public override Maybe<Result> VisitTerm_expr(QueryParser.Term_exprContext context)
{
if (context.string_const() != null)
return new ResultSingle(new ValueString(context.string_const().GetText().Trim('\"'))).Just()
.FMap(Result.Id);
if (context.bool_const() != null)
return new ResultSingle(new ValueBoolean(context.bool_const().TRUE() != null)).Just()
.FMap(Result.Id);
if (context.int_const() != null)
return new ResultSingle(new ValueInt(int.Parse(context.int_const().GetText()))).Just()
.FMap(Result.Id);
if (context.double_const() != null)
return new ResultSingle(new ValueDouble(double.Parse(context.double_const().GetText(),
CultureInfo.InvariantCulture))).Just().FMap(Result.Id);
if (context.LBRACE() != null)
//return new ResultSingle(new ValueSet());
throw new NotImplementedException("term_expr: {}");
if (context.LBRACK() != null)
throw new NotImplementedException("term_expr: []");
if (context.LT() != null)
throw new NotImplementedException("term_expr: <...>");
if (context.cond_expr() != null)
return new CondExprVisitor(_zmi, _env).Visit(context.cond_expr());
if (context.statement() != null)
return VisitStmt(context.statement()).FMap(Result.Id);
var id = context.identifier().ID().GetText();
if (context.LPAREN() != null)
return VisitFunction(id, context);
var cell = _env.GetIdent(id, out var hasColumn);
return !hasColumn ? Maybe<Result>.Nothing : cell.Just();
}
private Maybe<Result> VisitFunction(string id, QueryParser.Term_exprContext context)
{
List<Result> arguments;
if (context.MUL() != null)
arguments = _env.ToList();
else
{
var searchedFor = context.expr_list()?.cond_expr()
.Select(c => new CondExprVisitor(_zmi, _env).Visit(c))
.Sequence();
if (searchedFor == null)
arguments = new List<Result>();
else if (searchedFor.HasNothing)
return Maybe<Result>.Nothing;
else
arguments = searchedFor.Val;
}
return Functions.Instance.Evaluate(id, arguments);
}
/// <summary>
/// Visit a parse tree produced by <see cref="QueryParser.term_expr"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public virtual Result VisitTerm_expr([NotNull] QueryParser.Term_exprContext context)
{
return(VisitChildren(context));
}
