public static LinkedListNode <Lexeme> TryParse(LinkedListNode <Lexeme> lexemes, out FnParam resultNode)
{
resultNode = null;
var nextLexeme = Type.TryParse(lexemes, out Type type);
if (type == null)
{
return(lexemes);
}
if (nextLexeme.Value.Type != LT.IDENT)
{
throw new Exception($"Missing function argument name at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
Lexeme token = nextLexeme.Value;
nextLexeme = nextLexeme.Next;
if (nextLexeme.Value.Type == LT.OP_ASSIGN)
{
nextLexeme = nextLexeme.Next;
nextLexeme = Literal.TryParse(nextLexeme, out Literal lit);
if (lit == null)
{
throw new Exception($"Missing default value after assignment operator in function arguments list at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
resultNode = new FnParam {
Type = type, DefaultValue = lit, Token = token
};
return(nextLexeme);
}
resultNode = new FnParam {
Type = type, Token = token
};
return(nextLexeme);
}
public static LinkedListNode <Lexeme> TryParse(LinkedListNode <Lexeme> lexemes, out FnDecl resultNode)
{
resultNode = null;
var nextLexeme = Type.TryParse(lexemes, out Type type);
if (type == null)
{
return(lexemes);
}
if (nextLexeme.Value.Type != LT.IDENT)
{
return(lexemes);
}
Lexeme token = nextLexeme.Value;
nextLexeme = nextLexeme.Next;
if (nextLexeme.Value.Type != LT.OP_PAREN_O)
{
return(lexemes);
}
nextLexeme = nextLexeme.Next;
List <FnParam> fnParams = new List <FnParam>();
nextLexeme = FnParam.TryParse(nextLexeme, out FnParam arg);
if (arg != null)
{
fnParams.Add(arg);
while (nextLexeme.Value.Type == LT.OP_COMMA)
{
nextLexeme = nextLexeme.Next;
nextLexeme = FnParam.TryParse(nextLexeme, out arg);
if (arg == null)
{
throw new Exception($"Trailing comma in argument list at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
fnParams.Add(arg);
}
}
if (nextLexeme.Value.Type != LT.OP_PAREN_C)
{
throw new Exception($"Missing closing parenthesis in function definition at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
nextLexeme = nextLexeme.Next;
if (nextLexeme.Value.Type != LT.OP_BRACE_O)
{
throw new Exception($"Cannot find function body opening brace at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
nextLexeme = nextLexeme.Next;
List <Stmt> stmts = new List <Stmt>();
nextLexeme = Stmt.TryParse(nextLexeme, out Stmt stmt);
while (stmt != null)
{
stmts.Add(stmt);
nextLexeme = Stmt.TryParse(nextLexeme, out stmt);
}
if (nextLexeme.Value.Type != LT.OP_BRACE_C)
{
throw new Exception($"Missing closing brace for function body at {nextLexeme.Value.File}:{nextLexeme.Value.Line}");
}
nextLexeme = nextLexeme.Next;
resultNode = new FnDecl {
Type = type, Parameters = fnParams, Body = new BlockBody(stmts), Token = token
};
return(nextLexeme);
}