unmake Y a primitive

it only saves compile time, not runtime
removed the warning about it as well

Author: Johan Wiltink

src/lambda-calculus.js

@@ -96,7 +96,8 @@ function Primitive(v) { return new Tuple(new V( "<primitive>" ), new Env([[ "<pr
 
 const primitives = new Env;
 primitives.setThunk( "trace", new Tuple( Primitive( function(v) { console.info(String(v.term)); return v; } ), new Env ) );
-primitives.setThunk( "Y", new Tuple( new L("f",new A(new L("x",new A(new V("f"),new A(new V("x"),new V("x")))),new L("x",new A(new V("f"),new A(new V("x"),new V("x")))))), new Env ) );
+
+const Y = new L("f",new A(new L("x",new A(new V("f"),new A(new V("x"),new V("x")))),new L("x",new A(new V("f"),new A(new V("x"),new V("x"))))));
 
 function fromInt(n) { return fromIntWith()(n); }
 
@@ -195,7 +196,7 @@ function parseWith(cfg={}) {
               if ( verbosity >= "Concise" ) console.error(`parse: while defining ${ name } = ${ term }`);
               throw new ReferenceError(`undefined free variable ${ nm }`);
             }
-          } , new Tuple( FV.has(name) ? new A(env.getValue("Y"),new L(name,term)) : term , new Env ) );
+          } , new Tuple( FV.has(name) ? new A(Y,new L(name,term)) : term , new Env ) );
         else if ( purity==="PureLC" )
           if ( FV.size ) {
             if ( verbosity >= "Concise" ) console.error(`parse: while defining ${ name } = ${ term }`);
@@ -301,8 +302,6 @@ function parseWith(cfg={}) {
       const [i,r] = defn(0);
       if ( i===code.length ) {
         const [name,term] = r;
-        if ( name == "Y" )
-          console.warn("<span style=\"color:orange\">redefining Y is NOT RECOMMENDED and you do so at your peril</span>");
         if ( config.verbosity >= "Loquacious" )
           console.debug(`compiled ${ name }${ config.verbosity >= "Verbose" ? ` = ${ term }` : "" }`);
         return env.setThunk( name, wrap(name,term));

tests/basics-binary-scott/solution.txt

@@ -12,6 +12,7 @@ S  = \ f g x . f x (g x)
 T  = \ x f . f x
 V  = \ x y f . f x y
 W  = \ f x . f x x
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 Z  = \ f . ( \ x . f \ y . x x y ) ( \ x . f \ y . x x y )
 
 #import Boolean.lc

tests/basics-church/solution.txt

@@ -12,6 +12,7 @@ S  = \ f g x . f x (g x)
 T  = \ x f . f x
 V  = \ x y f . f x y
 W  = \ f x . f x x
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 Z  = \ f . ( \ x . f \ y . x x y ) ( \ x . f \ y . x x y )
 
 #import ChurchBoolean.lc

tests/is-prime-scott/solution.txt

@@ -3,6 +3,7 @@
 B = \ f g x . f (g x)
 I = \ x . x
 K = \ x _ . x
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 True = \ t f . t
 False = \ t f . f
 Succ = \ n z s . s n

tests/is-prime/solution.txt

@@ -1,5 +1,6 @@
 # JohanWiltink
 
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 True = \ t f . t
 False = \ t f . f
 Succ = \ n s z . s (n s z)

tests/prime-sieve/solution.txt

@@ -15,6 +15,7 @@ S  = \ f g x . f x (g x)
 T  = \ x f . f x
 V  = \ x y f . f x y
 W  = \ f x . f x x
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 Z  = \ f . ( \ x . f \ y . x x y ) ( \ x . f \ y . x x y )
 
 #import Ordering.lc

tests/scott-lists/solution.txt

@@ -14,6 +14,7 @@ S = \ f g x . f x (g x)
 T = \ x fn . fn x
 V = \ x y fn . fn x y
 W = \ f x . f x x
+Y = \ f . ( \ x . f (x x) ) ( \ x . f (x x) )
 #import scott-booleans.ls
 False = K
 True  = KI