buffer.IsWhitespace())
{
// Offset by 1 to skip the whitepsace at the current position.
var nextCharacters = context.Buffer.Peek(offset: 1, count: 1);
if (!nextCharacters.Any())
{
// When there's nothing after the whitespace then we definitely are done reading.
return(false);
}
var characterAfterWhitespace = nextCharacters.First();
// There's something after the whitespace, check if it is a valid amount token character.
return(ValidNextCharacterPredicates.Any(p => p(characterAfterWhitespace)));
}
return(false);
}
private bool NextCharacterIsValid(ParserContext context) => ValidNextCharacterPredicates.Any(p => context.Buffer.Matches(p));