Rosetta Code

Execute Brain****/D: Difference between revisions

Page Discussion

Execute Brain****/D (view source)

Revision as of 23:51, 24 March 2012

212 bytes added ,  12 years ago
Version 1 updated
(Move 2 alternate implementations from Execute Brain****. http://rosettacode.org/mw/index.php?title=Execute_Brain****&action=history)
(Version 1 updated)
Line 1:
{{implementation|Brainf***}}{{collection|RCBF}}
 
== Implementation=Version 1 ===
{{works with|D|2.007+}}
An implementation of Rosetta Code [[Brainfuck|BrainF*ck]] interpreter in [[D]].
Implement notes:
*Needs D version 2.007+, because [[closure]] support is required (it should compile in D1, but will run abnormally if brackets/loop-commands are in the BF source).
*Memory is represented by an [[associative array]], so that negative addresses are allowed, though it is not efficient.
*Input and output are in character mode, rather than in numerical.
*Nesting level is checked during parsing, and if loops/brackets are not matched, an error is thrown before executing the code.
<lang d>import core.stdc.stdio, core.stdc.stdlib, std.file;
<lang d>module rcbf ;
import std.file, std.c.stdio ;
 
alias void delegate() Act ;
 
__gshared char[int] mem ; // memory
__gshared int ptr ; // mem pointer▼
__gshared Act[char] cmd ; // bf command except loop-control
▲int ptr ; // mem pointer
 
static this() {
cmd['>'] = { if (!(++ptr in mem)) mem[ptr] = 0 ; } ;
cmd['<'] = { if (!(--ptr in mem)) mem[ptr] = 0 ; } ;
cmd['+'] = { mem[ptr] += 1 +; } ;
cmd['-'] = { mem[ptr] -= 1 -; } ;
cmd['.'] = { printfputchar("%c", mem[ptr]) ; } ;
cmd[','] = { printf("%c", mem[ptr] = getch()) ; flushall ; } ;
int c = getc(stdin);
if if(ccc in== cmdEOF)▼
break exit(1);▼
mem[ptr] = cast(char)c;
} ;▼
}
 
void bf(in string code) {
int cp = 0 ; // code pointer
int nested = 0 ; // nested loop level
 
Act bfAct() {
Act[] acts ; // store commands of current nesting level
char cc ; char cc;
while(cp < code.length)▼
switch(cc = code[cp++]) { // cc get next command and code pointer cp is advanced
case '[':▼
nested++ ;▼
acts ~= bfAct() ; // begin inner loop▼
▲ break ;
case ']': ▼
if(--nested < 0) throw new Exception("Unmatched Loops") ;▼
return { while(mem[ptr]) { foreach(x ; acts){x();} } } ;
default:▼
▲ if(cc in cmd)
acts ~= cmd[cc] ;▼
//else ignore other non-command char▼
▲ }
return { foreach(x ; acts){x();} } ;▼
}▼
mem = null ; mem[0] = 0 ; ptr = 0 ; // reset memory
Act run = bfAct() ;▼
if(nested != 0) throw new Exception("Unmatched Loops") ;▼
run() ; // execute the whole bf program▼
printf("\n") ;▼
}
 
▲ while (cp < code.length) {
void main(string[] args) { // if no argument, demo code will be run, else ▼
if(args.length > 1) // thecc get argumentsnext arecommand treatedand ascode filenamespointer ofcp bfis sourceadvanced
foreach(f ; args[1..$]) // andcc executed= one by one.code[cp];
try bf(cast(string)read(f)) cp++;
catch (Exception e) printf switch ("%*s",e.msgcc) ;{
▲ case '[':
else ▼
▲ nested++ ;
bf(">+++++++++[<+++++++++>-]<+.>+++[<----->-]"▼
▲ acts ~= bfAct() ; // begin inner loop
"<.-.++++.>++++++[<------>-]<--.>++++++++["▼
break;
"<+++++++++>-]<+.>++[<++>-]<+.>++++++++[<-"▼
 
"-------->-]<------.>++++++[<++++++>-]<.>+"▼
"++++[<------->-]<.") ; case ']':
nested--;
if (nested < 0)
▲ if(nested != 0) throw new Exception("Unmatched Loops") ;
return {
while (mem[ptr]) {
foreach (x; acts)
x();
▲ case ']': }
};
 
▲ default:
if (cc in cmd)
▲ acts ~= cmd[cc] ;
▲ // else ignore other non-command char
}
}
 
return {
▲ return { foreach (x ; acts){x();} } ;
x();
};
▲ }
 
// reset memory
mem = null;
mem[0] = 0;
ptr = 0;
 
▲ Act run = bfAct() ;
if (nested != 0)
▲ if(--nested < 0) throw new Exception("Unmatched Loops") ;
▲ run() ; // execute the whole bf program
▲ printf("\n") ;
}
 
</lang>▼
 
void main(in string[] args) {
▲void main(string[] args) { // if no argument, demo code will be run, else the first
// argument is treated as filename of bf source and executed.
if (args.length > 1) {
bf(readText(args[1]));
▲ } else {
▲ bf(">+++++++++[<+++++++++>-]<+.>+++[<----->-]"
▲ " <.-.++++.>++++++[<------>-]<--.>++++++++["
▲ " <+++++++++>-]<+.>++[<++>-]<+.>++++++++[<-"
▲ " -------->-]<------.>++++++[<++++++>-]<.>+"
++++[<------->-]<.");
}
▲}</lang>
 
== Implementation 2 ==
Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/64565"