Add ReasoningParser

[junya-takayama]

Add a mechanism to the VLLM and HuggingFaceLM classes to extract the reasoning content and store it in LMOutput.reasoning_text.

Example

flexeval_lm --eval_setup rakuda-v2-ja --language_model VLLM --language_model.model Qwen/Qwen3-4B --language_model.reasoning_parser UnifiedRegexReasoningParser --language_model.reasoning_parser.pattern="<think>(?P<reasoning_content>.*?)</think>(?P<content>.*)"

...
2026-05-21 21:04:48.236 | INFO     | flexeval.core.evaluate_chat_response:evaluate_chat_response:181 - Example of the output
2026-05-21 21:04:48.236 | INFO     | flexeval.core.evaluate_chat_response:evaluate_chat_response:182 - {
    "lm_output": {
        "text": "\n\n四国地方には以下の4つの都道府県があります。それぞれの県庁所在地を以下に列挙します。\n\n1. **香川県（かわかん）**  \n   - **県庁所在地**：香川市（かわかし）\n\n2. **岡山県（おうさんけん）**  \n   - **県庁所在地**：岡山市（おうさんし）\n\n3. **徳島県（とくしまけん）**  \n   - **県庁所在地**：徳島市（とくしまし）\n\n4. **広島県（ひろしまけん）**  \n   - **県庁所在地**：広島市（ひろしまし）\n\n※四国地方は日本の四つの地方の一つで、これらの4県が含まれます。",
        "raw_text": "<think>\nOkay, the user is asking for the four prefectures in the Shikoku region and their respective prefectural capitals. Let me start by recalling the four prefectures in Shikoku. I think they are Kagawa, Okayama, Tokushima, and Hiroshima. Wait, but I need to make sure. Let me think again. Shikoku is the fourth largest island in Japan, right? The four prefectures there are Kagawa, Okayama, Tokushima, and Hiroshima. Yes, that's correct.\n\nNow, the prefectural capitals. For Kagawa, I believe the capital is Kagawa City. Okayama's capital is Okayama City. Tokushima's capital is Tokushima City. And Hiroshima's capital is Hiroshima City. Let me double-check each one to be sure. Kagawa City is indeed the capital of Kagawa Prefecture. Okayama City is the capital of Okayama Prefecture. Tokushima City is the capital of Tokushima Prefecture. Hiroshima City is the capital of Hiroshima Prefecture. That seems right. \n\nWait, but sometimes people might confuse the capitals. For example, Hiroshima is a major city, but is it the capital? Yes, Hiroshima City is the capital of Hiroshima Prefecture. Okay, so the answer should be the four prefectures and their capitals as listed. I think that's all. Let me just confirm once more. Yes, those are the four prefectures in Shikoku, and their capitals are as mentioned. No mistakes there.\n</think>\n\n四国地方には以下の4つの都道府県があります。それぞれの県庁所在地を以下に列挙します。\n\n1. **香川県（かわかん）**  \n   - **県庁所在地**：香川市（かわかし）\n\n2. **岡山県（おうさんけん）**  \n   - **県庁所在地**：岡山市（おうさんし）\n\n3. **徳島県（とくしまけん）**  \n   - **県庁所在地**：徳島市（とくしまし）\n\n4. **広島県（ひろしまけん）**  \n   - **県庁所在地**：広島市（ひろしまし）\n\n※四国地方は日本の四つの地方の一つで、これらの4県が含まれます。",
        "reasoning_text": "\nOkay, the user is asking for the four prefectures in the Shikoku region and their respective prefectural capitals. Let me start by recalling the four prefectures in Shikoku. I think they are Kagawa, Okayama, Tokushima, and Hiroshima. Wait, but I need to make sure. Let me think again. Shikoku is the fourth largest island in Japan, right? The four prefectures there are Kagawa, Okayama, Tokushima, and Hiroshima. Yes, that's correct.\n\nNow, the prefectural capitals. For Kagawa, I believe the capital is Kagawa City. Okayama's capital is Okayama City. Tokushima's capital is Tokushima City. And Hiroshima's capital is Hiroshima City. Let me double-check each one to be sure. Kagawa City is indeed the capital of Kagawa Prefecture. Okayama City is the capital of Okayama Prefecture. Tokushima City is the capital of Tokushima Prefecture. Hiroshima City is the capital of Hiroshima Prefecture. That seems right. \n\nWait, but sometimes people might confuse the capitals. For example, Hiroshima is a major city, but is it the capital? Yes, Hiroshima City is the capital of Hiroshima Prefecture. Okay, so the answer should be the four prefectures and their capitals as listed. I think that's all. Let me just confirm once more. Yes, those are the four prefectures in Shikoku, and their capitals are as mentioned. No mistakes there.\n",
...

[Kotaro-Aono]

ここではtoolのところにある

            if lm_output.text is None:
                continue

的な処理はいらないんですかね？

[junya-takayama]

そもそもtool, reasoning でfor文分かれてる意味ないなと思ったのでまとめた上で一番上にセットしました！
https://github.com/sbintuitions/flexeval/pull/287/changes#diff-9c4eb04cb0e3beb9678e4067391a29b6bfb2c25b6f1cf1de4729ddb6dba932deR429-R431

[Kotaro-Aono]

resoning parserとtool_parserの同時使用って想定されていますか？
想定しているなら下でraw_textとかが上書きされてしまうのでまずい気がします

[junya-takayama]

同時使用はあり得ます。
想定としては raw_text は何であれ後処理が入る前のテキストが入るので、そうなるように修正しました
（commit 操作ミスって色々くっついちゃいましたが…）

https://github.com/sbintuitions/flexeval/pull/287/changes#diff-9c4eb04cb0e3beb9678e4067391a29b6bfb2c25b6f1cf1de4729ddb6dba932deR435-R437

base.py: https://github.com/sbintuitions/flexeval/pull/287/changes#diff-3f56c1a60f9931bd179b6a566c4391ce34db99296812dc1590020d26de1f69aaR240-R243

[junya-takayama]

@Kotaro-Aono レビューありがとうございます！諸々対応しました

[Kotaro-Aono]

ここが悪さしてそうです
reasoning_text == None
raw_output == "no think tags here"
なので

[Kotaro-Aono]

LGTM！