/// <summary>
/// REPL-execute a given line in an interpreter,
/// indicating whether it was incomplete, and
/// restoring the interpreter afterwards.
/// </summary>
/// <param name="interp">
/// Interpreter to use
/// </param>
/// <param name="obj">
/// Module object where method declarations will be added.
/// </param>
/// <param name="memo">
/// Restoration point for the interpreter context.
/// </param>
/// <param name="line">
/// Line of code to execute.
/// </param>
/// <param name="unfinished">
/// Set to true if this line was incomplete and could not
/// be executed for that reason.
/// </param>
/// <param name="result">
/// Result of the executed expression.
/// </param>
public static int RunLine(Interpreter interp,
UserObject obj,
Interpreter.ScopeMemo memo,
string line,
out bool unfinished, out GraceObject result)
{
result = null;
ParseNode module;
ObjectConstructorNode mod = null;
var isExtensionTrait = false;
try {
var p = new Parser("source code", line);
module = p.Parse();
var opm = (ObjectParseNode)module;
if (opm.Body.Count == 1)
{
// Tricky hack to let extensions be defined interactively.
var trait = opm.Body[0] as TraitDeclarationParseNode;
isExtensionTrait = (trait != null &&
trait.Signature.Name.EndsWith("Extension"));
}
var trans = new ExecutionTreeTranslator();
mod = (ObjectConstructorNode)trans.Translate(opm);
}
catch (StaticErrorException ex)
{
if (ex.Code == "P1001")
{
// "Unexpected end of file" is expected in the
// repl for unfinished statements.
unfinished = true;
return(1);
}
else
{
// All other errors are errors.
unfinished = false;
return(1);
}
}
unfinished = false;
if (mod != null)
{
try
{
// The "module" object can only really have
// a single element, but we don't know whether
// it's a method, statement, or expression yet.
foreach (var meth in mod.Methods.Values)
{
obj.AddMethod(meth.Name,
new Method(meth, memo));
}
foreach (var node in mod.Body)
{
var inherits = node as InheritsNode;
if (inherits != null)
{
var ms = inherits.Inherit(interp, obj);
obj.AddMethods(ms);
obj.RunInitialisers(interp);
}
var v = node as VarDeclarationNode;
var d = node as DefDeclarationNode;
Cell cell;
var meths = new Dictionary <string, Method>();
if (v != null)
{
obj.CreateVar(v.Name, meths,
v.Readable, v.Writable, out cell);
obj.AddMethods(meths);
if (v.Value != null)
{
cell.Value = v.Value.Evaluate(interp);
}
result = GraceObject.Done;
continue;
}
if (d != null)
{
obj.CreateDef(d.Name, meths,
d.Public, out cell);
obj.AddMethods(meths);
cell.Value = d.Value.Evaluate(interp);
result = GraceObject.Done;
continue;
}
var ret = node.Evaluate(interp);
if (ret != null &&
ret != GraceObject.Done &&
ret != GraceObject.Uninitialised)
{
interp.Print(interp, ret);
}
result = ret;
}
if (isExtensionTrait)
{
interp.LoadExtensionsFromObject(obj);
}
}
catch (GraceExceptionPacketException e)
{
ErrorReporting.WriteLine("Uncaught exception:");
ErrorReporting.WriteException(e.ExceptionPacket);
if (e.ExceptionPacket.StackTrace != null)
{
foreach (var l in e.ExceptionPacket.StackTrace)
{
ErrorReporting.WriteLine(" from "
+ l);
}
}
return(1);
}
finally
{
// No matter what happened, restore the interpreter
// to as pristine a state as we can manage before
// the next time.
interp.RestoreExactly(memo);
interp.PopCallStackTo(0);
mod = null;
}
}
return(0);
}