cheapskate-terminal

Render markdown on the terminal. Ports msee from Node.js using the cheapskate markdown parser. Exposes a library and a command-line tool for doing so.

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Installing

$ stack install cheapskate-terminal

Library Usage

The library exports:

prettyPrint :: Doc -> IO ()

Example usage:

import           Cheapskate
import           Cheapskate.Terminal
import qualified Data.Text.IO        as Text (readFile)

main = do
    tc <- Text.readFile "test-file"
    prettyPrint (markdown def tc)

Haskell Source code highlighting

Pygments highlighting

Performance considerations

It's a complete implementation, but it's very reasonably inefficient; since when printing to the terminal (even with multiple megabytes of data), most of the time is spent printing - not parsing/manipulating - it's roughly as efficient as the Node.js implementation; however, I did a bad job with this... Without terminal wrapping it was about 10-20% faster, with terminal wrapping it's doing stupid conversions and a lot of copying.

It'll be battle-tested soon, but it's enough to say that it serves it's purpouse. For the actual usecase of pretty-printing markdown to the terminal (not 20MB files for benchmarking), it's actually much faster than JavaScript because it doesn't need to boot an interpreter or load a bunch of code.

If you can write a wrapping function that operates over a Text.Builder you'll make it a whole lot faster (challenge accepted?). This actually took me quite a bit to get working, ANSI escape sequences get in the way of wrapping text, since they mess-up with your notion of length, unless you have a fancy abstraction or an escape sequence parser.

I tried implementing this with ansi-terminal-builder, but eventually settled for dropping windows support. There's a branch with the stash at that point.

License

This code is published under the MIT License.

yamadapc / cheapskate-terminal Goto Github PK