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);
}
public void Build(TokenList tokens)
{
//store the "while" token
token = tokens.Current;
tokens.Advance();
// build the expression to evaluate for each iteration through the loop
expr = TokenParser.BuildExpression(tokens);
// build the list of instructions to execute inside the loop
list = new InstructionList();
list.IsLoopBlock = true;
list.Build(tokens);
}
public void Build(TokenList tokens)
{
instructionToken = tokens.Current;
Token token = instructionToken;
// advance past the instruction token/symbol
tokens.Advance();
// build condition expression
IExpression expr = TokenParser.BuildExpression(tokens);
// build the instruction list that will execute if the expression evaluates to true
InstructionList list = new InstructionList();
list.AcceptELSEInPlaceOfEND = true;
list.Build(tokens);
executionPaths.Add(new ExecutionPath(expr, list, token));
// if any elseif statements were used, build the execution paths for each one
while (list.Terminator == InstructionList.TerminatorType.ElseIf)
{
token = tokens.Previous;
expr = TokenParser.BuildExpression(tokens);
list = new InstructionList();
list.AcceptELSEInPlaceOfEND = true;
list.Build(tokens);
executionPaths.Add(new ExecutionPath(expr, list, token));
}
// if an else statement was used, build the instruction list that will execute if the expression evaluates to false
if (list.Terminator == InstructionList.TerminatorType.Else)
{
token = tokens.Previous;
list = new InstructionList();
list.AcceptELSEInPlaceOfEND = true;
list.Build(tokens);
executionPaths.Add(new ExecutionPath(null, list, token));
}
}
public ExecutionPath(IExpression condition, InstructionList instructions, Token token)
{
Condition = condition;
Instructions = instructions;
Token = token;
}
public ExecutionPath(IExpression condition, InstructionList instructions, Token token)
{
Condition = condition;
Instructions = instructions;
Token = token;
}