// The guts of the REPL. It extendsthe C#-Mal reference REPL
// to handle (1) multi-line forms and (2) multi-form lines.
public void RunREPL()
{
while (true)
{
try
{
// Read standard input.
string line = ReadLine.Readline("JKL> ");
// Exit if EOF or ctrl-Z.
if (line == null)
{
break;
}
// Go round again if empty line (user hit return).
if (line == "")
{
continue;
}
// Tokenise the input and load the tokens into a Reader object.
MalReader.Reader rdr = new MalReader.Reader(MalReader.Tokenizer(line));
// Loop until all tokens on the line have been consumed. This handles lines
// like (a b) (c d) - where Mal REPL would silently ignore (c d)
while (rdr.Peek() != null)
{
// Parse input to create a Mal abstract syntax tree. The parser
// attempts to reload the reader if it runs out of tokens mid form.
MalVal ast = READMULTILINE(rdr);
// Evaluate the ast and print the result.
Console.WriteLine(PRINT(EVAL(ast, myEnv)));
}
}
catch (MalParseError e)
{
Console.WriteLine(e.Message);
}
catch (MalEvalError e)
{
Console.WriteLine(e.Message);
}
catch (MalInternalError e)
{
Console.WriteLine(e.Message);
}
}
}
// Handle multi-lines.
static MalVal READMULTILINE(MalReader.Reader rdr)
{
return(MalReader.read_str_multiline(rdr));
}