chapter08.md

Chapter 8: Strings, Text, and Math

NAAb's native Standard Library provides robust modules for handling common data types like strings and numbers. This chapter explores the string module for text manipulation, the regex module for powerful pattern matching, and the math module for various mathematical operations. All these modules are implemented in high-performance C++, making them significantly faster than equivalent polyglot solutions.

8.1 The string Module: Manipulation and Parsing

The string module (commonly aliased as str) offers a comprehensive set of functions for working with text. From basic case conversions to splitting and joining, these functions streamline common string operations.

use string as str // Import the string module

main {
    let message = "  Hello, NAAb World!  "
    print("Original message:", message)

    // Basic manipulation
    let trimmed = str.trim(message)
    print("Trimmed:", trimmed) // Output: "Hello, NAAb World!"

    let upper = str.upper(trimmed)
    print("Uppercase:", upper) // Output: "HELLO, NAAB WORLD!"

    let lower = str.lower(upper)
    print("Lowercase:", lower) // Output: "hello, naab world!"

    // Length
    print("Length:", str.length(message)) // Output: 22

    // Splitting and Joining
    let csv_data = "apple,banana,cherry"
    let fruits = str.split(csv_data, ",")
    print("Split fruits:", fruits) // Output: ["apple", "banana", "cherry"]

    let joined_data = str.join(fruits, " | ")
    print("Joined data:", joined_data) // Output: "apple | banana | cherry"

    // Substring and Indexing
    let full_string = "NAAb Programming"
    let sub = str.substring(full_string, 5, 8) // Get "Pro"
    print("Substring 'Pro':", sub) // Output: Pro

    let index = str.index_of(full_string, "Program")
    print("Index of 'Program':", index) // Output: 5 (0-indexed)

    // Repetition
    let repeated = str.repeat("NAAb", 3)
    print("Repeated 'NAAb':", repeated) // Output: NAAbNAAbNAAb
}

8.2 The regex Module: Pattern Matching

The regex module provides powerful tools for defining and applying regular expressions to text. This enables sophisticated pattern matching, searching, and replacement capabilities.

use regex as re // Import the regex module

main {
    let text = "The quick brown fox jumps over the lazy dog."
    let pattern = "fox|dog"

    // Check if pattern matches anywhere in the string (use 'search' for partial, 'match' for full)
    let matches_any = re.search(text, pattern)
    print("Text matches 'fox|dog':", matches_any) // Output: true

    // Find all occurrences
    let all_found = re.find_all(text, "[a-z]+") // Find all words
    print("All words:", all_found) // Output: ["The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"]

    // Replace occurrences
    let replaced_text = re.replace(text, "fox", "cat")
    print("Replaced 'fox' with 'cat':", replaced_text) // Output: "The quick brown cat jumps over the lazy dog."

    // Check for a full match (from start to end of string)
    let full_match_test = re.matches("NAAb", "^NAAb$")
    print("'NAAb' fully matches '^NAAb$':", full_match_test) // Output: true

    let no_full_match = re.matches("NAAb Language", "^NAAb$")
    print("'NAAb Language' fully matches '^NAAb$':", no_full_match) // Output: false
}

Note: The re.find_all function takes an optional flag for case-insensitivity or other regex options.

8.3 The math Module: Advanced Calculation

The math module (aliased as math) provides a collection of mathematical functions and constants, including trigonometric functions, powers, roots, and absolute values.

use math as math // Import the math module

main {
    // Basic arithmetic functions
    print("Absolute value of -10:", math.abs(-10)) // Output: 10
    print("Square root of 25:", math.sqrt(25.0))   // Output: 5.0

    // Powers
    print("2 to the power of 8:", math.pow(2.0, 8.0)) // Output: 256.0

    // Rounding and truncation
    print("Floor of 3.7:", math.floor(3.7)) // Output: 3.0
    print("Ceil of 3.2:", math.ceil(3.2))   // Output: 4.0
    print("Round of 3.4:", math.round(3.4)) // Output: 3.0
    print("Round of 3.8:", math.round(3.8)) // Output: 4.0

    // Min and Max
    print("Min of (10, 20):", math.min(10, 20)) // Output: 10
    print("Max of (10, 20):", math.max(10, 20)) // Output: 20

    // Mathematical constants
    print("Value of PI:", math.PI) // Output: 3.14159...
    print("Value of E:", math.E)   // Output: 2.71828...
}

Note: Many mathematical functions operate on float types. Ensure you pass floating-point literals (e.g., 25.0 instead of 25) where appropriate to avoid implicit conversions or function mismatches.