diff options
| -rw-r--r-- | prelude.cpp | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/prelude.cpp b/prelude.cpp index 7d9b4c3..f9cf6ff 100644 --- a/prelude.cpp +++ b/prelude.cpp @@ -18,7 +18,6 @@ const AST afterBootstrap=AST(R"RAW( (def 'const \x \y x) (def 'print (. putstr repr)) (def '$ \f \x (f x)) - (def 'if \c \t \f (__if c (() t) (() f))) (def 'last \l (if (nil (tail l)) (head l) (last (tail l)))) (def 'init \l (if (nil (tail l)) '() (cons (head l) (init (tail l)))))) )RAW"); @@ -31,6 +30,11 @@ static AST dofunction(const AST&){ return doNative; } + +const AST chooseFirstLambda=AST::makeLambda("",AST::makeLambda("",AST::makeIndex(2))); +const AST chooseSecondLambda=AST::makeLambda("",AST::makeLambda("",AST::makeIndex(1))); + + class PreludeInit{ public: PreludeInit(Environment &intoEnv){ @@ -99,17 +103,13 @@ public: return AST::makeNumber(arg.numval==0); })); - intoEnv.define("__if",checkedHook("__if",{AST::Type::number},{AST::Type::tuple},{AST::Type::tuple}, - [](Environment&,const AST &arg1,const AST &arg2,const AST &arg3) -> AST { - if(arg2.terms.size()!=2||arg3.terms.size()!=2){ - throw FormError("Then and else arguments to '__if' should be 2-tuples with value in second element"); - } - const AST &choice=arg1.numval!=0?arg2:arg3; - AST res=choice.terms[1]; - if(choice.quoted){ - res.quoted=true; + intoEnv.define("if",checkedHook("if",{AST::Type::number}, + [](Environment&,const AST &arg) -> AST { + if(arg.numval!=0){ + return chooseFirstLambda; + } else { + return chooseSecondLambda; } - return res; })); intoEnv.define("+",checkedHook("+",{AST::Type::number,AST::Type::string}, |