Module string 

String Arithmetic Module - String Operations with Numeric Interactions

String-specific arithmetic operations including string multiplication, concatenation, and manipulation. This unifies strings into a typical numeric-compatible workloads. E.g., “hello” + “there” = “hellothere”. These are opt-in via the “str_arithmetic” feature.

Overview

• String multiplication: Repeat strings by numeric factors with configurable limits
• String-numeric conversions: Format numbers into string representations
• Categorical operations: Efficient string deduplication and categorical array generation
• Null-aware processing: Full Arrow-compatible null propagation

Features

• Memory efficiency: Uses string interning and categorical encoding to reduce allocation overhead
• Safety limits: Configurable multiplication limits prevent excessive memory usage
• Optional dependencies: String-numeric arithmetic gated behind str_arithmetic feature

Constants

W8

Auto-generated SIMD lane widths from build.rs SIMD lane count for 8-bit elements (u8, i8). Determined at build time based on target architecture capabilities, or overridden via SIMD_LANES_OVERRIDE.

W16

SIMD lane count for 16-bit elements (u16, i16). Determined at build time based on target architecture capabilities, or overridden via SIMD_LANES_OVERRIDE.

W32

SIMD lane count for 32-bit elements (u32, i32, f32). Determined at build time based on target architecture capabilities, or overridden via SIMD_LANES_OVERRIDE.

W64

SIMD lane count for 64-bit elements (u64, i64, f64). Determined at build time based on target architecture capabilities, or overridden via SIMD_LANES_OVERRIDE.

Functions

apply_dict32_dict32

Applies an element-wise binary operation between two CategoricalArray<u32> arrays, producing a new CategoricalArray<u32>. The result reuses or extends the unified dictionary from both input arrays and ensures deterministic interned value codes.

apply_dict32_num

Applies element-wise binary arithmetic op between CategoricalArray<u32>s a numeric slice.

apply_dict32_str

Applies element-wise binary arithmetic ops between a CategoricalArray<u32> and a StringArray<T>.

apply_str_dict32

Applies element-wise binary arithmetic ops between StringArray<T> and CategoricalArray<u32>

apply_str_float

Applies an element-wise binary operation between a StringArray<T> and a slice of floating-point values, producing a new StringArray<T>. Each operation is performed by interpreting the float as a finite decimal string representation (f64 formatted with ryu), and applying string transformations accordingly.

apply_str_num

String-numeric arithmetic operation dispatcher. Supports string multiplication (repeat string N times) with safety limits. Other operations pass through unchanged. Handles null propagation correctly.

apply_str_str

Applies an element-wise binary operation between two StringArrays, producing a new StringArray. Requires both arrays to have the same length.