static public (Statement, string) parseStatement(ref lexer.Lexer Lexer)
{
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
switch (Lexer.LookAhead())
{
case lexer.TOKEN_PRINT:
return(parsePrint(ref Lexer));
case lexer.TOKEN_VAR_PREFIX:
return(parseAssignment(ref Lexer));
default:
return(null, "parseStatement(): unknown Statement.");
}
}
//Statement ::= Print | Assignment
static public (List <Statement>, string) parseStatements(ref lexer.Lexer Lexer)
{
List <Statement> statements = new List <Statement>();
while (!isSourceCodeEnd(Lexer.LookAhead()))
{
var(statement, error) = parseStatement(ref Lexer);
if (error != null)
{
return(null, error);
}
statements.Add(statement);
}
return(statements, null);
}
//String ::= '"' '"' Ignored | '"' StringCharacter '"' Ignored
static public (string, string) parseString(ref lexer.Lexer Lexer)
{
string str = "";
switch (Lexer.LookAhead())
{
case lexer.TOKEN_DUOQUOTE:
Lexer.NextTokenIs(lexer.TOKEN_DUOQUOTE);
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
return(str, null);
case lexer.TOKEN_QUOTE:
Lexer.NextTokenIs(lexer.TOKEN_QUOTE);
str = Lexer.scanBeforeToken(lexer.tokenNameMap[lexer.TOKEN_QUOTE]);
Lexer.NextTokenIs(lexer.TOKEN_QUOTE);
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
return(str, null);
default:
return(null, "parseString(): not a string.");
}
}