Author | Brian Robert Callahan
Compile the | Zhang Jie is responsible for editing | Tu Min
To make the challenge interesting, Brian Robert Callahan, a lecturer in information technology and network science at Rensselaer Polytechnic Institute in upstate New York, decided to write a C program that didn't look like C at all. If you turn C into another language and then write programs in that language, what happens if you compile programs with the C compiler?
To be able to write the following programs, Brian Robert Callahan thought it was a glorious thing.
#include"cpaint.h" var a, b, c, h, i, l, v, x, y, q, w, p size 65535 ， packed n size 13 ꞉integer ； procedure display(r,s,c) ; begin LOOP call A(Z) ; call H(y,x) ; call B(Z) POOL ; y ꞉＝ r; x ꞉＝ s; call A(c) ; call H(y,x) ; call B(c) ; call refresh end ; procedure fill(y,x,c,a) ; begin if(y<0 or y>w-1 or x<0 or x>q-1 or c ＝ a or Z ＜＞ a)fill꞉＝ -1 ; call draw(c) ; call fill(y+1,x,c,a) ; call fill(y-1,x,c,a) ; call fill(y,x-1,c,a) ; call fill(y,x+1,c,a) end ; procedure save(r,s) ; begin i ꞉＝ 0 ; while(i<13)do begin n[i] ꞉＝ 0 ; i ꞉＝ i+1 end ; call move(w>>1,(q>>1)-6) ; call printw("Save: ") ; call echo ; call getnstr(n,12) ; call noecho ; call open(n,"w+") ; call writeChar(83) ; call writeChar(w) ; call writeChar(q) ; LOOP call writeChar(Z) POOL ; y ꞉＝ r; x ꞉＝ s; call close ; call move(y,x) end ; procedure load(packed ʌ n) ; begin call open(n,"r") ; call check ; LOOP readln(c); call draw(c) POOL ; c ꞉＝ 0; call close end ; procedure m ; begin l ꞉＝ 0 ; v ꞉＝ 1 ; call A(c) ; call H(0,0) ; call B(c) ; call refresh ; while(v)do begin read(inp) ; '/':l ꞉＝ not l ; if(l)call draw(c) ; OK 'k':y ꞉＝ y-1 ; if(y<0)y ꞉＝ 0 ; if(l)call draw(c) ; OK 'j':y ꞉＝ y+1 ; if(y>w-1)y ꞉＝ w-1 ; if(l)call draw(c) ; OK 'h':x ꞉＝ x-1 ; if(x<0)x ꞉＝ 0 ; if(l)call draw(c) ; OK 'l':x ꞉＝ x+1 ; if(x>q-1)x ꞉＝ q-1 ; if(l)call draw(c) ; OK ' ':call draw(c) ; OK 'c':c ꞉＝ c+1 ; if(c ＝ M)c ꞉＝ 0 ; OK 'd':call draw(15) ; OK 'f':call fill(y,x,c,Z) ; OK 's':call save(y,x) ; OK 'q':v ꞉＝ 0 ; OK 'v':c ꞉＝ c-1 ; if(c ＝ N)c ꞉＝ M-1 ; CALL display(y,x,c) end end ; procedure main(I c,packed ʌ ʌ v) ; begin call start ; call getmaxyx(stdscr,w,q) ; if(w>M)w ꞉＝ M ;if(q>M)q ꞉＝ M ; call start_color ; while(x<M)do begin call init_pair(x,x,x) ; x ꞉＝ x+1 end ; LOOP call draw(15) POOL ; if(c ＝ 2)call load(v[c-1]) ; call display(0,0,0) ; call m ; call endwin end ; call main． Through this code, perhaps many netizens bluntly said that this is not C code, but contains all the features of the Pascal language, using a semicolon as a statement separator instead of a statement ending, using ":=" to indicate assignment, and perhaps some LOOP of Algol (an instructional programming language) ... POOL syntax. It even has the return assignment of the Pascal language, which assigns a value to a function, which is its return value.
However, Brian Robert Callahan explains that Arthur Whitney, developers of the recently heard that A+, K, and Q (which are array programming languages such as APL and J) would use a C preprocessor to create his own language and then implement his own language with this custom language. So he decided to try this interesting experiment.
Brian Robert Callahan wrote a compiler based on a custom language based on PL/0. The highlight of this exercise is that the C compiler understands UTF-8 characters as valid characters for identifiers. Brian Robert Callahan uses a lot of characters that look like ASCII (American Standard Code for Information Interchange), which is not actually ASCII and is eventually accepted as a valid identifier. The C preprocessor does a good job of converting these identifiers into corresponding instructions. The hidden header files can be seen here.
If you want to see how your C code really looks, try running:
$ cc -E cpaint.c | clang-format | less If you're interested, try the program above!
Original link: https://briancallahan.net/blog/20220220.html
