neorusticus 0.1.3

A Prolog implementation in Rust with enhanced error handling
Documentation 
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// Copyright 2025 Jonas Forsman
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// Project name: neorusticus
// Filename: debug_list_test.rs
// Creator: Jonas Forsman

// Let's test what actually happens with list operations

use neorusticus::PrologEngine;

fn main() {
    let mut engine = PrologEngine::new();
    
    println!("Testing various list operations to see what actually happens...\n");
    
    // Test 1: member(X, L) - two uninstantiated variables
    println!("Test 1: member(X, L).");
    match engine.parse_query("member(X, L).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 2: member(X, atom_not_list) - atom as second argument
    println!("\nTest 2: member(X, atom_not_list).");
    match engine.parse_query("member(X, atom_not_list).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 3: member(X, 123) - number as second argument
    println!("\nTest 3: member(X, 123).");
    match engine.parse_query("member(X, 123).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 4: length(L, 3) - uninstantiated list
    println!("\nTest 4: length(L, 3).");
    match engine.parse_query("length(L, 3).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 5: length(atom, X) - atom as first argument
    println!("\nTest 5: length(atom, X).");
    match engine.parse_query("length(atom, X).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 6: append(atom, [1, 2], X) - atom as first argument
    println!("\nTest 6: append(atom, [1, 2], X).");
    match engine.parse_query("append(atom, [1, 2], X).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    // Test 7: append(X, Y, atom) - atom as third argument
    println!("\nTest 7: append(X, Y, atom).");
    match engine.parse_query("append(X, Y, atom).") {
        Ok(solutions) => println!("  SUCCESS: Found {} solutions", solutions.len()),
        Err(e) => println!("  ERROR: {}", e),
    }
    
    println!("\nBased on these results, we can see which operations actually error vs succeed with 0 solutions.");
}