private void assign(Assign node)
{
scope.set((Variable)node.children[0], eval(node.children[1]));
}
private ASTNode parseStatement(SyntaxNode node)
{
if (!node.token.Equals(grammar.t["stmt"]))
{
throw new Exception("Trying to parse a non-statement " + node.token + " as a statement, line " + node.line + ":" + node.position);
}
if (node.children[0].token.Equals(grammar.t["var"]))
{
Define ret = new Define(node);
Variable newVariable = parseVariable(node.children[1], true);
TypeName type = parseType(node.children[3]);
ret.children.Add(newVariable);
ret.children.Add(type);
newVariable.type = type.type;
if (node.children[4].children.Count > 0)
{
Expression initialValue = parseExpression(node.children[4].children[1]);
if (initialValue.type != newVariable.type)
{
addError(node, "Variable " + newVariable.name + " defined with initial value of different type");
}
ret.children.Add(initialValue);
}
else
{
ret.children.Add(null);
}
return(ret);
}
if (node.children[0].token is Identifier)
{
Assign ret = new Assign(node);
Variable var = parseVariable(node.children[0], false);
if (currentConstants.Contains(var.name))
{
addError(node, "Assignment to loop variable " + var.name);
}
Expression value = parseExpression(node.children[2]);
if (var.type != value.type)
{
addError(node, "Variable " + var.name + " assigned a value of different type");
}
ret.children.Add(var);
ret.children.Add(value);
return(ret);
}
if (node.children[0].token.Equals(grammar.t["for"]))
{
For ret = new For(node);
Variable var = parseVariable(node.children[1], false);
Expression from = parseExpression(node.children[3]);
Expression to = parseExpression(node.children[5]);
if (var.type != typeof(int))
{
addError(node, "Only ints may be iterated on");
}
if (from.type != typeof(int))
{
addError(node, "Iteration start needs to be an int");
}
if (to.type != typeof(int))
{
addError(node, "Iteration end needs to be an int");
}
ret.children.Add(var);
ret.children.Add(from);
ret.children.Add(to);
currentConstants.Add(var.name);
ret.children.Add(parse(node.children[7]));
ret.children.Add(parse(node.children[9]));
currentConstants.Remove(var.name);
return(ret);
}
if (node.children[0].token.Equals(grammar.t["read"]))
{
Read ret = new Read(node);
ret.children.Add(parseVariable(node.children[1], false));
return(ret);
}
if (node.children[0].token.Equals(grammar.t["print"]))
{
Print ret = new Print(node);
ret.children.Add(parseExpression(node.children[1]));
return(ret);
}
if (node.children[0].token.Equals(grammar.t["assert"]))
{
Assertion ret = new Assertion(node);
ret.children.Add(parseExpression(node.children[2]));
return(ret);
}
throw new Exception("Un-AST-ed syntax node, token " + node.token + ", first child " + node.children[0].token + ", line " + node.line + ":" + node.position);
}