/**********************************************************************
* Functions and Subroutines
* *******************************************************************/
//-----------------------------------------------------------
public Type Visit(Function node)
{
string functionKeyword = node.AnchorToken.Lexeme;
if (!Tables.ContainsKey(functionKeyword))
{
Tables.Add(functionKeyword, new List <SymbolTable>());
}
Tables[functionKeyword].Add(new SymbolTable());
progUnit = functionKeyword;
var functionTable = Tables[progUnit].Last();
string funcName = node[1].AnchorToken.Lexeme;
functionTable[funcName] =
new SymbolEntry(typeMapper[node[0].AnchorToken.Category]);
return(Type.VOID);
}
//-----------------------------------------------------------
public Type Visit(Parameter node)
{
var paramAssgn = node[0];
var variableName = paramAssgn[0].AnchorToken.Lexeme;
var currentTable = Tables[progUnit].Last();
if (IdHasBeenFound(variableName))
{
if (!currentTable.Contains(variableName))
{
currentTable[variableName] =
new SymbolEntry(GetIdType(variableName));
}
else
{
if (currentTable[variableName].IsConstant)
{
throw new SemanticError(
"A variable can only be used in one parameter: "
+ variableName,
paramAssgn[0].AnchorToken);
}
}
currentTable[variableName].IsConstant = true;
var expectedType = currentTable[variableName].SymbolType;
var foundType = Visit((dynamic)paramAssgn[1]);
if (expectedType != foundType)
{
throw new SemanticError(
"Expecting type " + expectedType
+ " in assignment statement.",
paramAssgn[0].AnchorToken);
}
}
else
{
throw new SemanticError(
"Undeclared variable: " + variableName,
paramAssgn[0].AnchorToken);
}
return(Type.VOID);
}
//-----------------------------------------------------------
public Type Visit(Declaration node)
{
var currentTable = Tables[progUnit].Last();
foreach (var decl in node)
{
var variableName = decl.AnchorToken.Lexeme;
if (currentTable.Contains(variableName))
{
throw new SemanticError(
"Duplicated variable: " + variableName,
decl.AnchorToken);
}
else
{
currentTable[variableName] =
new SymbolEntry(typeMapper[node.AnchorToken.Category]);
if (decl.HasChildren())
{
var declArray = decl[0];
if (declArray.NodeChildrenCount() > 2)
{
throw new SemanticError(
"An array can have 2 dimensions at most: "
+ variableName,
decl.AnchorToken);
}
for (int i = 0; i < declArray.NodeChildrenCount(); i++)
{
if (Visit((dynamic)declArray[i]) != Type.INTEGER)
{
throw new SemanticError(
"Only integers can be used as Array dimensions.",
declArray[i].AnchorToken);
}
if (declArray[i].AnchorToken.Category == TokenCategory.IDENTIFIER)
{
var dimName = declArray[i].AnchorToken.Lexeme;
if (!currentTable.Contains(dimName))
{
throw new SemanticError(
"Undeclared dimension: " + dimName,
declArray[i].AnchorToken);
}
if (!currentTable[dimName].IsConstant)
{
throw new SemanticError(
"Cannot use non-constant variables as"
+ " array dimensions.",
declArray[i].AnchorToken);
}
}
currentTable[variableName].Params
.Add(declArray[i].AnchorToken.Lexeme);
}
}
}
}
return(Type.VOID);
}