Improve `Display` for `Value` in several ways by apoelstra · Pull Request #328 · BlockstreamResearch/rust-simplicity

apoelstra · 2025-12-11T14:43:00Z

Now we:

display bits and pairs of bits as bitstrings prefixed with 0b
display any bitstrings of length 4, 8, 16, ..., 2^32 as a hex string prefixed with 0x
display any remaining sum types as L(...) or R(...) rather than 0... or 1...

As an example of the improvement, consider this sample output from StderrTracker. Previously we had


[  58] exec jet(sha_256_ctx_8_finalize) (2^256? × (2^128? × (2^64? × (2^32? × (2^16? × 2^8?))))) × (2^64 × 2^256) → 2^256
       input ((1((((((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))),(((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))))),((((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))),(((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))))),(((((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))),(((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))))),((((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))),(((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))))))),(0,(0,(0,(0,0))))),(((((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0))))),(((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))),((((0,0),(0,0)),((0,0),(0,0))),(((0,0),(0,0)),((0,0),(0,0)))))),((((((((0,1),(1,0)),((1,0),(1,0))),(((0,0),(0,0)),((1,0),(0,1)))),((((1,1),(1,0)),((0,1),(1,0))),(((0,1),(1,0)),((0,1),(1,1))))),(((((1,0),(1,1)),((1,0),(1,1))),(((0,1),(1,0)),((0,1),(1,1)))),((((1,0),(1,0)),((1,1),(1,0))),(((1,0),(0,0)),((0,1),(0,1)))))),((((((0,0),(1,1)),((1,1),(0,0))),(((0,1),(1,0)),((1,1),(1,0)))),((((1,1),(1,1)),((0,0),(1,1))),(((0,1),(1,1)),((0,0),(1,0))))),(((((1,0),(1,0)),((0,1),(0,1))),(((0,1),(0,0)),((1,1),(1,1)))),((((1,1),(1,1)),((0,1),(0,1))),(((0,0),(1,1)),((1,0),(1,0))))))),(((((((0,1),(0,1)),((0,0),(0,1))),(((0,0),(0,0)),((1,1),(1,0)))),((((0,1),(0,1)),((0,0),(1,0))),(((0,1),(1,1)),((1,1),(1,1))))),(((((1,0),(0,1)),((1,0),(1,1))),(((0,0),(0,0)),((0,1),(0,1)))),((((0,1),(1,0)),((1,0),(0,0))),(((1,0),(0,0)),((1,1),(0,0)))))),((((((0,0),(0,1)),((1,1),(1,1))),(((1,0),(0,0)),((0,0),(1,1)))),((((1,1),(0,1)),((1,0),(0,1))),(((1,0),(1,0)),((1,0),(1,1))))),(((((0,1),(0,1)),((1,0),(1,1))),(((1,1),(1,0)),((0,0),(0,0)))),((((1,1),(0,0)),((1,1),(0,1))),(((0,0),(0,1)),((1,0),(0,1))))))))))
      output ((((((((0,1),(1,0)),((0,1),(1,0))),(((0,1),(1,0)),((1,0),(0,0)))),((((0,1),(1,1)),((1,0),(1,0))),(((1,0),(1,0)),((1,1),(0,1))))),(((((1,1),(1,1)),((1,0),(0,0))),(((0,1),(1,0)),((0,0),(1,0)))),((((1,0),(1,1)),((1,1),(0,1))),(((0,1),(1,1)),((0,1),(1,1)))))),((((((0,1),(1,0)),((1,1),(0,0))),(((1,0),(0,0)),((1,1),(1,1)))),((((1,1),(0,0)),((0,0),(0,1))),(((1,0),(0,0)),((1,0),(1,1))))),(((((1,0),(0,0)),((1,1),(1,0))),(((1,0),(0,1)),((1,1),(1,1)))),((((1,0),(0,0)),((1,1),(1,0))),(((0,0),(1,0)),((0,0),(0,0))))))),(((((((0,0),(0,0)),((1,0),(0,0))),(((1,0),(0,1)),((0,1),(1,1)))),((((0,0),(0,1)),((0,1),(0,0))),(((1,0),(0,0)),((0,1),(0,1))))),(((((0,1),(1,0)),((1,1),(1,0))),(((1,1),(1,0)),((0,0),(1,0)))),((((0,0),(1,1)),((0,0),(1,1))),(((1,0),(1,1)),((0,0),(1,1)))))),((((((1,0),(0,1)),((0,0),(0,0))),(((0,0),(1,0)),((1,0),(1,0)))),((((0,1),(0,1)),((1,0),(0,1))),(((0,0),(0,1)),((1,1),(0,1))))),(((((0,0),(0,0)),((1,1),(0,1))),(((0,1),(0,1)),((1,1),(1,1)))),((((0,0),(1,0)),((1,0),(0,1))),(((0,0),(1,0)),((0,1),(0,1))))))))

Now we have

[  58] exec jet(sha_256_ctx_8_finalize) (2^256? × (2^128? × (2^64? × (2^32? × (2^16? × 2^8?))))) × (2^64 × 2^256) → 2^256
       input ((R(0x0202020202020202020202020202020202020202020202020202020202020202),(L(ε),(L(ε),(L(ε),(L(ε),L(ε)))))),(0x0000000000000000,0x6a09e667bb67ae853c6ef372a54ff53a510e527f9b05688c1f83d9ab5be0cd19))
       output 0x75877bb41d393b5fb8455ce60ecd8dda001d06316496b14dfa7f895656eeca4a

I would like to get this in before #327.

ValueRef is a &-reference with a bit of small metadata attached. It should be Copy just like &Value is.

These all conceptually work on references to values, so they should be available from a ValueRef.

KyrylR · 2025-12-11T15:47:15Z

@@ -746,33 +768,63 @@ impl fmt::Display for Value {
        // a unit is displayed simply as 0 or 1.


This comment seems stale after the DispUnlessUnit removal

KyrylR · 2025-12-11T16:28:36Z

ACK 3890c47

Previously we would display left branches as 0 and right branches as 1, and had a special case where if the child node was unit, we would not display the inner (ε) to reduce noise. Now that we special-case all bitstrings, in particular bitstrings of length 1, this special-case is unnecessary and actually confusing. Now if we encounter a sum type we know it's *not* a bit and it would be clearer to indicate it as L or R, and if the child is a unit, we should unconditionally display that.

This was annoying me.

apoelstra · 2025-12-11T17:18:13Z

@KyrylR sorry, I messed up and one of my commits didn't pass tests because I updated a unit test in the wrong commit. Fixed.

KyrylR · 2025-12-11T17:23:18Z

ACK 5e5fbe2

apoelstra

On 5e5fbe2 successfully ran local tests

apoelstra added 4 commits December 11, 2025 14:40

value: use ValueRef internally in RawByteIter

22d5618

value: impl Copy for ValueRef

38c5776

ValueRef is a &-reference with a bit of small metadata attached. It should be Copy just like &Value is.

value: move iterator methods from Value to ValueRef

1ca2498

These all conceptually work on references to values, so they should be available from a ValueRef.

value: write out power-of-two length bitstrings compactly in Display

d2da3a0

apoelstra mentioned this pull request Dec 11, 2025

Bump simplicity-lang version #327

Closed

KyrylR reviewed Dec 11, 2025

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KyrylR approved these changes Dec 11, 2025

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apoelstra force-pushed the 2025-12/value-display branch from 2b71572 to 3890c47 Compare December 11, 2025 16:21

apoelstra added 3 commits December 11, 2025 17:17

value: write out bitstrings with len > 4 as hex rather than binary

6c88a8c

bit_machine: add missing space to StderrTracker

5e5fbe2

This was annoying me.

apoelstra force-pushed the 2025-12/value-display branch from 3890c47 to 5e5fbe2 Compare December 11, 2025 17:17

apoelstra commented Dec 11, 2025

View reviewed changes

apoelstra merged commit feb5671 into BlockstreamResearch:master Dec 11, 2025
24 checks passed

apoelstra deleted the 2025-12/value-display branch December 11, 2025 18:40

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Improve `Display` for `Value` in several ways#328

Improve `Display` for `Value` in several ways#328
apoelstra merged 7 commits intoBlockstreamResearch:masterfrom
apoelstra:2025-12/value-display

apoelstra commented Dec 11, 2025

Uh oh!

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		@@ -746,33 +768,63 @@ impl fmt::Display for Value {
		// a unit is displayed simply as 0 or 1.

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