First working version

.gitignore

@@ -1 +1,2 @@
 lib/.precomp
+test.p6

META.info → META6.json

@@ -3,7 +3,8 @@
     "name"         : "Inline::Brainfuck",
     "version"      : "1.001001",
     "description"  : "Use Brainfuck language in your Perl 6 programs",
-    "test-depends" : [ "Test" ],
+    "depends"      : [ "Term::termios" ],
+    "test-depends" : [ "Test", "Test::Output" ],
     "provides"     : {
         "Inline::Brainfuck" : "lib/Inline/Brainfuck.pm6"
     },

README.md

@@ -7,10 +7,29 @@ Inline::Brainfuck - Use Brainfuck language in your Perl 6 programs
 # SYNOPSIS
 
 ```perl6
+use lib 'lib';
+use Inline::Brainfuck;
+
+brainfuck '++++++++++ ++++++++++ ++++++++++ +++.'; # prints "!"
 ```
 
 # DESCRIPTION
 
+This module provides a subroutine that takes a string with
+[Brainfuck code](https://en.wikipedia.org/wiki/Brainfuck) and executes it.
+
+# EXPORTED SUBROUTINES
+
+## `brainfuck`
+
+```perl6
+    brainfuck '++++++++++ ++++++++++ ++++++++++ +++.'; # prints "!"
+```
+
+Takes an `Str` with Brainfuck code to execute. Input will be read
+from STDIN. The terminal will be switched to non-buffered mode, so any input
+will be processed immediatelly, per-character. Output will be sent to STDOUT.
+
 ----
 
 # REPOSITORY

examples/brainfuckit.p6

@@ -2,3 +2,5 @@
 
 use lib 'lib';
 use Inline::Brainfuck;
+
+brainfuck 't/bf-programs/hello-world.bf'.IO.slurp;

lib/Inline/Brainfuck.pm6

@@ -1,7 +1,61 @@
-unit class Inline::Brainfuck;
+unit module Inline::Brainfuck:ver<1.001001>;
+use Term::termios;
 
-has $!state = Inline::Brainfuck::State.new;
+sub brainfuck (Str:D $code) is export {
+    check-matching-loop $code;
+    my $saved-term;
+    try {
+        $saved-term = Term::termios.new(:1fd).getattr;
+        given Term::termios.new(:1fd).getattr {
+            .makeraw;
+            .setattr(:DRAIN);
+        }
+    };
+    LEAVE { try $saved-term.setattr(:DRAIN) }
 
-method run (Str:D $code) {
-    $code.subst-mutate: /<-[-<>+.,[\]]>/, '', :g;
+    my @code    = $code.comb: /<[-<\>+.,[\]]>/;
+    my $ꜛ       = 0;
+    my $cursor  = 0;
+    my $stack   = Buf[uint8].new: 0;
+    loop {
+        given @code[$cursor] {
+            when '>' { $stack.append: 0 if $stack.elems == ++$ꜛ;       }
+            when '<' { $ꜛ--; fail "Negative cell pointer\n" if $ꜛ < 0; }
+            when '+' { $stack[$ꜛ]++;               }
+            when '-' { $stack[$ꜛ]--;               }
+            when '.' { $stack[$ꜛ].chr.print;       }
+            when ',' { $stack[$ꜛ] = $*IN.getc.ord; }
+            when '[' {
+                $cursor++; next if $stack[$ꜛ];
+                loop {
+                    state $level = 1;
+                    $level++ if @code[$cursor] eq '[';
+                    $level-- if @code[$cursor] eq ']';
+                    last unless $level;
+                    $cursor++;
+                }
+            }
+            when ']' {
+                unless $stack[$ꜛ] { $cursor++; next }
+                loop {
+                    state $level = 1;
+                    $cursor--;
+                    $level-- if @code[$cursor] eq '[';
+                    $level++ if @code[$cursor] eq ']';
+                    last unless $level;
+                }
+            }
+        }
+        last if ++$cursor > @code.elems;
+    }
+}
+
+sub check-matching-loop ($code) {
+    my $level = 0;
+    for $code.comb {
+        $level++ if $_ eq '[';
+        $level-- if $_ eq ']';
+        fail qq{Closing "]" found without matching "["\n} if $level < 0;
+        LAST { fail 'Unmatched [ ]' if $level > 0 }
+    }
 }

t/01-output.t

@@ -0,0 +1,18 @@
+#!perl6
+
+use lib 'lib';
+use Test;
+use Test::Output;
+use Inline::Brainfuck;
+
+output-is {
+    brainfuck '++++++++++ ++++++++++ ++++++++++ ++++++++++'
+        ~ '++++++++++ ++++++++++ ++++++++++ ++.';
+}, "H", 'Output letter "H"';
+
+output-is {
+    brainfuck 't/bf-programs/hello-world.bf'.IO.slurp;
+}, "Hello World!\n", 'Hello world! program works';
+
+
+done-testing;

t/02-input-test.t

@@ -0,0 +1,21 @@
+#!perl6
+
+use lib 'lib';
+use Test;
+use Test::Output;
+use Inline::Brainfuck;
+
+unless %*ENV<INTERACTIVE_TESTING> {
+    diag "INTERACTIVE_TESTING env var not set. Skipping this test";
+    done-testing;
+    exit;
+}
+
+diag 'Type word "test" (press ENTER if nothing happens right after you type it)';
+
+output-is {
+    brainfuck 't/bf-programs/input1.bf'.IO.slurp;
+}, "test", 'input -> output program works';
+
+
+done-testing;

t/bf-programs/hello-world.bf

@@ -0,0 +1,43 @@
+[ This program prints "Hello World!" and a newline to the screen, its
+  length is 106 active command characters. [It is not the shortest.]
+
+  This loop is a "comment loop", a simple way of adding a comment
+  to a BF program such that you don't have to worry about any command
+  characters. Any ".", ",", "+", "-", "<" and ">" characters are simply
+  ignored, the "[" and "]" characters just have to be balanced. This
+  loop and the commands it contains are ignored because the current cell
+  defaults to a value of 0; the 0 value causes this loop to be skipped.
+]
++++++ +++               Set Cell #0 to 8
+[
+    >++++               Add 4 to Cell #1; this will always set Cell #1 to 4
+    [                   as the cell will be cleared by the loop
+        >++             Add 2 to Cell #2
+        >+++            Add 3 to Cell #3
+        >+++            Add 3 to Cell #4
+        >+              Add 1 to Cell #5
+        <<<<-           Decrement the loop counter in Cell #1
+    ]                   Loop till Cell #1 is zero; number of iterations is 4
+    >+                  Add 1 to Cell #2
+    >+                  Add 1 to Cell #3
+    >-                  Subtract 1 from Cell #4
+    >>+                 Add 1 to Cell #6
+    [<]                 Move back to the first zero cell you find; this will
+                        be Cell #1 which was cleared by the previous loop
+    <-                  Decrement the loop Counter in Cell #0
+]                       Loop till Cell #0 is zero; number of iterations is 8
+
+The result of this is:
+Cell No :   0   1   2   3   4   5   6
+Contents:   0   0  72 104  88  32   8
+Pointer :   ^
+
+>>.                     Cell #2 has value 72 which is 'H'
+>---.                   Subtract 3 from Cell #3 to get 101 which is 'e'
++++++++..+++.           Likewise for 'llo' from Cell #3
+>>.                     Cell #5 is 32 for the space
+<-.                     Subtract 1 from Cell #4 for 87 to give a 'W'
+<.                      Cell #3 was set to 'o' from the end of 'Hello'
++++.------.--------.    Cell #3 for 'rl' and 'd'
+>>+.                    Add 1 to Cell #5 gives us an exclamation point
+>++.                    And finally a newline from Cell #6

t/bf-programs/input1.bf

@@ -0,0 +1,3 @@
+,>,>,>, # Read in word "test"
+<<<     # Rewind back to start
+.>.>.>. # Print word test back