public void Build(TokenList tokens)
{
// read "set varname to"
tokens.Advance();
varNameToken = tokens.Current;
tokens.Advance();
Token toToken = tokens.Current;
tokens.Advance();
// make sure the variable name token is a valid word/name for a variable
if (varNameToken.TokenType != TokenType.Word)
{
throw new TokenParserException("The \"set\" instruction must be followed by a word of your choice that will be subsequently used to hold some value.", tokens.Previous);
}
if (TokenParser.IsReservedWord(varNameToken.Value))
{
throw new TokenParserException("You can't use \"" + varNameToken.Value + "\" as a variable name. It is the keyword for either an expression or an instruction.", varNameToken);
}
// make sure the "to" token is actually the word "to"
if (toToken.TokenType != TokenType.Word || toToken.Value != "to")
{
throw new TokenParserException("The \"set\" instruction must be formatted like this: \"set something to some_expression\"", toToken);
}
// build the expression that will be evaluated and assigned to the variable at run time
expr = TokenParser.BuildExpression(tokens);
}
public void Build(TokenList tokens)
{
// store the "list each [variable] in [list_expression]" tokens
token = tokens.Current;
Token eachToken = tokens.Peek(1);
iteratorToken = tokens.Peek(2);
Token inToken = tokens.Peek(3);
listToken = tokens.Peek(4); // the first token of the list expression
tokens.Advance(4);
// make sure the "each" token is actually the word "each"
if (eachToken.Value != "each" || eachToken.TokenType != TokenType.Word)
{
throw new TokenParserException("\"list\" must be followed by the word \"each\".", eachToken);
}
// validate the various tokens
if (iteratorToken.TokenType != TokenType.Word)
{
throw new TokenParserException("You must specify a word here that can be used as a variable, e.g. \"list each item in whatever\"", iteratorToken);
}
if (TokenParser.IsReservedWord(iteratorToken.Value))
{
throw new TokenParserException("You can't use \"" + iteratorToken.Value + "\" as a variable name. It is the keyword for either an expression or an instruction.", iteratorToken);
}
if (inToken.Value != "in" || inToken.TokenType != TokenType.Word)
{
throw new TokenParserException("\"list each [something] must be followed by the word \"in\".", inToken);
}
// build the list expression and the subsequent instruction list to loop through
expr = TokenParser.BuildExpression(tokens);
instructions = new InstructionList();
instructions.IsLoopBlock = true;
instructions.Build(tokens);
}