From 530cab90d361fddfa5dfeaae16e8d3167918032f Mon Sep 17 00:00:00 2001
From: anon <anon@anon.anon>
Date: Tue, 10 Dec 2024 20:39:01 +0100
Subject: [PATCH] Added 'C_C++/flex/brainfuck.c'

---
 C_C++/flex/brainfuck.c | 141 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 C_C++/flex/brainfuck.c

diff --git a/C_C++/flex/brainfuck.c b/C_C++/flex/brainfuck.c
new file mode 100644
index 0000000..5191592
--- /dev/null
+++ b/C_C++/flex/brainfuck.c
@@ -0,0 +1,141 @@
+/* @BAKE
+    re2c -W -o $*.re.c $@
+    gcc -o $* $*.re.c -ggdb
+    ./$* pure_hw.bf
+   @STOP
+ */
+#include <stdio.h>
+
+char data[30000];
+char * data_ptr = data;
+
+// #define YYDEBUG(n, c) fprintf(stderr, "rule %n (%c)\n", l, c)
+
+/* Review of this bullshit software called re2c 3.1:
+ *  + the comment thing is kinda smart
+ *    - it generates very small scanners so having them inline is not insanity
+ *    - you can nest them in your source, without breaking your highlighting or making the lls cry
+ *  + it can generate state transition graphs, thats kinda cool
+ *  + neither the "free-form" or the "function-like" API seems to work;
+ *     theres no error or acknoledgement either
+ *  + the first example in the documentation is fucking broken
+ *    - it uses undocumented cli flags (like some others)
+ *    - they feed a string, but only one character is ever evaluated
+ *  + '\00' gives a syntax error for no damn reason
+ *  + switches it generates hurt my eye. why the fuck do they need a label and a goto for each case?,
+ *     sure there is string/regex matching which cannot fit inside a case,
+ *     however what if only those were to jmp?
+ *  + the default rule ('*') is not properly documented
+ *  + for whatever reason fallthough is the default behaviour so you have to spam either
+ *     continue or goto
+ *  + the default default rule is a fallthrough too;
+ *     not a jam, but whatever rule the transpiler decided to insert to the top
+ *     (spoiler alert: they are not even in the order of declaration)
+ *  + what the literal fuck is this syntax?
+ *     `re2c:api:style`
+ *     1) you dont need the prefix re2c, its utter bloat
+ *     2) namespacing for 20 or so options???
+ *     3) my bad, *should be 20 so optoins, instead we have shit like this:
+ *          re2c:bit-vectors, re2c:flags:bit-vectors, re2c:flags:b
+ *        to do the same fucking thing
+ *        and just to stress this, they have namespaces, but you can just no use them.
+ *        when? option dependent.
+ *  + do we have comments inside re2c blocks? dunno. not documented.
+ *  + the cli help is too verbose; useless line breaks makes it hard to grep
+ *  + while we are at it, why do we need so many fucking options?
+ *      $ re2c --help | grep -e '^\W*-' | sort | uniq | wc -l
+ *      77
+ *      $ flex --help | grep -e '^\W*-' | sort | uniq | wc -l
+ *      46
+ *      # and this shit is suppose to be smaller
+ *  + -d is useless; YYDEBUG is simply not fit to tracing, since it does not tell you
+ *    which lexer it is or the line number
+ *  + i get duplicate output. now, it very well might be my fault,
+ *     however i have no proper means of debugging and im not
+ *     wasting more time on this software
+ */
+
+int yylex(const char * const s) {
+    const char * YYCURSOR = s;
+
+  INITIAL:
+    while (*YYCURSOR)
+        /*!re2c
+        re2c:yyfill:enable = 0;
+        re2c:define:YYCTYPE = char;
+
+        '>'     { ++data_ptr; continue; }
+        '<'     { --data_ptr; continue; }
+        '+'     { ++(*data_ptr); continue; }
+        '-'     { --(*data_ptr); continue; }
+        '.'     { putchar(*data_ptr); continue; }
+        ','     { *data_ptr = getchar(); continue; }
+        '['     {
+                  if (!*data_ptr) {
+                       goto IN_SKIP_FORWARD;
+                  }
+                  continue;
+                }
+        ']'     {
+                  if (!*data_ptr) {
+                       goto IN_SKIP_BACKWARD;
+                  }
+                  continue;
+                }
+        *       { continue; }
+        '\x00'  { return 0; }
+        */
+
+  IN_SKIP_FORWARD:
+    while (*YYCURSOR)
+        /*!re2c
+
+        ']'     {
+                  goto INITIAL;
+                }
+        *       { continue; }
+        '\x00'  { return 0; }
+         */
+    /* I cant seem to make this thing go backwards,
+     *  so everything is broken
+     */
+  IN_SKIP_BACKWARD:
+  #define YYSKIP --YYCURSOR
+    while (*YYCURSOR)
+        /*!re2c
+        //re2c:api:style     = free-form;
+        //re2c:define:YYSKIP = "--YYCURSOR;";
+
+        '['     {
+                  ++YYCURSOR;
+                  goto INITIAL;
+                }
+        *       { continue; }
+        '\x00'  { return 0; }
+         */
+
+    return 0;
+}
+
+signed main(int argc, char * argv[]) {
+    if (argc != 2) {
+        printf("%s <file>", argv[0]);
+        return 1;
+    }
+
+	FILE* f = fopen(argv[1], "r");
+	if(!f){ return 2; }
+
+	fseek(f, 0, SEEK_END);
+	int flen = ftell(f);
+	rewind(f);
+	char fstr[flen+1];
+	fstr[flen] = '\00';
+	fread(fstr, flen, sizeof(char), f);
+
+	fclose(f);
+
+    yylex(fstr);
+
+    return 0;
+}