slTrain/CHANGELOG.md

Changelog

All notable changes to the sl (Steam Locomotive) project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

[4.0.0] - 2026-08-09 — The Sea Update

Added

• Four vessels join the roster via -t: galleon (three-masted pirate ship with a flapping Jolly Roger, animated pennants, rigging, gunports, and a rubber-duck figurehead), steamer (sternwheeler whose paddle wheel turns on the same 4-frame machinery as the locomotive wheels, with churn that streams aft), sloop (racing yacht for narrow terminals), and tug (drawn in three-quarter perspective — it travels diagonally on the angle its art implies, so it appears to grow as it approaches the viewer)
• Animated sea for side-view vessels: a drifting swell pattern on the surface, deterministic glints below, hull bob on a slow sine, bow spray, and stern wake (three new particle kinds: spray, wake, bubble)
• -d/--dolphin — on special request, a dolphin dives ahead of the ship along its drawn angle, cut cleanly at the waterline, with splash. Requesting a dolphin with a train books sea passage instead
• At sea, -a finds an iceberg: crunch, shudder, bubbles, and a dignified descent below the waterline. The iceberg wins
• At sea, -F is the Flying Dutchman: the ship climbs out of the water trailing stardust while the sea stays below
• Per-vessel whistles for -w: the steamer HOOOONKs, the tug TOOOOTs, the galleon goes YARRR!, the sloop rings its little bell
• Per-vessel liveries (white sails, red hulls, brass fittings), honored in surprise mode too
• Surprise mode: about 1 typo in 3 is now nautical; dolphins accompany 1 in 5 sea voyages
• CODE_OF_CONDUCT.md (Contributor Covenant 2.1), fixing the broken link in CONTRIBUTING.md
• --speed help text now documents the 0.1–20 clamp

Changed

• -n/--cars is rail-only; coal cars do not float and the count is ignored at sea (documented in --help)
• -t/--type now fully overrides -l: it no longer inherits the two implicit coal cars (-l alone still couples them)

Fixed

• Trailing smoke now lingers and dissipates after the train exits, instead of being cut off the moment the last car leaves the screen
• In accident mode on terminals narrower than the train, the crash now happens at the left edge instead of off-screen
• make demo labeled its first run "Classic Train" but ran surprise mode; it now runs ./sl -t classic
• LICENSE copyright year updated to 2024-2026

Notes

• Tug and dolphin artwork adapted from reference pieces contributed by the project author

[3.1.0] - 2026-07-06

Added

• Surprise mode: a bare sl (the classic mistyped ls) now randomizes the whole show each run — train type, coal-car count, color livery (named themes plus fully random one-offs), and speed, with an occasional whistle (25%), a rare flight (10%), and a very rare crash (5%)

Changed

• Any command-line flag disables surprise mode entirely; explicit options remain fully deterministic and backward compatible

[3.0.0] - 2026-07-06

Added

• Flicker-free double-buffered renderer on the alternate screen — the frame is composed off-screen and emitted as a single write, and your previous terminal contents are restored when the train has passed
• Animated wheels with a 4-frame rotation cycle on every train type
• Particle-based smoke that drifts behind the train and dissipates, with grayscale shading on 256-color terminals
• Coal cars (-n/--cars, up to 8), adapted from Toyoda Masashi's original sl
• Train type selection flag (-t/--type: classic, small, d51, c51)
• Whistle (-w/--whistle) — the train toots as it passes
• Rebuilt accident mode: screen shake, spark shower, and smoldering wreck
• Rebuilt flying mode: smoothstep climb with stardust trail
• Static train output when stdout is not a terminal, so sl | cat prints a train instead of escape codes
• Color control: --no-color flag, NO_COLOR environment variable honored
• Monotonic frame pacing (animation speed no longer drifts with render time)
• Speed clamping (0.1–20.0) so -s 0 can no longer hang the animation
• Professional project documentation (CONTRIBUTING.md, etc.)
• Enhanced README with badges and comprehensive information
• Links to StevenMilanese.com throughout documentation

Changed

• -l/--long now couples two coal cars behind the D51, making the long train actually long
• Terminal resize is applied at the next frame instead of mid-draw
• SIGWINCH handler is only registered on platforms that have it (Windows compatibility)

Fixed

• Full-screen clear per frame caused visible flicker; replaced by the double-buffered renderer
• Character-by-character color replacement could corrupt output when the train was clipped at the screen edge
• Escape codes were written even when stdout was a pipe or file
• Flying mode drifted downward instead of flying
• Degenerate terminal sizes (0×0 pseudo-terminals) now fall back to 80×24

[2.0.0] - 2024-06-05

Added

• Complete rewrite as a standalone Python script
• Multiple train types (Classic, D51, C51)
• Flying mode (-F flag)
• Accident mode (-a flag)
• Speed control (-s option)
• Colorful ASCII art with ANSI escape sequences
• Dynamic smoke generation
• Terminal resize handling (SIGWINCH)
• Graceful interrupt handling (SIGINT)
• Comprehensive help system
• No external dependencies (pure Python)

Changed

• Migrated from simple script to professional command-line tool
• Improved animation smoothness
• Better terminal compatibility

Removed

• Dependency on colorama (now uses built-in ANSI codes)

[1.0.0] - 2024-06-01

Added

• Initial release
• Basic train animation
• Simple colorful output using colorama
• Right-to-left animation

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For more information, visit StevenMilanese.com