Make 1998/fanf more like the original
I've added some notes to `thanks-for-help` explaining the changes, and removed the caveat from the README since the code is now much closer to the original. Fun fact: T for Tony is once again the only letter not used in fanf.c
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Tony Finch committed
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@@ -41,7 +41,7 @@ include ../../var.mk
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CSILENCE= -Wno-pointer-bool-conversion -Wno-unused-parameter -Wno-main \
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-Wno-implicit-function-declaration -Wno-address \
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-Wno-builtin-declaration-mismatch -Wno-int-conversion \
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-Wno-gnu-line-marker
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-Wno-gnu-line-marker -Wno-strict-prototypes
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# Attempt to silence unknown warning option
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#
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@@ -132,8 +132,8 @@ all: data ${TARGET}
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${PROG}: ${PROG}.c
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@echo "This may take some time to complete:"
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${CC} ${PROG}.c -E > ${PROG}tmp1.c
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${CC} ${PROG}tmp1.c -E > ${PROG}tmp2.c
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${CC} ${CSTD} ${PROG}.c -E > ${PROG}tmp1.c
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${CC} ${CSTD} ${PROG}tmp1.c -E > ${PROG}tmp2.c
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${CC} ${CFLAGS} ${PROG}tmp2.c ${LDFLAGS} -o $@
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# alternative executable
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@@ -26,14 +26,6 @@ Enter an expression on standard input. To try some we have selected:
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## Judges' remarks:
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### Historical aside:
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At a time the code in [fanf.c](%%REPO_URL%%/1998/fanf/fanf.c) was that of [fanf.orig.c](%%REPO_URL%%/1998/fanf/fanf.orig.c)
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but to get this to compile in modern systems it had to be translated to what you
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now see. The intermediate steps can still be performed but they might be
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different from the past. This should be kept in mind as you read the below
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remarks.
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This program translates lambda expressions into combinator
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expressions. But you do not need to know Lambda Calculus to be
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impressed by this program!
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+84
-79
@@ -1,40 +1,45 @@
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#define Xinclude #include
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Xinclude <stdlib.h>
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Xinclude <stdio.h>
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#define i int
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#define n struct n
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#define T , char **C) { return (
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#define x ){ return (
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#define A ->
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#define N n*
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#define l #define
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#define p(p) l p b ( m p u X )
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l i int
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l n struct n
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l x ){ return (
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l A ->
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l N n*
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n { i c ; N L ; N R ; N U ; N ( * F ) ( N ) ; } ;
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#define F A F
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#define U A U
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#define R A R
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#define L A L
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#define m q = malloc(sizeof * q ) Z F =
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#define e z F ( p ) ) ; }
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#define f e N
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#define g z L Q s f
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#define h ( N p x
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#define H h p L U Q
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#define s R z R = q
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#define t ) ? p : (
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#define z , p
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#define Z , q
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#define Q = p
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#define w ! p U t p U L Q z Q U ,
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#define D W p R U = 0 z R Q R F ( p R ) z R F != E t
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#define W h w
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#define X z = q , 0
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#define V w p F = v z L Q
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#define O m o Z L Q
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#define M m E Z A c =
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#define r Z R Q
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#define u Z U Q
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#define a ) ) ) ? 0 : j ( !
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#define k ( i c x
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#define y 0 ) ; } i
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l F A F
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l U A U
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l R A R
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l L A L
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l m q = malloc(sizeof * q ) Z F =
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l e z F ( p ) ) ; }
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l f e N
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l g z L Q s f
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l h ( N p x
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l H h p L U Q
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l s R z R = q
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l t ) ? p : (
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l z , p
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l Z , q
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l Q = p
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l w ! p U t p U L Q z Q U ,
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l D W p R U = 0 z R Q R F ( p R ) z R F != E t
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l W h w
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l X z = q , 0
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l V w p F = v z L Q
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l O m o Z L Q
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l M m E Z A c =
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l r Z R Q
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l u Z U Q
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l a ) ) ) ? 0 : j ( !
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l k ( i c x
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l y 0 ) ; } i
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N q ; N
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o H z Q L f
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@@ -42,9 +47,9 @@ v H U z Q L f
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K W V L R f
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J W V R f
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I h V R f
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#if 0
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Y W q Q g
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#endif
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S W w w O L L R r s , O L R r R R g
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E D p F Q L A c - p R A c ? J : K f
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P D w putchar ( p L R A c ) , m I g
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@@ -53,64 +58,64 @@ p ;
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i j k c ? O U r u U U X : y b k y d k y
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#define d(d) ( ( d a b
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#define b(b) ( ( b a d
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#define E(E) b ( M E u X )
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l d(d) ( ( d a b
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l b(b) ( ( b a d
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l E(E) b ( M E u X )
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main ( i c T
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main ( x i ) ! (
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#define I b ( m I u X )
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#define J b ( m J u X )
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#define K b ( m K u X )
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p (I)
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p (J)
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p (K)
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#if 0
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p (Y)
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#endif
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p (P)
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p (G)
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p (S)
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l B b (S (K S) K)
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l SS b (B (B S) B)
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l C b (SS B S (K K))
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l CC b (B (B C) B)
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l BB b (CC B (B B B) B)
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l Y b (S (C B (S I I)) (C B (S I I)))
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#define P b ( m P u X )
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#define G b ( m G u X )
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l CI b (C I)
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#define S b ( m S u X )
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#define B b (S (K S) K)
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#define SS b (B (B S) B)
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#define C b (SS B S (K K))
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#define CC b (B (B C) B)
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#define BB b (CC B (B B B) B)
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l ef E(EOF)
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l sp E(' ')
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l ob E('(')
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l cb E(')')
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l lm E('\\')
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l nl E('\n')
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l ht E('\t')
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l qs E('S')
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l qk E('K')
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l qi E('I')
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#define Y b (S (C B (S I I)) (C B (S I I)))
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l pair b (BB (B (B K)) C CI)
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l atom b (B K CI)
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#define CI b (C I)
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l bind b (CC B B C)
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#define ef E((-1))
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#define sp E(' ')
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#define ob E('(')
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#define cb E(')')
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#define lm E('\\')
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#define nl E('\n')
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#define ht E('\t')
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#define qs E('S')
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#define qk E('K')
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#define qi E('I')
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l ore b (SS (CI K))
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l gns b (Y (B (bind G) (CC S (C (ore sp (ore nl ht))) CI)))
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#define pair b (BB (B (B K)) C CI)
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#define atom b (B K CI)
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l pr b (Y (CC C (BB CI (B (BB (bind (P ob)) K)) (SS C (CC C (BB BB bind) K) (C (CC bind) (K (P cb))))) P))
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#define bind b (CC B B C)
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l trans b (Y (B (bind gns) (S (BB S (C lm) lam) (C (BB S (C ob) brac) (S (C cb (CI (atom sp))) (S (C ef (CI (atom sp))) (B CI atom)))))))
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#define ore b (SS (CI K))
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#define gns b (Y (B (bind G) (CC S (C (ore sp (ore nl ht))) CI)))
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l brac b (S bind (B Y (C (BB B B bind) (S (BB S (BB S (S I)) (CC (BB (B K)) (BB K) pair)) (CC S (CC BB (BB C (C (CI sp)) CI)) pair)))))
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l lam b (B (bind gns) (C (CC BB bind (B CI)) abs))
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#define pr b (Y (CC C (BB CI (B (BB (bind (P ob)) K)) (SS C (CC C (BB BB bind) K) (C (CC bind) (K (P cb))))) P))
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l abs b (Y (C (BB S (BB C CI) (SS S (BB C (BB B opt)) I)) (CC S (C C (atom qi)) (B (pair (atom qk)) atom))))
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#define trans b (Y (B (bind gns) (S (BB S (C lm) lam) (C (BB S (C ob) brac) (S (C cb (CI (atom sp))) (S (C ef (CI (atom sp))) (B CI atom)))))))
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l make b (B pair (pair (atom qs)))
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#define brac b (S bind (B Y (C (BB B B bind) (S (BB S (BB S (S I)) (CC (BB (B K)) (BB K) pair)) (CC S (CC BB (BB C (C (CI sp)) CI)) pair)))))
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#define lam b (B (bind gns) (C (CC BB bind (B CI)) abs))
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#define abs b (Y (C (BB S (BB C CI) (SS S (BB C (BB B opt)) I)) (CC S (C C (atom qi)) (B (pair (atom qk)) atom))))
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#define make b (B pair (pair (atom qs)))
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#define opt b (S (S I (S (BB (CC B) CI (BB K K make)) (S (BB C (BB C (C (CI qk))) (SS (SS S) (S (BB (BB (S I)) S (BB (BB (CC B) CI) (BB K K) make)) (B (CC B (BB (CC C) (BB (C (CI qk)) (pair (atom qk))) pair)) make)) (B (C (BB B C (C (CI qi)))) make))) make))) (B K make))
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l opt b (S (S I (S (BB (CC B) CI (BB K K make)) (S (BB C (BB C (C (CI qk))) (SS (SS S) (S (BB (BB (S I)) S (BB (BB (CC B) CI) (BB K K) make)) (B (CC B (BB (CC C) (BB (C (CI qk)) (pair (atom qk))) pair)) make)) (B (C (BB B C (C (CI qi)))) make))) make))) (B K make))
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(bind (bind trans pr) (P nl) I)
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+23
-12
@@ -3257,20 +3257,31 @@ Jump to: [top](#)
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### Winning entry source code: [fanf.c](%%REPO_URL%%/1998/fanf/fanf.c)
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</div>
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[Cody](#cody) fixed this to compile. The problem was the intermediate steps to get to the
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final code that is compiled. The code is now what it essentially becomes when
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processed completely. The intermediate steps can now be performed to see how it
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expands but it can still compile and be used.
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[Cody](#cody) fixed this to compile. Tony Finch fixed it again to be
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more like the original submission. The double preprocessing is a joke
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about C and a joke about OFL so the program is less funny without it.
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Cody also added a second arg to `main()` out of an abundance of caution as some
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versions of `clang` complain about the number of args to `main()`. These versions
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claim that only 0, 2 or 3 are allowed but it does allow 1 anyway. It is quite
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possible though that this will change so it is fixed in case this happens. As it
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is mostly just through the C pre-processor Cody added a new macro to make the
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code look like the original with just an extra arg. See the
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FAQ on "[main function args](faq.html#arg_count)"
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for more details.
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There were a couple of problems with the double preprocessing that
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upset modern compilers:
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* Recent versions of `gcc` wrap `#line` marks around the expansion
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of `EOF` which broke up `#define ef E(EOF)` across multiple lines.
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This can be avoided by processing `#include` in the second
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preprocessor phase.
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(Tony vaguely remembers some indecision about when to `#include`,
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in particular whether preprocessing the headers twice would lead
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to trouble. Early `#include` seemed to work and was shorter so
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that was what the original submission did.)
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* System headers can be sensitive to compiler options, for example
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`restrict` keywords might be omitted when compiling with
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`-std=gnu90`. Consistency options need to be used at all stages.
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Cody also added a second arg to `main()`. Tony removed both args since
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neither of them are used and it's shorter that way (though it provokes
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a warning about a non-prototype function definition). See the FAQ on
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"[main function args](faq.html#arg_count)" for more details.
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In some versions of `clang` `-Wno-int-conversion` had to be added to the
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`CSILENCE` variable of the Makefile.
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