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Processor.cs
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Processor.cs
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using System;
using System.Collections.Generic;
using System.Linq;
namespace Scallop
{
class Processor
{
Environment _env;
Lexer _lexer;
Parser _parser;
const string _PROMPT = "scallop> ";
public Processor()
{
_env = Environment.MakeInitialEnvironment();
_lexer = new Lexer(ch => ch == ' ' || ch == '\t');
_parser = new Parser();
}
public void RunREPL(Func<string> read, Action<string> write)
{
while (true)
{
string line = Prompt(read, write, _PROMPT);
IEnumerable<SExp> exps = null;
try
{
exps = _parser.Parse(_lexer.EnumerateTokens(line));
}
catch (LexerException e)
{
write(e.Message + "\n");
continue;
}
catch (ParserException e)
{
write(e.Message + "\n");
continue;
}
SExp result = null;
try { result = Utilities.Eval(exps.ToArray(), _env); }
catch (ApplicationTerminationException e)
{
write(e.Message + "\n");
break;
}
catch (Exception e)
{
write(e.Message + "\n");
continue;
}
catch (System.Exception e)
{
write(e.Message + "\n");
continue;
}
write(result + "\n");
}
}
public static string Prompt(Func<string> read, Action<string> write, string msg)
{
write(msg);
return read();
}
}
}