Ragnar is a programming language made for fun, and carefully vibecoded using Antigravity.

• inspired by Rebol. Many core features from Rebol are implemented, including the object system and the powerfull parse function.
• hosted in .NET with decent interop.
• made to be useful from the command line, and have a REPL.
• has a simple actor model implementation inspired by Erlang.
• is functional
  • lexically scoped, and all functions are closures (unlike Rebol).
  • has tail-call optimized recursion (TCO).
  • has functional composition inspired by F#.
  • has partial application inspired by Clojure.

Ragnar homepage: tormaroe.github.io/ragnar

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Ragnar Quick Reference & Cheat Sheet

Scoping

• Hybrid Binding: Functions evaluate in a local context with a lexical parent (DefiningContext) and dynamic parent (caller context).
• Lookup: Word resolution traverses the lexical parent chain first, falling back to the dynamic parent chain.
• Assignment: Setting a word updates its nearest bound parent context. Inside a function frame, updates do not traverse past the global context, defaulting to local assignment unless forced global.

Functions, Closures & TCO

• Closures: Functions defined via func or does capture their lexical definition environment.
• Tail Call Optimization (TCO): The interpreter optimizes tail calls by returning a TailCall token, resolved iteratively in a trampoline loop.

REPL Features

• Special Variable it: Evaluates to the last printed/computed result in the context chain.
• Auto-completion:
  • Tab / Right Arrow: Cycle forward through context bindings matching the prefix.
  • Shift + Tab / Left Arrow: Cycle backward.
  • Escape: Cancel and restore original input.
  • Enter: Accept selection and execute.
• Navigation & Editing: Up/Down (history navigation), Left/Right (cursor movement), Home/End (cursor jump), Backspace/Delete.
• Persistent History: Executed commands are saved asynchronously to a .ragnar_history file in the user's home directory and loaded on REPL startup (capped at 1,000 entries; filters consecutive duplicates).
• Customization: Configure custom behavior at runtime via:
  • system/console/prompt: Set a string or evaluation block for prompt.
  • system/console/result: Set prefix for evaluated output (defaults to == ).
  • system/console/history: Block storing command line history.
• Startup Script: Evaluates .ragnar.r in the user's home directory.

Executing Scripts & Command Line Arguments

• Unix Shebang Support: Scripts can start with a hashbang line (e.g., #!/usr/bin/env ragnar) and be marked as executable (chmod +x script.r) to run them directly.
• Positional Command Line Invocation: Execute a script by passing its path directly as the first argument, e.g. ragnar script.r arg1 arg2. Ragnar options parsing stops at the script path (or at the -- separator), allowing script-specific arguments and flags.
• Accessing Arguments: Scripts can access the block of arguments passed to them as string (Text) values via the system/options/args path.

Core Vocabulary & Functions

All native and mezzanine functions categorized:

• Constants: true, false, none
• Output & Evaluation: print, prin, do, probe
• Conditionals: if, either, all, any, case, switch
• Loops & Iteration: loop, forever, while, foreach, enumerate, map-each, map, flatmap, filter, fold, break, continue
• Math & Comparison: add, +, sub, -, multiply, mul, *, divide, /, remainder, //, random, abs, max, min, negate, zero?, greater?, >, less?, <, equal?, =, ==, not-equal?, <>, !=, greater-or-equal?, >=, less-or-equal?, <=
• Logical: not, and, and?, or, or?, xor, xor?
• Objects & Contexts: make, in, get, set, bind, use, let, context?, object!, error!, system
• Series & Blocks: first, second, next, last, length?, empty?, find, append, join, pick, select, poke, index?, copy, sort, reverse, back, head, tail, head?, tail?, clear, remove, take, reduce, compose, block?, paren?, record?
• Strings & Characters: trim, replace, uppercase, lowercase, split, char?, charset, text?, string?, reform, rejoin
• Control Flow: func, does, return, exit, quit, try, attempt, catch, throw, ignore, _
• Functional Operators: >>, <<, partial, |, |>, >|, |>>, >|>, >>|
• IO & File System: read, write, load, save, cd, ls, mkdir, rmdir, rm, pushd, popd, mv, cp, pwd, what-dir, ask, confirm, exists?
• .NET Interop: get-type, new, call-method, get-prop, set-prop, get-static, call-static
• Inspection & OS: what, help, ?, type?, format, call, home, get-env, set-env, list-env, now, wait, rc-file-name
• Actors (Erlang-like): spawn, tell, kill, receive
• Compression: zip, unzip, native-zip, native-unzip
• Parsing: parse