diff options
Diffstat (limited to 'tuplr.cpp')
| -rw-r--r-- | tuplr.cpp | 49 |
1 files changed, 49 insertions, 0 deletions
@@ -28,6 +28,24 @@ using boost::format; Funcs AConsCall::funcs; +template<typename Atom> +ostream& +operator<<(ostream& out, const Exp<Atom>& exp) +{ + switch (exp.type) { + case Exp<Atom>::ATOM: + out << exp.atom; + break; + case Exp<Atom>::LIST: + out << "("; + for (size_t i = 0; i != exp.size(); ++i) + out << exp.at(i) << ((i != exp.size() - 1) ? " " : ""); + out << ")"; + break; + } + return out; +} + /*************************************************************************** * Lexer * ***************************************************************************/ @@ -103,6 +121,34 @@ readExpression(Cursor& cur, istream& in) /*************************************************************************** + * Macro Functions * + ***************************************************************************/ + +inline SExp +macDef(PEnv& penv, const SExp& exp) +{ + if (exp.size() != 3) throw Error("`def' requires exactly 2 arguments", exp.loc); + if (exp.at(1).type == SExp::ATOM) { + return exp; + } else { + // (def (f x) y) => (def f (fn (x) y)) + SExp argsExp(exp.loc); + for (size_t i = 1; i < exp.at(1).size(); ++i) + argsExp.push_back(exp.at(1).at(i)); + SExp fnExp(exp.at(2).loc); + fnExp.push_back(SExp(exp.at(2).loc, "fn")); + fnExp.push_back(argsExp); + fnExp.push_back(exp.at(2)); + SExp ret(exp.loc); + ret.push_back(exp.at(0)); + ret.push_back(exp.at(1).at(0)); + ret.push_back(fnExp); + return ret; + } +} + + +/*************************************************************************** * Parser Functions * ***************************************************************************/ @@ -153,6 +199,9 @@ initLang(PEnv& penv, TEnv& tenv) penv.reg(false, "#t", PEnv::Handler(parseLiteral<bool>, &trueVal)); penv.reg(false, "#f", PEnv::Handler(parseLiteral<bool>, &falseVal)); + // Macros + penv.defmac("def", macDef); + // Special forms penv.reg(true, "fn", PEnv::Handler(parseFn)); penv.reg(true, "if", PEnv::Handler(parseCall<AIf>)); |