C-INTERCAL Bug and To-Do list

### Critical Bugs

src/ick_ec.h — Macro label collision risk

src/ick_ec.h uses labels like ick_l1_ICK_EC_PP_1, ick_l2_ICK_EC_PP_2,
ick_l6_ICK_EC_PP_6 generated from macro parameters. If the id parameter contains
characters that produce invalid C identifiers, or if two invocations produce the same
label, this breaks. The ICK_EC_PP_6 reference in ick_startup hardcodes 6 but the label
name uses the macro parameter id, creating a potential mismatch.

src/ick_lose.c — exit(atoi(m)) has no error handling

src/ick_lose.c:48

exit(atoi(m));

atoi returns 0 on failure and has no way to distinguish "the string starts with 0" from
"the string is not a number". If a message string is corrupted or truncated, the exit
code will be silently wrong.

src/uncommon.c — Static buffer not thread-safe

src/uncommon.c:52,100

Both ick_findandfopen() and ick_findandtestopen() use static char buf2[BUFSIZ]. If the
compiler is used from a multithreaded context (e.g., as a library), concurrent calls
will corrupt each other's buffers.

src/lexer.l — getc() override breaks FILE* semantics

src/lexer.l:100-168

The lexer overrides getc() globally. This means any code calling getc() will
inadvertently use the lexer's custom getc() that handles INTERCAL line continuation.
This is a dangerous global side effect. The correct approach would be to use fgetc()
with a custom FILE* or rename the override.

src/unravel.c — Heavy setjmp/longjmp abuse

src/unravel.c uses setjmp/longjmp extensively to implement multithreading and computed
COME FROM. The comments acknowledge this:

> "setjmp/longjmp is worse than goto in terms of spaghettification of code."

Jumping into the middle of uninitialized stack frames in degenerated C code (which
didn't exist when libickmt.a was compiled) is undefined behavior on many platforms. The
longjmp to a target that hasn't executed the corresponding setjmp is specifically
listed as UB in C11 7.13.2.1.

### Code Quality Issues

src/dekludge.c — Magic constants in abstainmatch()

src/dekludge.c:112-125

static int abstainmatch(int npconstant, int tptype)
{
    if(npconstant == tptype) return 1;
    if(npconstant == ABSTAIN)
      if(tptype == FROM || tptype == MANYFROM || tptype == DISABLE) return 1;
    ...
}

The constants ABSTAIN, REINSTATE, GETS, FROM, MANYFROM, DISABLE, ENABLE, RESIZE,
UNKNOWN, SPLATTERED are magic numbers with no inline documentation of their values.

src/ick_ec.h — Complex goto macro patterns are unmaintainable

The ICK_EC_FUNC_START/ICK_EC_FUNC_END macros and related macros (ick_linelabel,
ick_comefrom, ick_nextfrom, etc.) use goto-based control flow that is extremely
difficult to reason about. The labels are generated from macro parameters, making them
hard to debug. A cleaner approach would use function pointers or state machines.

src/feh2.c — emit() function is overly complex

The emit() function in src/feh2.c is ~1500 lines and handles code generation for all
INTERCAL statement types in a single massive switch. This makes it hard to verify
correctness for any single statement type.

src/oil.y — Memory leak on parser error

src/oil.y uses BINARYEXPR and UNARYEXPR macros that call malloc for each node in the
parse tree. On parser error paths, treefree() is called, but the tofree/tfi mechanism
(used for lexer-allocated strings) is not cleaned up if the parser fails mid-way.

src/pick2.h — ick_roll() is a terrible randomizer

src/pick2.h:116

ICK_INT1 ick_roll(ICK_INT8 n)
{
   return n>50;
}

This returns a pseudo-random value based solely on the input parameter n > 50. It has
no internal state, so calling it with the same argument always returns the same result.
This is likely intentional for PIC simplicity, but it should be documented.

### Suggestions for Improvement

 Priority    Area                        Suggestion
──────────  ──────────────────────────  ───────────────────────────────────────────────
 High        ick_ec.h macros             Replace goto-based macros with state-machine
                                         or function pointer approach
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Medium      unravel.c longjmp           Document which platforms are supported and
                                         add runtime guards
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Medium      getc() override             Rename to ick_getc() or use a custom FILE*
                                         wrapper
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Medium      pick2.h typo                Fix syslipopt1500 → syslibopt1500
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Medium      abstainmatch()              Add a comment table mapping constants to
                                         values
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Low         emit() complexity           Split into per-statement-type helper
                                         functions
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Low         oil.y error cleanup         Add explicit error path that frees the parse
                                         tree
──────────  ──────────────────────────  ───────────────────────────────────────────────
 Low         ick_roll() documentation    Document that it's deterministic for a given
                                         input