Add min, max, is_zero

[0xgleb]

Motivation

We need to use Solidity Float code in Rust

Solution

Expose min, max, and is_zero

Checks

By submitting this for review, I'm confirming I've done the following:

• made this PR as small as possible
• unit-tested any new functionality
• linked any relevant issues or PRs
• included screenshots (if this involves a front-end change)

Summary by CodeRabbit

• New Features

  • Added methods to compare two floats and return their minimum or maximum value.
  • Added a method to check if a float value is zero.

• Tests

  • Introduced comprehensive tests for the new comparison and zero-checking methods, including both manual and property-based tests.

[coderabbitai]

Walkthrough

Three new methods—min, max, and is_zero—were added to the Float struct. These methods interact with the DecimalFloat contract by constructing ABI-encoded calls, executing them in the EVM, and decoding the results. Comprehensive unit and property-based tests were introduced for these methods.

Changes

File(s)	Change Summary
crates/float/src/lib.rs	Added min, max, and is_zero methods to Float; implemented ABI/EVM contract calls and result decoding.
crates/float/src/lib.rs	Added unit and property-based tests for the new methods, covering correctness and edge cases.

Sequence Diagram(s)

sequenceDiagram
    participant Caller
    participant Float
    participant EVM
    participant DecimalFloatContract

    Caller->>Float: min(b)
    Float->>EVM: ABI-encoded minCall(a, b)
    EVM->>DecimalFloatContract: Execute minCall
    DecimalFloatContract-->>EVM: Return min result
    EVM-->>Float: Return encoded result
    Float-->>Caller: Decode and return Float

    Caller->>Float: is_zero()
    Float->>EVM: ABI-encoded isZeroCall(a)
    EVM->>DecimalFloatContract: Execute isZeroCall
    DecimalFloatContract-->>EVM: Return boolean result
    EVM-->>Float: Return encoded result
    Float-->>Caller: Decode and return bool

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Possibly related PRs

• 2025 04 04 min #25: Adds min and max functions and tests to the Solidity LibDecimalFloat library, directly relating to the Rust-side implementation of the same functionality in this PR.

Suggested labels

enhancement

Suggested reviewers

• findolor
• hardyjosh

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📥 Commits

Reviewing files that changed from the base of the PR and between c86ad7e and 6c02397.

📒 Files selected for processing (1)

• crates/float/src/lib.rs (2 hunks)

🧰 Additional context used

🧠 Learnings (1)

crates/float/src/lib.rs (1)

Learnt from: 0xgleb
PR: rainlanguage/rain.math.float#57
File: crates/float/src/lib.rs:316-328
Timestamp: 2025-06-18T09:10:41.740Z
Learning: In the rain.math.float codebase, the user prefers implementing standard Rust traits (like Neg) rather than creating redundant public methods when the trait already provides the needed functionality. Float implements Copy, so reference usage with operators is not a concern.

⏰ Context from checks skipped due to timeout of 90000ms (7)

• GitHub Check: rainix (ubuntu-latest, rainix-sol-static)
• GitHub Check: rainix (ubuntu-latest, test-wasm-build)
• GitHub Check: rainix (macos-latest, rainix-rs-test)
• GitHub Check: rainix (ubuntu-latest, rainix-rs-static)
• GitHub Check: rainix (ubuntu-latest, rainix-rs-test)
• GitHub Check: rainix (ubuntu-latest, rainix-sol-test)
• GitHub Check: git-clean

🔇 Additional comments (6)

crates/float/src/lib.rs (6)

337-346: LGTM! Clean implementation following established patterns.

The min method correctly follows the same pattern as other binary operations in the codebase, with proper ABI encoding, error handling, and result decoding.

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348-357: LGTM! Consistent with the min method implementation.

The max method correctly mirrors the min method structure and follows established patterns for binary operations.

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359-367: LGTM! Appropriate implementation for a predicate method.

The is_zero method correctly implements a unary predicate operation, returning bool instead of Float which is appropriate for a zero-check function.

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856-876: LGTM! Comprehensive manual testing with good edge case coverage.

The test covers important scenarios including different sign combinations, magnitude differences, and the edge case where both operands are identical.

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878-891: LGTM! Good coverage of zero representations.

The test properly covers various zero representations (-0, 0.0) which is important for floating-point zero detection, plus the negative case.

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893-952: LGTM! Excellent property-based testing with comprehensive mathematical properties.

The test covers all fundamental mathematical properties of min/max operations with detailed error messages for debugging. The property assertions are mathematically sound and provide thorough validation.

✨ Finishing Touches

• 📝 Generate Docstrings

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