private static AstNode ParseMatch(TokenStream stream)
{
MatchExpression expr = new MatchExpression (stream.Location);
stream.Expect (TokenClass.Keyword, "match");
expr.Add (ParseExpression (stream));
stream.Expect (TokenClass.OpenBrace);
while (stream.Accept (TokenClass.Keyword, "case")) {
AstNode condition = null;
AstNode pattern = ParsePattern (stream);
if (stream.Accept (TokenClass.Keyword, "when")) {
condition = ParseExpression (stream);
}
stream.Expect (TokenClass.Operator, "=>");
AstNode value = ParseExpression (stream);
expr.Children.Add (new CaseExpression (pattern.Location, pattern, condition, value));
}
stream.Expect (TokenClass.CloseBrace);
return expr;
}
public void Accept(MatchExpression match)
{
match.VisitChildren (functionCompiler);
}
public override void Accept (MatchExpression match)
{
AstNode value = match.Children [0];
value.Visit (this);
int temporary = methodBuilder.CreateTemporary ();
methodBuilder.EmitInstruction (match.Location, Opcode.StoreLocal, temporary);
PatternCompiler compiler = new PatternCompiler (symbolTable, methodBuilder,
temporary,
this);
IodineLabel nextLabel = methodBuilder.CreateLabel ();
IodineLabel endLabel = methodBuilder.CreateLabel ();
for (int i = 1; i < match.Children.Count; i++) {
if (i > 1) {
methodBuilder.MarkLabelPosition (nextLabel);
nextLabel = methodBuilder.CreateLabel ();
}
CaseExpression clause = match.Children [i] as CaseExpression;
clause.Pattern.Visit (compiler);
methodBuilder.EmitInstruction (match.Location, Opcode.JumpIfFalse, nextLabel);
if (clause.Condition != null) {
clause.Condition.Visit (this);
methodBuilder.EmitInstruction (match.Location, Opcode.JumpIfFalse, nextLabel);
}
clause.Value.Visit (this);
methodBuilder.EmitInstruction (match.Location, Opcode.Jump, endLabel);
}
methodBuilder.MarkLabelPosition (endLabel);
}
public override void Accept (MatchExpression match)
{
errorLog.AddError (ErrorType.ParserError, match.Location,
"match expression can not exist inside pattern!");
}
public virtual void Accept(MatchExpression match)
{
}
public void Accept(MatchExpression match)
{
match.VisitChildren (this);
}
public void Accept(MatchExpression match)
{
FunctionAnalyser visitor = new FunctionAnalyser (errorLog, symbolTable);
match.Visit (visitor);
}
public void Accept(MatchExpression match)
{
}