diff options
Diffstat (limited to 'prelude.cpp')
| -rw-r--r-- | prelude.cpp | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/prelude.cpp b/prelude.cpp index 5738844..8fc9d8a 100644 --- a/prelude.cpp +++ b/prelude.cpp @@ -17,7 +17,9 @@ const AST afterBootstrap=AST(R"RAW( (def 'id \x x) (def 'const \x \y x) (def 'print (. putstr repr)) - (def '$ \f \x (f x))) + (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))))) )RAW"); static AST dofunction(const AST&); @@ -60,7 +62,11 @@ public: if(arg.terms.size()==0){ throw FormError("Empty tuple in 'head'"); } - return arg.terms[0]; + AST res=arg.terms[0]; + if(arg.quoted){ + res.quoted=true; + } + return res; })); intoEnv.define("tail",checkedHook("tail",{AST::Type::tuple}, @@ -68,7 +74,11 @@ public: if(arg.terms.size()==0){ throw FormError("Empty tuple in 'tail'"); } - return AST::makeTuple(Terms(arg.terms.begin()+1,arg.terms.end())); + AST res=AST::makeTuple(Terms(arg.terms.begin()+1,arg.terms.end())); + if(arg.quoted){ + res.quoted=true; + } + return res; })); intoEnv.define("nil",checkedHook("nil",{AST::Type::tuple}, @@ -81,13 +91,17 @@ public: return AST::makeNumber(arg.numval==0); })); - intoEnv.define("if",checkedHook("if",{AST::Type::number},{},{}, + 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(arg1.numval!=0){ - return arg2; - } else { - return arg3; + 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; } + return res; })); intoEnv.define("+",checkedHook("+",{AST::Type::number,AST::Type::string}, |