private void endLineSoft()
{
if (currentLine.words.Count > 0)
{
var line = new SmeltLine(text.From(currentLine.words[0].Fragment.Start)
.To(currentLine.words.Last().Fragment.End),
currentLine.words.ToImmutableList());
currentBlock.lines.Add(line);
currentLine = new BuildingLine(currentBlock);
}
}
internal SmeltFile Parse()
{
currentBlock = new BuildingBlock(0, null);
currentLine = new BuildingLine(currentBlock);
while (index < sourceText.Length)
{
var ch = sourceText[index];
switch (state)
{
case State.InLine:
if (ch == '{')
{
currentBlock = new BuildingBlock(index, currentLine);
currentLine = new BuildingLine(currentBlock);
}
else if (ch == '[')
{
currentLiteral = new BuildingLiteral(index);
state = State.InLiteral;
}
else if (ch == '#')
{
state = State.InComment;
}
else if (ch == ';')
{
// This is a 'hard' end of line, as opposed to endLineSoft()
// A semicolon always causes a line to actually exist, even if it's empty
// { } is a block with no lines in it, but { ; } is a block with one (empty) line in it.
// Similarly, { hello ; ; world } is a block with three lines in it (a line containing "hello", an empty line, and
// a line containing "world").
// The boundaries of the fragments look like this:
// { hello ; ; world ; } { is it ; me ; ; you're looking for }
// ------- - ------- ------- ---- - ------------------
int start = currentLine.words.Count == 0 ? index : currentLine.words[0].Fragment.Start;
currentBlock.lines.Add(new SmeltLine(text.From(start).To(index), currentLine.words.ToImmutableList()));
currentLine = new BuildingLine(currentBlock);
}
else if (ch == '}')
{
endLineSoft();
if (currentBlock.inLine == null)
{
throw new ApplicationException("Close block that was not open"); // FIXME should be a parse exception using the line position
}
currentLine = currentBlock.inLine;
currentLine.words.Add(new SmeltBlock(text.From(currentBlock.start).To(index), currentBlock.lines.ToImmutableList()));
currentBlock = currentLine.inBlock;
}
else if (ch == ']')
{
throw new ApplicationException("Illegal character"); // FIXME Should error more usefully
}
else if (char.IsWhiteSpace(ch))
{
// do nothing
}
else
{
atomStart = index;
state = State.InAtom;
}
break;
case State.InComment:
if (ch == '\n' || ch == '\r')
{
state = State.InLine;
}
else
{
// do nothing, continue parsing the comment
}
break;
case State.InLiteral:
if (ch == '[')
{
currentLiteral.fragmentTo(text, index);
state = State.InLiteralEscape;
}
else if (ch == ']')
{
currentLiteral.fragmentTo(text, index);
currentLine.words.Add(new SmeltLiteral(text.From(currentLiteral.start).To(index), currentLiteral.fragments.ToImmutableList()));
state = State.InLine;
}
else
{
// do nothing
}
break;
case State.InLiteralEscape:
if (ch == '#')
{
state = State.InLiteralComment;
}
else if (ch == '[' || ch == ']')
{
state = State.InLiteral;
}
else
{
throw new ApplicationException("Unexpected escaped character"); // FIXME
}
break;
case State.InLiteralComment:
if (ch == '\r' || ch == '\n')
{
currentLiteral.fragmentStart = index;
state = State.InLiteral;
}
else
{
// do nothing
}
break;
case State.InAtom:
if (ch == '[' || ch == ']')
{
throw new ApplicationException("Illegal character"); // FIXME error more usefully
}
else if (ch == '{' || ch == '}' || ch == ';' || char.IsWhiteSpace(ch))
{
index--;
currentLine.words.Add(new SmeltAtom(text.From(atomStart).To(index)));
state = State.InLine;
}
else
{
// do nothing, continue parsing the atom
}
break;
}
index++;
}
switch (state)
{
case State.InAtom:
currentLine.words.Add(new SmeltAtom(text.From(atomStart).To(index - 1)));
break;
case State.InLiteral:
case State.InLiteralEscape:
throw new ApplicationException("Unterminated string literal"); // FIXME
}
endLineSoft();
if (currentBlock.inLine != null)
{
throw new ApplicationException("Unterminated block"); // FIXME
}
return(new SmeltFile(text, currentBlock.lines.ToImmutableList()));
}
internal BuildingBlock(int start, BuildingLine inLine)
{
this.start = start;
this.inLine = inLine;
}