SKILL.md
SysY Testcase Conversion Workflow
You are an expert compiler engineer. Your goal is to convert standard C/C++ competitive programming code into Strict SysY (a simplified C subset) and generate valid test data.
Non-Negotiable Grammar Rules
Adhere to these rules strictly. Read references/sysylanggrammar.md only if you encounter an obscure syntax edge case not covered here.
| Feature | Constraint | Fix / Refactor | ||||||
|---|---|---|---|---|---|---|---|---|
| Prototypes | Implicit | Do NOT write int getint(); or int printf(...);. |
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| Memory / Size | Max 4MB Total (MARS Limit) | Scale Down Constants. 1e6 $\to$ 1e4. Total int elements < 500,000. |
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| Preprocessor | BANNED (#include, #define, #ifdef) |
Use const int for constants. Delete imports. |
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| Types | int, void ONLY |
No long long, float, double, char, bool. |
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| Pointers | BANNED (int p, &x, ptr) |
Pass arrays as int a[]. Use return values for scalar outputs (no void f(int *res)). |
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| Arrays | 1D Arrays ONLY | Flatten int a[N][M] $\to$ int a[N*M]. No VLAs. |
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| Loops | for loops ONLY. No declarations inside () |
Move vars out: int i; for(i=0;...). No do-while. No while. turn while(1) into for(;;). |
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| Returns | Non-void funcs MUST return | Add dummy return 0; at end of function, even after infinite loops. |
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| Conditions As Values | Exp → AddExp (arithmetic only) |
Do NOT use relational / logical expressions as values, e.g. return a < b; or x = (a < b);. Rewrite: if (a < b) return 1; return 0; or x = 0; if (a < b) x = 1;. |
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| Input | int getint() ONLY |
No scanf, cin, getchar. |
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| Output | printf ONLY |
Format string is a SysY StringConst: only %d is allowed as a format placeholder, and the only escape sequence is \n (backslash may appear only in \n). No other format specifiers/modifiers (e.g. %c, %s, %%, %05d) and no other escapes (e.g. \\, \", \t, \r, \0). Ensure the number of , Exp arguments equals the number of %d. |
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| Parentheses | PrimaryExp → '(' Exp ')' and Exp → AddExp |
(...) as an expression can wrap arithmetic only. Besides mandatory syntax like if (Cond) / for (...; Cond; ...), do NOT add extra parentheses around conditions (any `== != < > <= >= && |
!). Rewrite via precedence/distribution, e.g. if (t2 > 0 && (a == 42 |
a == 47)) $\to$ if (t2 > 0 && a == 42 |
t2 > 0 && a == 47)`. | |||
| Operators | No Bitwise (<<, >>, &, ` |
, ^`) |
Use arithmetic: *2, /2, %2. Use lookup tables. |
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| Structs | BANNED | Split into parallel arrays (e.g., x[N], y[N]). |
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| Globals | Encouraged for large arrays | Prevent stack overflow in SysY runtime, keep totol size < 4MB. | ||||||
| Input Data | Strictly 1 Integer Per Line (in.txt) |
No spaces (1 2). Must be 1\n2. Matches MIPS syscall. If testfile.txt uses a sentinel to stop reading (e.g., if (ch == 0) break;, while (x != 0), while (1) { x=getint(); if (x==0) break; }), then in.txt must explicitly include that sentinel value as the last integer. Do not rely on EOF behaving like 0: SysY MIPS getint() is implemented via syscall 5 and does not implement “EOF → 0”. |
Execution Protocol
Follow these steps sequentially.
Step 1: Initialize
Use the helper script to create the directory and placeholder files.
python3 .codex/skills/create-sysy-testcase/scripts/init_case.py <TARGET_DIR>Step 2: Write Logic (The Intelligence Part)
Translate the source logic into Strict SysY. Focus your "thinking" here.
- Scale Down: If original code has
MAXN = 100000, change it smaller to fix up to MARS's address space limit(about 4MB). Ensure logic consistency. - Refactor logic to fit the constraints above (e.g., flatten 2D arrays).
- Write the code to
testfile.txt. - Write input data to
in.txt(newline-separated integers only) matching your scaled-down size. If the program reads until a sentinel (e.g.,0) rather than a known count, put that sentinel explicitly as the last integer; do not rely on EOF.
cat <<'EOF' > <TARGET_DIR>/testfile.txt
// ... your converted SysY code ...
EOF
cat <<'EOF' > <TARGET_DIR>/in.txt
// ... your input numbers ...
EOFStep 3: Compile, Run & Verify
Use the runner script. It automatically wraps your code with C headers, compiles it (gcc/clang), runs it against in.txt, and generates ans.txt.
python3 .codex/skills/create-sysy-testcase/scripts/run_case.py <TARGET_DIR>Step 4: Fix & Retry
If Step 3 reports a COMPILE ERROR or RUNTIME ERROR:
- Read the error output.
- Fix the logic in
testfile.txt. - Rerun Step 3.
Translation Strategy Tips
- SysY input (
in.txt) must be newline-separated integers. - If the original problem uses strings (e.g., "PUSH", "POP"), map them to integers (e.g., 1, 2) in your translation logic.
- MIPS Compatibility Check:
in.txtmust not contain spaces between numbers. - Never use EOF as a terminator: if the program’s input loop expects a terminator value (commonly
0, sometimes-1/-999), put that value explicitly at the end ofin.txt(and keep it on its own line). - Strengthen
in.txtslightly: prefer including a mix of small/edge values (e.g.,0/1/-1, min/max for scaled constraints) and a few typical values, while still matching the program’s expected format and counts; always end the file with a trailing newline.