private SourceStream(SourceStream parent, int index, int count)
{
_content = parent._content + index;
_count = count;
_index = 0;
_parent = parent;
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public grammar.SourceStream GetSource()
{
lock (_syncpoint)
{
if (_sourceStream is null)
{
var info = new FileInfo(_path);
if (!info.Exists)
{
throw new FileNotFoundException("File not found", _path);
}
using (var stream = info.Open(FileMode.Open, FileAccess.Read, FileShare.Read))
using (var reader = new StreamReader(stream))
{
string content = reader.ReadToEnd();
var array = content.ToCharArray();
_sourceStream = new grammar.SourceStream(array);
}
}
return(_sourceStream);
}
}
void IDisposable.Dispose()
{
lock (_syncpoint)
{
if (_sourceStream is IDisposable disposable)
{
disposable.Dispose();
_sourceStream = null;
}
}
}
static bool MatchAny(SourceStream source, GrammarParserDelegate[] parsers, out BaseType result)
{
for (int i = 0; i < parsers.Length; i += 1)
{
if (parsers[i](source, out result))
{
return(true);
}
}
result = null;
return(false);
}
public bool MatchStruct(SourceStream source, out BaseType result)
{
StructType value;
if (Match(source, out value))
{
result = value;
return(true);
}
result = null;
return(false);
}
public bool ImportFile(SourceStream source, out SymbolTable result)
{
result = null;
if (!source.IsValid())
{
return(false);
}
var slice = source.GetSlice();
if (!slice.MatchString(KeywordImport))
{
return(false);
}
SkipCommentsAndWhitespace(slice);
if (!slice.MatchString(TokenImportFirst))
{
throw new ParseError($"Expected '{TokenImportFirst}'.", slice);
}
int start = slice.Index();
int count = slice.FindNext(TokenImportFinal);
if (count < 0)
{
throw new ParseError($"Expected '{TokenImportFinal}'.", slice);
}
if (!slice.ReadAbsolute(start, count, out string path))
{
throw new ParseError("Unable to read inlcude path.", slice);
}
slice.MoveBy(path.Length);
if (!slice.MatchString(TokenImportFinal))
{
throw new ParseError($"Expected '{TokenImportFinal}'.", slice);
}
result = GetSymbolsFromFile(path);
source.Join(slice);
return(true);
}
static bool SkipCommentsAndWhitespace(SourceStream source)
{
if (!source.IsValid())
{
return(false);
}
var slice = source.GetSlice();
while (true)
{
slice.SkipWhitespace();
if (slice.MatchString(TokenCommentBlockFirst))
{
int index = slice.FindNext(TokenCommentBlockFinal);
if (index < 0)
{
slice.MoveBy(-TokenCommentBlockFirst.Length);
throw new ParseError($"unterminated comment, expected to find '{TokenCommentBlockFinal}'.", slice);
}
slice.MoveBy(index + TokenCommentBlockFinal.Length);
}
else if (slice.MatchString(TokenCommentLineFirst))
{
int index = slice.FindNext(TokenCommandLineFinal);
if (index < 0)
{
if (index < 0)
{
slice.MoveBy(-TokenCommentLineFirst.Length);
throw new ParseError($"unterminated comment, expected to find '\\n'.", slice);
}
}
slice.MoveBy(index + TokenCommandLineFinal.Length);
}
else
{
source.Join(slice);
return(true);
}
}
}
public SourceSpan Join(SourceStream slice)
{
if (slice is null)
{
throw new ArgumentNullException(nameof(slice));
}
if (slice._parent != this)
{
throw new ArgumentException($"Can only join children to parent `{nameof(SourceStream)}` instances.", nameof(slice));
}
if (slice._index == 0)
{
return(new SourceSpan(this, _index, 0));
}
var span = new SourceSpan(this, _index, slice._index - 1);
_index += slice._index;
return(span);
}
public SourceSpan(SourceStream source, int index, int count)
{
_count = count;
_index = index;
_source = source;
}
public ParseError(string message, SourceStream source)
: base(format_message(message, source))
{
}
static string format_message(string message, SourceStream source)
{
return($"parse error: {message}\n\n {source.AsString()}");
}
public bool Match(SourceStream source, out StructType result)
{
result = null;
if (!source.IsValid())
{
return(false);
}
var slice = source.GetSlice();
if (!slice.MatchString(KeywordStruct))
{
return(false);
}
SkipCommentsAndWhitespace(slice);
if (!slice.ReadWord(out string name))
{
throw new ParseError("expected struct name.", slice);
}
if (!name.IsNameLegal())
{
slice.MoveBy(-name.Length);
throw new ParseError($"'{name}' is not a legal struct name.", slice);
}
SkipCommentsAndWhitespace(slice);
if (!slice.MatchString(TokenStructFirst))
{
throw new ParseError($"expeceted '{TokenStructFirst}'.", slice);
}
var members = new TypeSet();
while (slice.IsValid())
{
SkipCommentsAndWhitespace(slice);
if (slice.MatchString(TokenStructFinal))
{
break;
}
if (!Match(slice, out MemberType member))
{
throw new ParseError("failed to parse member.", slice);
}
members.Add(member.Ordinal(), member);
}
var span = source.Join(slice);
result = new StructType(name, members, span);
return(true);
}
