/// <summary>
/// Throw exception if EOF reached.
/// </summary>
private static void ThowIfEof(this ICharInput input)
{
if (input.IsEof())
{
throw new ParsingException("unexpected end of file", input.Position);
}
}
/// <summary>
/// Consume leading spaces.
/// </summary>
private static ICharInput ConsumeSpaces(this ICharInput input)
{
while (char.IsWhiteSpace(input.Current))
{
input = input.GetNext();
}
return(input);
}
private static ParseResult <QuotedOrNonquotedValueNode> ParseNonquotedValue(ICharInput input)
{
var res = input.ConsumeWhileNonSpace();
return
(CreateResult(
new QuotedOrNonquotedValueNode(res.Result, input.Position, res.InputRest.Position - input.Position, false),
res.InputRest));
}
private static ICharInput ConsumeChar([NotNull] this ICharInput input, char charToConsume)
{
if (input.Current != charToConsume)
{
throw new ParsingException(
$"'{charToConsume}' expected, but '{input.Current}' found",
input.Position);
}
return(input.GetNext());
}
/// <summary>
/// Consume single char.
/// </summary>
private static ICharInput ConsumeChar(this ICharInput input, char charToConsume)
{
if (input.Current != charToConsume)
{
throw new ParsingException(
"'{0}' expected, but '{1}' found".FormatWith(charToConsume, input.Current),
input.Position);
}
return(input.GetNext());
}
private static ParseResult <OptionNode> ParseOption(ICharInput input)
{
var startPos = input.Position;
if (!IsOptionPrefix(input.Current))
{
throw new ParsingException("invalid option prefix '{0}'");
}
input = input.GetNext();
var name =
input.ConsumeWhile(
c =>
c != CharInput.EOF &&
!char.IsWhiteSpace(c) &&
c != '=' &&
c != '+' &&
c != '-');
if (name.Result.Length == 0)
{
throw new ParsingException("option name expected", input.Position);
}
var nextChar = name.InputRest.Current;
if (nextChar == '+' || nextChar == '-')
{
return
(CreateResult(
new OptionNode(name.Result, startPos, name.InputRest.Position - startPos + 1, nextChar == '+'),
name.InputRest.GetNext()));
}
if (nextChar == '=')
{
var value = ParseQuotedOrNonquotedValue(name.InputRest.GetNext());
if (value.Result.Text.Length == 0)
{
throw new ParsingException(
"option '{0}' value not specified".FormatWith(name.Result),
value.Result.Position);
}
return
(new ParseResult <OptionNode>(
new OptionNode(name.Result, startPos, value.InputRest.Position - startPos, value.Result),
value.InputRest));
}
return
(CreateResult(
new OptionNode(name.Result, startPos, name.InputRest.Position - startPos),
name.InputRest));
}
/// <summary>
/// Consume while space character or end of file reached.
/// </summary>
private static ParseResult <string> ConsumeWhileNonSpace(this ICharInput input)
{
var sb = new StringBuilder();
while (!input.IsEof() && !char.IsWhiteSpace(input.Current))
{
sb.Append(input.Current);
input = input.GetNext();
}
return(new ParseResult <string>(sb.ToString(), input));
}
private static ParseResult <string> ConsumeWhile([NotNull] this ICharInput input, char stopChar)
{
var sb = new StringBuilder();
while (input.Current != stopChar)
{
input.ThowIfEof();
sb.Append(input.Current);
input = input.GetNext();
}
return(new ParseResult <string>(sb.ToString(), input));
}
/// <summary>
/// Consume while predicate is true.
/// </summary>
private static ParseResult <string> ConsumeWhile(this ICharInput input, Func <char, bool> predicate)
{
var sb = new StringBuilder();
while (predicate(input.Current))
{
input.ThowIfEof();
sb.Append(input.Current);
input = input.GetNext();
}
return(new ParseResult <string>(sb.ToString(), input));
}
private static ParseResult <CommandNode> ParseCommand(ICharInput input)
{
var res = input.ConsumeWhileNonSpace();
if (input.IsEof())
{
return(null);
}
return
(CreateResult(
new CommandNode(res.Result, input.Position, res.InputRest.Position - input.Position),
res.InputRest));
}
private static ParseResult <QuotedOrNonquotedValueNode> ParseQuotedValue(ICharInput input)
{
var startPos = input.Position;
input = input.ConsumeChar(_quota);
var res = input.ConsumeWhile(_quota);
input = res.InputRest.ConsumeChar(_quota);
return
(CreateResult(
new QuotedOrNonquotedValueNode(res.Result, startPos, input.Position - startPos, true),
input));
}
private static ParseResult <CommandOrOption> ParseCommandOrOption(ICharInput input)
{
input = input.ConsumeSpaces();
if (IsOptionPrefix(input.Current))
{
var option = ParseOption(input);
return(new ParseResult <CommandOrOption>(new CommandOrOption(option.Result), option.InputRest));
}
var command = ParseCommand(input);
return
(command == null
? null
: new ParseResult <CommandOrOption>(new CommandOrOption(command.Result), command.InputRest));
}
/// <summary>
/// Consume many elements.
/// </summary>
private static ParseResult <T[]> ConsumeTillEof <T>(
this ICharInput input,
Func <ICharInput, ParseResult <T> > consumer)
{
var list = new List <T>();
while (true)
{
var res = consumer(input);
if (res == null)
{
break;
}
list.Add(res.Result);
input = res.InputRest;
}
return(new ParseResult <T[]>(list.ToArray(), input));
}
///<summary>
/// Initialize instance with result.
///</summary>
public ParseResult([NotNull] T result, [NotNull] ICharInput inputRest)
{
Result = result;
InputRest = inputRest;
}
private static ParseResult <T> CreateResult <T>([NotNull] T result, [NotNull] ICharInput inputRest) => new ParseResult <T>(result, inputRest);
private static ParseResult <T> CreateResult <T>(T result, ICharInput inputRest) => new ParseResult <T>(result, inputRest);
/// <summary> /// True, if end of file reached. /// </summary> private static bool IsEof([NotNull] this ICharInput input) => input.Current == CharInput.Eof;
/// <summary>
/// True, if end of file reached.
/// </summary>
private static bool IsEof(this ICharInput input)
{
return(input.Current == CharInput.EOF);
}
///<summary>
/// Initialize instance with result.
///</summary>
public ParseResult(T result, ICharInput inputRest)
{
Result = result;
InputRest = inputRest;
}
private static ParseResult <QuotedOrNonquotedValueNode> ParseQuotedOrNonquotedValue(ICharInput input)
{
return(input.Current == _quota?ParseQuotedValue(input) : ParseNonquotedValue(input));
}
private static ParseResult <T> CreateResult <T>(T result, ICharInput inputRest)
{
return(new ParseResult <T>(result, inputRest));
}
private static ParseResult <QuotedOrNonquotedValueNode> ParseQuotedOrNonquotedValue([NotNull] ICharInput input) => input.Current == _quota?ParseQuotedValue(input) : ParseNonquotedValue(input);