// Assignment:: VAR? ident := value
// If ident does not exist, creates a typed catalog entry (using return type if Funval)
// Sets initial value, or updates but only if was VAR and same type
public AstStatement Assignment(string ident, AstValue value, string varopt)
{
if (Symbols.CanDefGlobal(ident))
{
if (value is AstFunval)
{
var cvalue = (value as AstFunval).Value;
Symbols.AddDeffun(ident, cvalue.DataType, cvalue.Lookup.Columns, cvalue.Accums, varopt != null);
}
else
{
Symbols.AddVariable(ident, value.DataType, SymKinds.CATVAR, varopt != null);
}
Symbols.AddCatalog(Symbols.FindIdent(ident));
}
else
{
var sym = FindCatVar(ident);
if (sym == null || sym.IsCallable || !sym.Mutable)
{
Parser.ParseError("cannot assign to '{0}'", sym.Name);
}
if (sym.DataType != value.DataType)
{
Parser.ParseError("type mismatch: '{0}'", sym.Name);
}
}
return(GenFunCall(FindFunc(SymNames.Assign), Args(Text(ident), value)));
}
// name, type and source of a single VAR declaration, can be
// a) VAR ident : type
// b) VAR ident [: typewithheading] (source)
public AstStatement VarDecl(string ident, AstType type, AstLiteral source)
{
var what = ident; // reserved for future use
var isimport = (source != null);
var datatype = (type == null) ? null
: isimport?Types.Relof(type.DataType)
: type.DataType;
if (isimport && datatype == null)
{
if (type != null)
{
Parser.ParseError($"type with heading required for '{ident}'");
}
datatype = Cat.GetRelvarType(source.Value.ToString(), what); // peek the file
if (datatype == null)
{
Parser.ParseError("cannot find '{0}' as '{1}'", ident, source);
}
}
Symbols.AddVariable(ident, datatype, SymKinds.CATVAR, true);
Symbols.AddCatalog(Symbols.FindIdent(ident));
return((isimport) ? GenFunCall(FindFunc(SymNames.Import), Args(source, Text(ident), Text(what), Text(Parser.Cat.SourcePath)))
: GenFunCall(FindFunc(SymNames.Assign), Args(Text(ident), LitValue(datatype.DefaultValue()))));
}
public AstTypedef UserType(string ident, AstField[] fields)
{
var ff = fields.Select(a => DataColumn.Create(a.Name, a.DataType)).ToArray();
var ut = DataTypeUser.Get(ident, ff);
Symbols.AddUserType(ident, ut);
Symbols.AddCatalog(Symbols.FindIdent(ident));
return(new AstUserType {
DataType = DataTypes.Void
});
}
// finalise function definition, from basic definition previously created
// set or check return type
// null body just defines type
// Note: null arguments means argless (lazy) rather than deffun
// BUG: a persistent function must not reference a non-persistent global
public AstStatement Deffun(string ident, AstType rettype, IList <AstField> arguments, AstBodyStatement body)
{
var op = FindDefFunc(ident);
var callinfo = op.CallInfo;
if (callinfo.ReturnType == DataTypes.Unknown)
{
callinfo.ReturnType = body.DataType;
}
else if (callinfo.ReturnType != body.DataType)
{
Parser.ParseError($"{ident} return type mismatch");
}
if (op.DataType == DataTypes.Unknown)
{
if (arguments == null)
{
op.DataType = callinfo.ReturnType;
}
}
else if (op.DataType != callinfo.ReturnType)
{
Parser.ParseError("body does not match declared type");
}
// assume top overload is the one being defined
//op.callinfo.ReturnType = op.DataType;
callinfo.AccumCount = body.AccumCount;
callinfo.HasWin = body.HasWin;
// symbol is foldable if all overloads are foldable
// FIX: put this test where it's used
var foldable = (callinfo.NumArgs == 2 && arguments[0].DataType == callinfo.ReturnType && arguments[1].DataType == callinfo.ReturnType) &&
(callinfo.OverLoad == null || op.IsFoldable);
if (foldable && !op.IsFoldable)
{
op.Foldable = FoldableFlags.ANY;
}
Symbols.AddCatalog(op);
// assemble node
var code = Code(body.Statement as AstValue, Headingof(arguments), callinfo.Name, true, body.AccumCount, body.HasWin);
return(GenFunCall(FindFunc(SymNames.Defer), Args(code)));
}