What's changed

Language

• +Tree-walking interpreter rewritten from Go to Rust
• +First-class functions, closures, and recursion
• +Structs with default field values and dot-notation access
• +Module and import system for stdlib and .cl files
• +Control flow: if / elseif / else, while, for, break, continue
• +Operators: arithmetic (** //), comparison, logical (&& ||), compound assignment, prefix/postfix ++/--
• +Types: Integer, Float, String, Char, Boolean, Array, Hash, Null, Function, Struct, Module

Standard library

• +fmt — print, eprint, input, typeof, to_int, to_float, to_str, clear
• +math — PI, E, sqrt, abs, pow, floor, ceil, round, log, sin, cos, tan, min, max, clamp
• +strings — to_upper, to_lower, split, join, contains, replace, trim, reverse, to_chars, from_chars, parse_int, parse_float
• +arrays — 20 functions including push, pop, slice, sort, zip, flatten, unique
• +hash — keys, values, entries, has_key, merge, delete, len
• +fs — read_file, write_file, append_file, read_lines, exists, list_dir, mkdir, copy, rename, remove
• +path — join, basename, dirname, stem, extension, absolute, is_absolute
• +os — args, platform, arch, get_env, set_env, get_wd, hostname, exit
• +time — now, unix, sleep, since, format, year/month/day/hour/minute/second
• +json — parse, stringify
• +rand — int, float, choice, shuffle
• +http — get, post, post_json (blocking, returns status/body/ok)

Errors

• +All errors carry line and column from the call site
• +Error output shows source line with caret pointer
• +Parse errors surface to the user before evaluation begins
• +Non-zero exit code on any error in script mode

REPL

• +Persistent history across sessions (~/.code_lang_history)
• +exit, exit(), and quit all exit cleanly
• +Errors print to stderr without crashing the session