gh-149026: Add colour to pickletools CLI output

[hugovk]

Create a pickle file, for example:

importpickledata= {
"a": [1, 2.0, 3+4j],
"b": ("character string", b"byte string"),
"c": {None, True, False},
}
withopen("data.pickle", "wb") asf:
pickle.dump(data, f, protocol=5)

Then ./python.exe -m pickletools data.pickle:

• Issue: Add colour to pickletools CLI output #149026

---

📚 Documentation preview 📚: https://cpython-previews--149027.org.readthedocs.build/

[hugovk]

Aside: the alignment is the same in main without colour, and the code says:

# make a mild effort to align arguments
...
# make a mild effort to align annotations
...

If someone's up for making a bit less mild effort in another PR, go for it!

[picnixz]

Can we have the instruction names in white (no color)? I find it less readable with colors as all instructions have the same color.

[hugovk]

Like this?

Or I think bold cyan is better?

[picnixz]

IMO, too many colors hurt more than they help. White is not that good either actually... I do like the colors for literals and the first column but I feel that colors for instruction names are always too much because it's just adding colors to words that will anyway be classified identically.

Alternatively, how about some "dead" words such as MARK/NONE etc and add categorize the opcodes themselves into colorized categories. This could help a bit more visually (e.g., I want to locate all MARK, whether I use colors or not now I won't be able to find it easily without a CTRL+F).

[hugovk]

Something like this?

[picnixz]

Much better IMO! I would suggest not having colors for opcodes that have a colored literal (like SHORT_BINUNICODE). WDYT?

[hugovk]

---

Or we could stripe it to match the value? But give the mild attempt at alignment, maybe they're a bit too close.

[picnixz]

Or we could stripe it to match the value? But give the mild attempt at alignment, maybe they're a bit too close.

It would require a bit more effort to parse the literal in this case. I think the no-color option is better IMO. FTR, the MARK can be in gray as the PROTO because each MARK is followed by an indent I thnk.

[hugovk]

MARK in grey:

[picnixz]

I like those colors, at least they are more readable to me (and I have very poor eyesight). What about light theme though?

[hugovk]

[picnixz]

I find the colors much readable now! thanks for the work

[hugovk]

@picnixz Any further comments or ready to merge?

[picnixz]

Quick question but can be done in a follow-up:

• Are those valid for any pickle protocol version?
• Check that the OP codes are valid using opcodes. It contains all opcodes + their protocol versions. You can use name2i but you need to remove the del name2i above in the file. Or you can build this list closer to name2i (L2200)

[picnixz]

Alternative: add a "category" to the opcode objects. Thankfully, those objects are not tuples so we can't break things.

[hugovk]

Yes, it covers all protocol versions. Adding a "category" is an interesting idea, but not sure this should be part of the public API. I've gone for the first suggestion.

[picnixz]

Well, you can always make it a private attribute :) but it's not really important I think. We can revisit this later. It's only a burden when we create the list. But adding new opcodes is usually not common so... it's not really important.

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32468999 | 📁 Comparing 5338435 against main (1e7dfbc)

🔍 Preview build

5 files changed · ± 5 modified

±Modified

• contents.html
• download.html
• library/pickletools.html
• whatsnew/3.15.html
• whatsnew/changelog.html

[hugovk]

Thanks for the review!